bluuebunny/crossref_metadata_2025 huggingface dataset:
Maternal high fat diet results in altered body composition in first generation male offspring at weaning but not adulthood
Authors: Miotto Paula Michelle , Castelli Laura M , MacPherson Rebecca E , Johnston Bryan D , LeBlanc Paul J , Roy Brian D , Peters Sandra J , Ward Wendy E
Published: June 2021

Previous research has shown that feeding a high fat diet can result in adverse effects to body composition in male rodents. The potential adverse effects of maternal high fat feeding on body composition of male offspring is less clear. Our study objective was to determine if maternal high fat feeding leads to higher fat mass and lower lean and bone mass in male Wistar offspring at 19 days (weaning) and 3 months of age (young adulthood). Female Wistar rats were randomized to either a control (C, AIN93G, 7% soybean oil by weight, n = 11) or high fat (HF, modified AIN93G, 20% lard by weight, n = 12) diet at 28 days of age. After 10 weeks of feeding, females were bred and consumed their respective diets throughout pregnancy and lactation. Body composition of male offspring was measured using dual‐energy X‐ray absorptiometry (DEXA) at age 19 days or at 3 months of age. Greater body weight (p < 0.05) and absolute fat (p < 0.001) and bone mass (both bone mineral content (BMC) and density (BMD); p<0.05) was observed at 19 days in offspring from mothers fed HF compared to C diet. When expressed relative to body weight, fat mass was higher (p <0.001) at 19 days in offspring of mothers fed HF compared to C diet. Interestingly, differences in body weight, fat mass, BMC and BMD were not sustained at young adulthood (age 3 months). The effects at weaning are fully attenuated by 3 months of age when male offspring are fed a ‘healthy’ control diet from weaning onwards.
Predictors of Serum 25(OH)D in Elderly African‐Americans in the Health, Aging, and Body Composition (Health ABC) Study
Authors: Hansen J G , Hootman K , Tang W , Brannon P M , Kritchevsky S , Houston D , Harris T , Garcia M , Liu Y , Lohman K , Cassano P A
Published: June 2021

Inadequate vitamin D status is highly prevalent in elderly individuals, and has been associated with adverse health outcomes. This study's objective was to investigate predictors of serum 25(OH)D in approximately 1,000 African‐American Health ABC participants. General linear models were used to evaluate associations between predictor variables and log‐transformed serum 25(OH)D.

In a multivariate model, age, gender, study site, height, season of blood draw, physical activity, multivitamin use, vitamin D supplement use, dietary patterns, and body mass index (BMI) explained 22% of the variation in serum 25(OH)D. The main explanatory variable was multivitamin use, which accounted for 11% of serum 25(OH)D variability; multivitamin users had 7.2 ng/mL higher serum concentrations compared to non‐users. BMI was inversely associated, and explained about 1.8% of the variance in serum 25(OH)D. However, the BMI—25(OH)D association was non‐linear, and mainly reflected associations in obese participants (BMI≥30); models including a quadratic BMI term explained more variability than the linear BMI model (R2 2.5% vs. 1.8%).

In this elderly population, BMI was negatively associated with serum 25(OH)D and multivitamin use was the primary contributor to variability.

Grant Funding Source: NIA: N01‐AG‐6–2101, N01‐AG‐6–2103, N01‐AG‐6–2106, R01‐AG028050; RC1 AG035835; NINR: R01‐NR012459; NRSA T32‐DK‐7158–36 (JGH)
Formate metabolism is altered in riboflavin‐deficient rats
Authors: MacMillan Luke , Lamarre Simon , Andrivon Estelle , Dickie Charlotte , Brosnan Margaret E. , Brosnan John T.
Published: June 2021

Riboflavin can play an important role in one‐carbon metabolism, particularly as its active forms, FAD and FMN, are used as cofactors in both the production and utilization of formate.

Rats were fed either a riboflavin‐replete or a riboflavin‐deficient diet for 13 days at which point blood and tissue samples were taken. Riboflavin deficiency was assessed by the Erythrocyte Glutathione Reductase activation coefficient (EGRac). Total plasma homocysteine (Hcy), hepatic S‐adenosylmethionine (SAM), and S‐adenosylhomocysteine (SAH) concentrations were analyzed by HPLC. Hepatic methylenetetrahydrofolate reductase (MTHFR) was assessed by means of enzyme activity and immunoblot. Plasma formate was analyzed by GC‐MS.

EGRac confirmed riboflavin deficiency. Plasma Hcy was elevated in the deficient animals. Hepatic SAM was lower in the deficient animals; there was no difference in SAH. MTHFR was found to be markedly reduced in the deficient group; plasma formate concentration was decreased by about 20%.

The increased plasma Hcy and reduced hepatic SAM indicate an impairment in re‐methylation. The decreased plasma formate levels coupled with the defective remethylation suggest that the flavin‐dependent formate production may be decreased. This will be further examined by means of isotopic experiments to measure the endogenous rates of formate production.

Grant Funding Source: Canadian Institutes of Health Research & Research Development Corporation of Newfoundland and Labrador
In vivo Effect of 1‐Amino D‐Proline, an Anti‐pyridoxine Factor, on the Metabolism of Vitamin B6‐dependent Enzymes in Moderately Vitamin B6 Deficient Rats
Authors: Mayengbam Shyamchand , Raposo Sara , Aliani Michel , House James D.
Published: June 2021

Pyridoxal 5′‐phosphate (PLP) serves as an important cofactor in numerous metabolic pathways, including the transsulfuration pathway which converts homocysteine (Hcy) to cysteine (Cys). While overt deficiency is rare, marginal deficiency is common, and may be exacerbated by anti‐pyridoxine factors in the food supply. To this end, a study was conducted to examine the in vivo effect of 1‐amino D‐proline (1ADP), an anti‐pyridoxine factor found in flaxseed, on indices of sulphur amino acid metabolism in moderately B6‐deficient rats. Male weaning rats (n=6/treatment) received a semi‐purified diet (AIN‐93G) containing either 7 (control; C) or 0.7 mg/Kg diet PN·HCl (moderately deficient; MD), each with one of 4 levels of 1ADP, viz. 0, 0.1,1 and 10 mg/Kg, diet for 5 weeks. For rats receiving the C diet, final body weight was not affected by 1ADP, however rats consuming the highest 1ADP levels in the MD group were significantly lighter (p<0.001). Plasma biomarkers are given in Table 1. The data provide evidence that the consumption of an anti‐pyridoxine factor linked to flaxseed does not pose challenges for subjects who are vitamin B6‐replete. However, this may not be the case for subjects with marginal B6 status, as supported by dose‐dependent reductions in plasma PLP and increases in plasma Hcy.

Grant Funding Source: Natural Sciences and Engineering Research Council of Canada (NSERC).
Plasma homocysteine is directly correlated with white matter hyperintensity and lateral ventricular volume, and inversely correlated with regional brain volumes in folic acid fortified, cognitively intact older adults
Authors: Miller Joshua W , Green Ralph , Lin Xin , Bettcher Brianne M , Wilheim Reva , Racine Caroline A , Yaffe Kristine , Miller Bruce L , Kramer Joel H
Published: June 2021

Folic acid (FA) fortification has reduced the prevalence of hyperhomocysteinemia (HHcy) in the United States, but plasma homocysteine (Hcy) remains a modifiable risk factor for cognitive impairment and dementia. We investigated associations between white matter hyperintensity (WMH) and regional brain volumes, determined by structural MRI scans, and Hcy in cognitively intact, community dwelling older adults exposed to FA fortification (N=191, age 72±6y, Mini Mental State Score >;25). Mean Hcy was 8.6±3.7 μmol/L and 8.3% had HHcy (>;13 μmol/L). Mean RBC folate was 544±150 ng/ml and none was folate deficient (<160 ng/ml). Determinants of Hcy were age, education, vitamin B12, and creatinine. Folate was not correlated with Hcy. When controlling for age, gender, education, intracranial volume, folate, B12, and creatinine, Hcy was directly correlated with WMH (p=0.03) and lateral ventricular volume (p≤0.02), and inversely correlated with hippocampus (p≤0.08), amygdala (p≤0.01), basal ganglia (p≤0.06), and medial temporal lobe (p≤0.04) volumes. These results indicate that in folate replete, cognitively intact older adults, HCY is associated with WMH and structural deficits in and around the medial temporal lobe. It remains to be determined if Hcy predicts loss of volume in these brain regions and associated cognitive functions over time. NIH AG023501, AG032289; Hillblom Foundation; Private Foundation
Rosemary extract regulates glucose and lipid metabolism by activating AMPK and PPAR pathways in HepG2 cells
Authors: Tu Zheng (Alex) , Moss‐Pierce Tijuana , Ford Paul , Jiang Alan
Published: June 2021

An epidemic of metabolic disorders such as diabetes and obesity is rising dramatically, affecting ~30% of the US adult population. Using natural products as potential therapeutic and preventive interventions has drawn worldwide attention. Rosemary has been shown to lower blood glucose, cholesterol levels and mitigate weight gain in several in vivo studies; however, the mechanisms are essentially unknown. We investigated the effects of rosemary on metabolism in hepatocyte HepG2 and demonstrated that rosemary extracts (RE) significantly increase glucose consumption by 21%. The phosphorylation of AMP‐activated protein kinase (AMPK), as well as its substrate, acetyl‐CoA carboxylase (ACC) was increased by RE treatment. RE also transcriptionally regulate genes involved in metabolism, including SIRT1 (up 2.9‐fold), PPARγ coactivator 1α (PGC1α, up 1.7‐fold), low density lipoprotein receptor (up 2‐fold), glucose‐6‐phosphatase (down 65%), and ACC (down 32%). Furthermore, the PPARγ specific antagonist GW9662 diminished rosemary's effects on glucose consumption, indicating PPAR pathways contribute to rosemary's effects. Overall, our study suggested that RE potentially increase liver glycolysis and fatty acid oxidation, while decrease gluconeogenesis and fatty acid synthesis by activating the AMPK and PPAR pathways.
Early life exposure to soy isoflavones in combination with an adequate but not supplemental level of folic acid improves bone development of CD‐1 mice by suppressing expression of neuropeptide Y
Authors: Kaludjerovic Jovana , Ward Wendy E
Published: June 2021

Early life exposure to soy isoflavones (ISO) improves bone health of female mice at adulthood. This benefit may be mediated by methylation of CpG sites that regulate transcription of genes involved in bone formation. The objective was to examine if early life exposure to ISO and supplemental folic acid (FA), a methyl donor, induces permanent changes in bone‐specific gene expression that result in stronger bones at adulthood in female CD‐1 mice. Mice were randomized to adequate (2 mg/kg diet) or supplemental (8 mg/kg diet) FA during pregnancy and lactation. Offspring received corn oil or ISO (7 mg/kg body weight/day) from day 1 to 10 of life and adequate FA diet until age 4 months. Contrary to our hypothesis, exposure to ISO + supplemental FA had a modest effect on lumbar spine (higher bone mineral density (BMD)) with no effect on femurs. This may be due to higher expression of bone resorption genes, i.e. beta‐catenin and parathyroid hormone receptor 1. In contrast, females exposed to adequate FA + ISO had higher BMD, improved trabecular connectivity and greater strength at the femur and lumbar spine that may be explained by lower expression of neuropeptide Y – a neurotransmitter that is inversely associated with bone formation. Early life exposure to ISO has contrasting effects on adult bone health, depending on the level of FA in the diet. Benefits to BMD, bone structure as well as bone strength were only observed with adequate FA.

Grant Funding Source: Canadian Institutes of Health Research (funding number 89941) and a Frederick Banting and Charles Best Canada Graduate Scholarship
An epigenetic perspective on pharmacologic ascorbate in colon cancer
Authors: Kaiser Matthew Carl , Rajendran Praveen , Dashwood Mohaiza W , Levine Mark A , Michaels Alexander , Frei Balz , Dashwood Roderick H
Published: June 2021

Aim

There is growing interest in pharmacologic ascorbate (Asc) and its therapeutic properties (Levine et al. Adv Nutr 2011;2:78). We examined cell viability, histone deacetylase (HDAC) expression, and related protein modifications in cancer versus noncancer colon epithelial cells following exposure to Asc.

Methods

MTT assays were conducted in HCT116 colon cancer and CCD841 non‐transformed colonic epithelial cells treated with 0.25 to 16 mM Asc or ascorbate‐2‐phosphate (AAp), in the presence and absence of catalase (CAT, 280 U/mg), or with 5 to 160 μM H2O2. Cell lysates obtained 6 h and 24 h post‐treatment were immunoblotted as reported by Rajendran et al. Mol Cancer 2011;10:68.

Results

In MTT assays, IC50 data were as follows: 8 mM Asc (CCD841); 3 mM Asc (HCT116), >;50mM AAp (HCT116), and 65 μM H2O2 (HCT116). CAT protected against both Asc‐ and H2O2‐ induced cytotoxicity. At 6 h, Asc and H2O2 altered the expression of HDACs (HDAC4, HDAC6, SIRT3) and enhanced the acetylation of histone (H3, H4) and non‐histone proteins (tubulin, p53).

Conclusions

Asc was more cytotoxic to colon cancer cells than non‐cancer cells. Findings with the non‐H2O2 producing compound AAp, and with CAT, implicated H2O2 in Asc‐induced cytotoxicity. Asc was shown, for the first time, to alter epigenetic end‐points related to HDAC changes in colon cancer cells.

Grant Funding Source: CA090890, CA090890, AT002034
Pomegranate Polyphenols Suppress Colorectal Aberrant Crypt Foci (ACF) and Inflammation: Possible role of miR126 in vitro and in vivo
Authors: Banerjee Nivedita , Kim Hyemee , Talcott Stephen , Talcott Susanne U Mertens
Published: June 2021

The anti‐tumorigenic efficacy of polyphenols ellagitannins and anthocyanins extracted from pomegranate has been extensively studied in various cancer models. The objective of this study was to investigate the role of post‐transcriptional regulation of apoptotic and inflammatory biomarkers by specific microRNAs treated with pomegranate polyphenols (PP).

mRNA, microRNA expression were measured by RT‐PCR, protein by western blotting and multiplex bead assay. In vivo studies were performed with Sprague Dawley rats.

PP juice suppressed the number of high multiplicity aberrant crypts foci (HMACF >; 4 ACF) by 42% (P<0.05) and lowered Ki67 antigen. Cell proliferation was also inhibited by PP (5–25 μg/mL) in colon cancer cells HT‐29. In vitro and vivo results were accompanied by a downregulation of expression including NF‐κB, inducible nitric oxide synthase (iNOS), cyclooxygenase‐2 (COX‐2), vascular adhesion molecule‐1 (VCAM‐1), insulin growth factor (IGF) and PI3K/Akt/mTOR signaling pathways. miRNA 126 is frequently lost in colon cancer and targets VCAM‐1 and PI3K. PP increased miR126 expression. In vitro, the involvement of miR‐126 was confirmed using the antagomir for miR‐126, where PP reversed the effects of the antagomir.

In summary Pg inhibited HT29 cell proliferation, suppressed the number of HMACF formation and colon tumorgenesis where microRNA 126‐regulated pathways seem to be involved.

Grant Funding Source: Vegetable and Fruit Improvement Center, Texas AandM University
Pomegranate Polyphenolics reduce inflammation in Intestinal Colitis ‐ Potential Involvement of the miR‐145/p70S6K/HIF1α Pathway
Authors: Kim Hyemee , Banerjee Nivedita , Pfent Catherine , Talcott Stephen , Mertens‐Talcott Susanne
Published: June 2021

Pomegranate polyphenolics have previously been demonstrated effective in the prevention of inflammation and carcinogenesis. To determine the anti‐inflammatory effects and possible mechanisms of pomegranate polyphenolics in colitis, the mRNA and protein levels were assessed in colonic mucosa by RT‐PCR, western blotting and multiplex bead assay.

Compared to the control, pomegranate suppressed cell proliferation (37.5%), and protected against DSS‐induced colon inflammation and injury (50% and 66.7%). Pomegranate significantly down‐regulated phosphorylation of p70S6K, and decreased HIF1α expression. p70S6K is the direct target of miR‐145. Induction of miR‐145 by pomegranate juice (2.0 fold) compared to control juice corresponds to the down‐regulation of p70S6K. Pomegranate significantly attenuated the expresison of pro‐inflammatory cytokines (TNF‐α, Il‐1β and Il‐10), COX‐2 and iNOS. The involvement of miR‐145/p70S6K/HIF1α was additionally investigated in CCD18Co colon‐myofibroblastic cells, where the involvement of this pathway was confirmed using the specific antagomiR of miR‐145, where the effects of pomegranate polyphenolics were in part reversed by the antagomir.

These results suggest that pomegranate intake attenuated DSS‐induced colitis by modulating the miR‐145/p70S6K/HIF1α pathway and inhibiting inflammatory responses, and it may be a potential therapeutic for colitis.

Grant Funding Source: Vegetable & Fruit Improvement Center (TAMU)
The effect of eggs on satiety in children and adolescents
Authors: Liu Ann , Puyau Renee S , Han Hongmei , Johnson William D , Greenway Frank L , Dhurandhar Nikhil V
Published: June 2021

Consumption of an egg breakfast may aid in body weight regulation through promotion of satiety. Dietary interventions are particularly relevant for children since the use of drugs and bariatric surgery are not commonly recommended. In a randomized crossover trial, we evaluated the effects of an egg breakfast vs. an isocaloric bagel breakfast on subsequent food intake in children (age 4–6 years, n=13) and adolescents (age 14–17 years, n=15). There were no differences in lunch time food intake between the two breakfast treatments for either age group. Visual analog scale ratings of hunger and satiety were also not different between the two treatments in adolescents. Consumption of the egg breakfast led to a significant increase in serum PYY levels (P = 0.0001) in adolescents. However, increased levels of PYY were not correlated with decreased food intake. These data demonstrate that egg consumption does not alter short‐term food intake in children, and they suggest that adolescents may not be as responsive to changes in appetite hormones as adults. This work is registered at ClinicalTrials.gov NCT01530061.

Grant Funding Source: American Egg Board
Daily Addition of a Protein‐rich Breakfast for Long‐term Improvements In Energy Intake Regulation and Body Weight Management in Overweight & Obese ‘Breakfast Skipping’ Young People
Authors: Leidy Heather J , Hoertel Heather A , Douglas Steve M , Shafer Rebecca S
Published: June 2021

Purpose

To identify whether the daily addition of a Normal‐ Protein (NP) vs. High‐Protein (HP) breakfast leads to long‐term improvements in energy intake regulation and body weight management in overweight/obese breakfast skipping (BS) young people.

Methods

Fifty‐seven BS older adolescents (age: 19±1y; BMI: 29.7±4.6kg/m2) were randomly assigned to 12wks of consuming a NP cereal‐based breakfast (350 kcal; 15% Protein/65% CHO/20% Fat), HP pork‐based breakfast (350 kcal; 40% Protein/40% CHO/20% Fat), or no breakfast (BS). Daily hunger and satiety, energy intake, and body weight/composition were measured pre and post‐study.

Results

HP breakfast led to reduced daily hunger and increased daily fullness over the 12wks vs. CON and NP (both, p<0.05). HP breakfast also led to voluntary reductions in daily intake (−412±228kcal/d, p=0.08) over the 12wks, whereas CON and NP did not. The reduction in intake within the HP group was due to a reduction in unhealthy evening snacking of high fat/high sugar foods. Although no change in body weight was observed between groups, CON led to an increase in body fat mass (+1.58±0.87kg; p<0.05) vs. NP and HP (both, p<0.05).

Conclusions

The daily addition of breakfast, particularly rich in dietary protein, improved energy intake regulation and body weight management in overweight/obese ‘breakfast skipping’ adolescents.

Grant Funding Source: The National Pork Board
Lysophosphatidylcholine‐induced mitochondrial ROS formation and activation of AMPK promote macrophage chemotaxis and efferocytosis
Authors: Jiang Shaoning , Park Dae Won , Bae Hong‐Beom , Zmijewski Jaroslaw W
Published: June 2021

Clearance of apoptotic cells is a critical step for efficient resolution of inflammatory conditions, including those resulted from acute lung injury (ALI). Lysophosphatidylcholine (LysoPC) is a bioactive phospholipid enriched in apoptotic cells that is known to induce migration “find me” signaling followed by macrophage phagocytosis. However, intracellular signaling pathways responsible for initiation of chemotaxis and efferocytosis by LysoPC remain to be determined. Here we demonstrated that LysoPC‐mediated increased production of mitochondrial reactive oxygen species (ROS) was associated with activation of AMPK in macrophages. AMPK inhibitor, compound C or antioxidant approach diminished both migration and engulfment of apoptotic cells. Application of G2A blocking antibody did not prevent activation of AMPK, suggesting that LysoPC‐induced AMPK activation was independent from signaling initiated by G2A receptor, but due to mitochondrial ROS. Taken together, our results revealed that AMPK activation is initial step in LysoPC mediated “find me” and “eat me” signaling pathway that requires formation of mitochondrial ROS.
Resolvin E1 promotes neutrophil apoptosis and accelerates resolution of acute pulmonary inflammation
Authors: Filep Janos G. , Gjorstrup Per , El Kebir Driss
Published: June 2021

We have reported that the anti‐inflammatory pro‐resolving lipid mediator resolvin E1 (RvE1) biosynthesized from the ω‐3 polyunsaturated fatty acid eicosapentaenoic acid promotes neutrophil apoptosis in vitro. We have investigated the impact of RvE1 treatment on the resolution of inflammation in 3 murine models of neutrophil mediated pulmonary inflammation, E. coli pneumonia, E. coli peritonitis‐ and carrageenan plus myeloperoxidase‐evoked acute lung injury. Treatment of mice with RvE1 at near the peak of inflammation accelerated the resolution of established inflammation in all models. RvE1 markedly reduced neutrophil accumulation in the airways, and increased the numbers of monocytes/macrophages concomitant with increases in the number of apoptotic neutrophils and macrophages containing apoptotic bodies. RvE1 also attenuated pulmonary edema, IL‐6 production and tissue injury. Moreover, RvE1 treatment also reduced the mortality rate in the E. coli peritonitis model Coadministration of the pan‐caspase inhibitor zVAD‐fmk with RvE1 rendered animals resistant to treatment with RvE1. Our results demonstrate that in addition to blocking neutrophil trafficking, RvE1 promotion of apoptosis is critical for efficient and timely removal of emigrated neutrophils to enhance the resolution of acute lung injury and other inflammatory pathologies (Grant support: CIHR MOP‐97742).
Plakoglobin at adherens junctions after β‐catenin loss: Mechanism & biological implications in hepatocellular carcinoma
Authors: Wickline Emily Diane , Monga Satdarshan P.S.
Published: June 2021

β‐Catenin (β‐cat) is important in liver homeostasis as a part of Wnt signaling & cell‐cell adhesions, while aberrant activation is observed in hepatocellular carcinoma (HCC). We previously reported that hepatocyte‐specific β‐cat knockout mice (KO) lack adhesive defects, since its loss is compensated by increased plakoglobin (PG; γ‐catenin) at adherens junctions (AJ) over wildtype (WT) livers. Since PG is a desmosomal protein we asked if its increase in KOs might affect the junction. We saw no change in desmosomal ultrastructure (via TEM), proteins, or their association with PG, besides an increase in Plakophilin‐3. We then utilized an in vitro model to further elucidate the role & regulation of PG after β‐cat knockdown (KD). PG is unable to rescue β‐cat‐ TCF reporter activity; however, it suitably compensates for β‐cat loss at AJs as assessed by scratch‐wound assay, centrifugal assay for cell adhesion & hanging‐drop assay. PG increase is observed in HCC cells only upon decrease in β‐cat protein levels, not after blockade of β‐cat's transactivational activity. There was enhanced serine & threonine phosphorylation of PG after β‐cat KD which was abrogated by inhibiting protein kinases A (PKA) & PKG. In conclusion, PG compensates for β‐cat loss at the AJ without affecting desmosomes, but is unable to fulfill functions in Wnt signaling. Catenin‐sensing mechanism depends on β‐cat protein levels & not activity. Anti‐β‐cat therapies for HCC that affect β‐cat levels may target aberrant Wnt signaling without negatively impacting intercellular adhesion, if mechanisms responsible for PG stabilization are spared.
Desmoglein 2 ectodomain regulates intestinal epithelial cell homeostasis
Authors: Kamekura Ryuta , Nava‐Dominguez Porfirio , Hamilton Ross , Parkos Charles A. , Nusrat Asma
Published: June 2021

Intercellular junctions are integral to the formation of a functional epithelial barrier, as well as controlling intestinal mucosal homoeostasis. Critical components of intercellular junctions are desmosomes which, in the intestine are formed by two desmosomal cadherins referred to as Desmoglein 2 (Dsg2) and Desmocollin 2. It is well appreciated that under inflammatory conditions, cytokines such as IFN‐γ perturb intercellular junction protein function thereby contributing to epithelial barrier compromise. Here we report that exposure of human intestinal epithelial cells (IECs) to IFN‐γ results in increased Dsg2 protein levels. This increase was associated with cleavage of the extracellular domain of Dsg2 mediated by matrix metalloproteases. Treatment of IEC with the Dsg2 cleavage products resulted in altered epithelial homeostasis and adhesive properties, resulting in a compromised barrier function. In vivo analysis revealed increased Dsg2 protein expression in the intestinal epithelium of patients with inflammatory bowel disease. Taken together, these results indicate that Dsg2 and Dsg2 ectodomains may play an important role in intestinal epithelial homeostasis during inflammation.
From the connectome to the synaptome
Authors: DeFelipe Javier
Published: June 2021

Over the years, neuroanatomy has evolved considerably thanks to the use of classical techniques and the introduction of new procedures. The term “connectome” has recently been proposed to refer to the highly organized connection matrix of the human brain, in analogy to the human genome. However, defining how information flows through such a complex system represents so difficult a task that it would seem unlikely it could be achieved in the near future, or, for the most pessimistic, perhaps never. Circuit diagrams of the nervous system can be considered at different levels, although they are surely impossible to complete at the synaptic level. Despite the technical difficulties, by adopting appropriate strategies with the tools now available coupled with the development of huge international projects, it should be possible to make spectacular advances in unraveling brain organization, even in humans. Indeed, advances in our capacity to marry macro‐ and microscopic data may help establish a realistic statistical model that could describe connectivity at the ultrastructural level, the “synaptome”, giving us cause for optimism.
Integrating cell and tissue motion patterns during early embryogenesis: How much “Cell Migration” really occurs?
Authors: Little Charles D
Published: June 2021

The assembly of a hornet's nest is an example of an emergent biological pattern. Construction of a nest is not directly encoded in genetic or cell regulatory pathways. The architecture arises from thousands of hornets following simple instinctive rules; and cannot be reduced to the study of an individual hornet or its constituent parts.

Our recent studies show that amniotes rely on emergent patterns to a much greater extent compared to other vertebrates. For example, time‐lapse imaging data provide mounting evidence that early bird embryos engage in significantly less autonomous cellular motion compared to fish or frog embryos. In fact, we find a preponderance of collective cell/tissue behavior in birds. Our data suggest that during evolution, amniotes selected morphogenetic mechanisms in which the embryo is shaped by collectively engineering a new micromechanical state of the tissue — which generates physical displacements and folding of entire tissues and organ primordia. One of the emergent processes we study is the de novo formation of primary vascular networks, a system in which there is little or no evidence for the presence of a genetically encoded pre‐pattern. Emergent morphogenetic behavior is also required for formation of a midline heart. In amniotes the primitive heart forms out of coherent planar sheets of tissue. Our data show that heart precursors do not “migrate” from lateral positions towards the future site of the midline heart. Instead, cells of the mesodermal and endodermal layers appear to generate traction forces, and the resulting stresses, together with controlled relaxation, drives large‐scale tissue movements.
Extreme makeover – Anatomy Edition: How a paradigm shift in pedagogy reshaped an anatomy program
Authors: Wisco Jonathan J. , Stark M. Elena
Published: June 2021

Much has been said about, and speculated on, the effect medical sciences curriculum changes have had, and will continue to have, on gross anatomy pedagogy. In the ten years since major curriculum change was implemented at the David Geffen School of Medicine at UCLA, gross (and microscopic) anatomy pedagogy have transformed from isolated courses into themes integrated into systems based units. Although administrative policies provided the initial impetus for pedagogical transformation, in recent years, incorporation of clinical instructors into the laboratory experience has fostered multi‐disciplinary teaching partnerships that provide contextual learning experiences for students. The paradigm shift from dissection to prosection pedagogy, the integration of clinically relevant anatomy through radiology and acute care, the development of interactive, online learning tools, and an upgrade in classroom technology have influenced our ability to provide advanced anatomical sciences instruction throughout all four years of undergraduate medical education. We discuss our experiences of pedagogy transformation in the last decade, and how these are informing efforts to improve pre‐medical anatomy pedagogy.
Cholinergic basal forebrain circuit degeneration in Alzheimer's disease
Authors: Fahnestock Margaret
Published: June 2021

Alzheimer's disease is characterized by loss of synapses and neurons in specific areas of the brain, leading to loss of learning, memory and cognitive function. Among the most vulnerable neurons in Alzheimer's disease are basal forebrain cholinergic neurons. Degeneration of cholinergic projections to cortex and hippocampus is responsible for learning and memory deficits. Basal forebrain cholinergic neurons rely on two target‐derived neurotrophic factors, nerve growth factor (NGF) and brain‐derived neurotrophic factor (BDNF), to maintain survival, differentiation, connectivity and function. NGF and BDNF are dysregulated in Alzheimer's disease by very different mechanisms. NGF is found in the brain in its precursor form, proNGF, which accumulates in Alzheimer's disease and becomes toxic to basal forebrain cholinergic neurons. BDNF, on the other hand, is decreased in Alzheimer's disease at the transcriptional level, causing cholinergic dysfunction and synapse loss. The molecular pathways for BDNF down‐regulation have been partially elucidated, and recent work demonstrates that lifestyle changes can raise BDNF levels and rescue age‐related cognitive impairment. Nevertheless, a full understanding of the causes and mechanisms of basal forebrain cholinergic neuron degeneration in Alzheimer's disease remains a challenge.
Optimizing the gross laboratory experience: dissection group rotation and peer evaluation
Authors: Ressetar Holly Gail , Palmer Bruce
Published: June 2021

This presentation describes the use of criteria‐based assignment of medical students to gross dissection groups on a rotational basis and presents peer assessment and student feedback before and after institution of rotation. For the past 6 years, peer assessments have been utilized in our gross labs as a means for faculty to become cognizant of and address problems with student professional conduct and dissection group dynamics. Traditionally, 4 to 5 students were randomly assigned to a cadaver and students remained with the same group and cadaver the duration of the course. Data gathered from peer assessments highlighted specific areas of dissatisfaction regarding lab partner behaviors, cadaver condition and other issues that could propagate a stressful learning environment and low student morale. By instituting lab group rotation, students were assigned different partners and different cadavers before each of our 3 course blocks. Group rotation assignments were further refined by the use of a computerized database system that permitted assignments based on academic performance, assuring that each group had a mixture of strong and weak‐performing students. Lab group rotation equalizes the learning environment and creates more opportunity for peer interaction and teamwork allowing for a larger sample size for peer assessment and greater satisfaction with the gross laboratory experience.
Dissecting through interprofessional barriers
Authors: Wainman Bruce , Palombella Andrew
Published: June 2021

Interprofessional education (IPE) within health care programs has been shown to improve patient care and satisfaction, reduce clinical error rates, improve collaborative team behaviour, and diminish negative professional stereotypes. In recognizing this need for IPE as well as the universal commonality and interest in gross anatomy, an IP cadaveric dissection course was instituted at McMaster University in 2008. For the last 5 years this ten week Problem Based Learning (PBL)‐based gross anatomy course involving cadaver dissection in IP teams was offered to students in medicine, midwifery, nursing, physician assistant, occupational therapy and physiotherapy. Of 100–140 interested students twenty‐eight were randomly selected and allocated into 4 IP groups, consisting of 4–6 health professions each. Pre‐experience and post‐experience surveys consisting of the revised Interdisciplinary Education Perception Scale (IEPS) and revised Readiness for Interprofessional Learning Scale (RIPLS) were used to measure differences in attitudes and perceptions towards interprofessional education and collaboration, while qualitative analysis were used to evaluate these changes. Even though the students volunteered because of interest in an IP event, significant improvements were seen in the RIPL Subscale “Positive Professional Identity” and the IEP Subscale “Competency & Autonomy” and qualitative analysis indicated improvements in role clarity, anatomy knowledge, interpersonal facilitation and IP learning.
β‐apo‐13‐carotenone regulates retinoid X receptor transcriptional activity through tetramerization of the receptor
Authors: Sun Jian , Narayanasamy Sureshbabu , Curley Robert W. , Harrison Earl H.
Published: June 2021

Retinoid X receptor (RXRα) is activated by 9‐cis‐retinoic acid (9cRA) and regulates transcription as a homodimer or as a heterodimer with other receptors. It has been shown that RXRα self‐associates to a transcriptionally silent homotetramer in absence of 9cRA. We have previously demonstrated that β‐apo‐13‐ carotenone, an eccentric cleavage product of β‐carotene, antagonizes the activation of RXRα by 9cRA in mammalian cells overexpressing this receptor. However, the molecular mechanism of β‐apo‐13‐carotenone's modulation of transcriptional activity is not understood. Here, we investigated β‐apo‐13‐carotenone induced change in the oligomeric state of purified RXRα ligand binding domain (RXRαLBD). We also compared β‐apo‐13‐ carotenone with the RXRα antagonist UVI3003 using a Cis‐trans nuclear reporter cell assay (INDIGO) that detects 9cRA‐induced coactivator binding to the RXRαLBD. Reporter gene constructs(RXRE‐Luc) and wild type RXRα and mutants that impair the formation of RXRα tetramers (F318A) or dimers (R321A), were transfected into COS‐7 cells and luciferase activity was examined. Our data indicate that β‐apo‐13‐carotenone induces tetramerization of the RXRαLBD whereas UVI3003 had no effect on oligomeric state. INDIGO assay results demonstrated that UVI3003 significantly inhibited 9cRA‐induced coactivator binding to RXRαLBD, but β‐apo‐13‐carotenone did not. In contrast, transactivation assays using full length RXRα showed that β‐apo‐ 13‐carotenone shifted the dose‐dependent RXRα activation by 9cRA. These observations suggest that β‐apo‐13‐carotenone regulates RXRα transcriptional activity through modulating the RXRα tetramer‐dimer equilibrium.
The role of vitamin A metabolites in human and murine B cells
Authors: Gushchina Liubov , Yasmeen Rumana , Meyers Joseph , Thomas Jaisa , Benson Don , Boyaka Prosper , Ziouzenkova Ouliana
Published: June 2021

Unraveling mechanisms regulating gammopathies, abnormal immunoglobulin production is necessary to improve treatments of a number of blood cancers, such as multiple myeloma. Retinoic acid and retinaldehyde, a transcriptionally active metabolites of vitamin A, play a key role in differentiation processes. RA is produced by the aldehyde dehydrogenase‐1 family of enzymes (Aldh1a1, a2, a3). Our objective was to identify key genes regulating the cellular levels of these metabolites.

Our studies in healthy subjects’ showed that Aldh1a1 is the predominantly expressed Aldh1 enzyme in circulating B cells comprising majority of PBMC fraction. In contrast, two myeloma B cell lines, U266 and RPMI8226 lack Aldh1a1 expression. PBMC from multiple myeloma patients showed an expression profile similar to that of U266. We showed that similar to human B cells, naïve (CD19−) and committed (CD19+) splenic B cells from WT mice predominantly expressed Aldh1a1, whereas in Aldh1a1−/− mice these B cells were complete depleted of Aldh1 expression. In both genotypes B cell differentiation from CD19− to CD19+ phenotype was associated with the loss of Aldh1a1 and a2. The change in the RA production in CD19− and CD19+ cells was accompanied by changed levels of key proteins such as RARa, HoxA10, and PPARg. Our studies suggest that Aldh1 enzymes are important for regulation of Ig production and their deficiency is associated with malignant B cells.

Grant Funding Source: Nutrition (ASN)
Does beta‐carotene‐9′,10′‐oxygenase (CMO2) generate retinoic acid during embryonic development?
Authors: Spiegler Elizabeth , Kim Youn‐kyung , Quadro Loredana
Published: June 2021

Vitamin A is an essential nutrient throughout the mammalian lifecycle, especially for normal embryonic development. Most of the world relies on β‐carotene (bC), a provitamin A carotenoid, as its main vitamin A source. bC is converted to vitamin A by one of two enzymatic cleavage mechanisms: central cleavage by β‐ carotene‐15,15′‐oxygenase (CMO1), or asymmetric cleavage by β‐ carotene‐9′,10′‐oxygenase (CMO2). ~95% of bC conversion to vitamin A is attributed to CMO1, while CMO2, a mitochondrial enzyme, is thought to contribute minimally to vitamin A production in vivo. Both CMO1 and CMO2 are expressed in the developing tissues, and local bC cleavage by embryonic CMO1 can generate adequate vitamin A for normal development. When CMO1−/−RBP−/− dams were fed a vitamin A‐deficient diet during pregnancy, embryos developed gross malformations including eye defects, peripheral edema, and exencephaly. Supplementation of CMO1−/−RBP−/− dams with bC from 6.5–9.5 days post coitum partly improved the vitamin A deficiency symptoms of the double knockout embryos, despite the lack of CMO1. To determine whether bC cleavage by CMO2 contributed to this improvement, triple knockout mice (CMO1−/−RBP−/− CMO2−/−) were also generated, and analyzed under the same dietary regimen. The frequency of defects of CMO1−/−RBP−/−CMO2−/− embryos from dams fed a vitamin A‐deficient diet was similar to that observed in double‐knockout embryos. Experiments are ongoing to investigate whether the embryonic defects of triple knockout embryos can be improved by bC supplementation from 6.5–9.5 dpc. These experiments will shed more light on the role of CMO2 as a potential retinoic acid‐generating enzyme during embryonic development.

Grant Funding Source: NIH; Gates Foundation
Structure‐function relationships for enzymatic activity of β‐carotene 9′,10′‐oxygenase (CMO2)
Authors: Doerner Charles , Gong Xiaoming , Hardy Leon , Rubin Lewis P
Published: June 2021

Structure‐activity relationships of the carotenoid cleavage enzyme CMO2 have not been elucidated. Consequently, we have performed molecular simulations to determine stable 3D structures of CMO2 and correlation with protein function. Full‐length CMO2 was mutated at predicted critical residues (H226, H286, H357, E465, H574) and the mutated proteins were expressed in vitro. Functional activity was measured by quantitative lycopene metabolism in E. coli and HEK293 cells. CMO2 and mutant structures were predicted using protein threading (RaptorX) and scalable molecular dynamics simulation (NAMD) programs. RaptorX produced 10 possible 3D CMO2 structures. The best data fit was used for further modeling and simulations describing a structure containing four α‐helices and several β‐sheets. The interior of CMO2 features an opening/cleft that conforms to substrate binding/cleavage site criteria. Mutations of the selected residues to Ala(s) decreased the root mean squares deviation (RMSD) function c/w decreased CMO2 structure movement and stabilization. The bioinformatics results correspond with our finding that the expressed CMO2 mutants inhibit carotenoid metabolism. In conclusion, these results localize the catalytic region of CMO2. This work should facilitate further investigations of metabolism of specific carotenoids in vitro and in vivo.
Cell Adhesion and Signaling Pathways in Neurovascular Development
Authors: McCarty Joseph H
Published: June 2021

Precise regulation of cell‐extracellular matrix (ECM) adhesion and communication is essential for development of the neurovascular unit and blood‐brain barrier (BBB). Integrins are receptors for ECM proteins and many integrins are expressed in neural and vascular cells; however, their roles in neurovascular unit development remain mostly uncharacterized. We have analyzed roles for the integrin αvβ8, which is expressed in glial cells where is binds to the ECM‐associated forms of latent TGFβs. Ablation of αv or β8 integrin genes in glial cells leads to vascular pathologies, including abnormal angiogenesis, hemorrhage and premature death associated with neurological decline. Interestingly, when integrin gene expression is inducibly ablated in glial cells of the post‐natal brain, when endothelial cells are no longer actively proliferating and sprouting, we do not detect acute vascular pathologies. However, when we activate pathological angiogenesis in the brain by tumor implantation or vascular damage via cortical stab wounds, αvβ8 integrin is essential for blood vessel growth and BBB permeability. These data reveal essential roles for αvβ8 integrin and its latent TGFβ ligands in regulating neurovascular and BBB development.
The role of the Paf1 complex in controlling transcriptioncoupled histone modifications
Authors: Arndt Karen M. , Piro Anthony S. , Mayekar Manasi K. , Tomson Brett N. , Wier Adam D. , VanDemark Andrew P. , Heisler Lawrence E. , Gebbia Marinella , Nislow Corey
Published: June 2021

Histone modifications that are deposited during transcription elongation impact the recruitment and activities of proteins that further restructure the chromatin template. The Paf1 complex (Paf1C) functions at the intersection of transcription elongation and histone modification by associating with RNA pol II and facilitating the modification of histones. We are exploring three aspects of Paf1C function in yeast: the mechanism by which it stimulates histone H2B K123 ubiquitylation, the nature of its physical interaction with RNA pol II, and its involvement in transcription termination. We have recently described a small domain within the Rtf1 subunit of Paf1C that is necessary and sufficient for promoting H2B ubiquitylation. Using a multidisciplinary approach, we are currently investigating how this histone modification domain interacts with chromatin and stimulates histone modification. In a separate study, we have recently identified a domain within Rtf1 that tethers Paf1C to RNA pol II through an interaction with the elongation factor Spt5. This interaction ensures that the diverse functions of Paf1C are properly targeted to active genes. Finally, using high‐resolution tiling array studies, we have demonstrated broad and gene‐specific effects of Paf1C on the termination of snoRNAs, revealing genes that differ in their dependence on Rtf1‐mediated histone modifications. Funded by NIH and CIHR.
Biochemical dissection of bacterial virulence and macrophage innate immunity
Authors: Shao Feng
Published: June 2021

Many bacterial pathogens use a type III secretion system to inject virulent effector proteins into host cells. These effectors often use sophisticated biochemical strategies to manipulate host signal transduction pathway. I will present our work on three bacterial effector families, each of which defines a novel enzymatic posttranslational modification, and their functions in infection. The OspF effector from Shigella flexneri employs a MAPK phosphothreonine lyase activity to block host MAPK signaling and IL‐8 production. The CHBP/Cif family of effectors from Burkholderia pseudomallei and Enteropathogenic E. coli (EPEC) catalyze deamidation of Gln‐40 in ubiquitin and NEDD8, inactivating host ubiquitin pathway and many related cellular processes. NleE from EPEC and Salmonella typhimurium carries out a novel cysteine methylation modification on key ubiquitin‐chain sensory proteins in host NF‐kB pathway, blocking NF‐kB‐mediated inflammatory response during infection. On the host side, the inflammasome complex is believed to be important for macrophage innate immune defense against bacterial infection. I will also discuss our recent identification and characterization of the NAIP family of NOD‐like proteins (NLRs) that serves as inflammasome receptors for bacterial flagellin and also the type III secretion apparatus, which plays an important role in restricting various bacterial infections.
Assessing Student Development of Scientific Thinking Skills using the EDAT and ADAT: The Experimental Design and Analysis of Data Ability Tests
Authors: Sirum Karen , Majorczyk Alexis , Andrews Alfred
Published: June 2021

A significant challenge to measuring undergraduate students’ science thinking skills is defining science reasoning and specifically isolating the various overlapping skills. These include quantitative literacy/numeracy, visual literacy, and the sub skills required for experimental design and data analysis. To this end, we have designed and used the Experimental Design Ability Test (EDAT) and are developing a companion Analysis of Data Ability Test (ADAT). The EDAT is an open‐ended prompt used to reveal students’ ability to design a simple experiment to test a product claim (Sirum and Humburg, 2011). Student responses are scored by looking for the presence or absence of ten basic elements of experimental design. We have recently expanded the scoring rubric of the EDAT to begin to describe the different ways an expert might include these basic experimental design elements versus a novice's approach. The ADAT is a new open‐ended response instrument designed to minimize the threshold requirement for quantitative and visual literacy skills, while specifically assessing students’ reasoning with data. Similar to findings using the EDAT, the ADAT also reveals that up to 85% of undergraduate biology students at all levels have difficulty controlling variables in experimental situations. In addition, similar to previous research by others, the ADAT also reveals that even upper level students have deficiencies in fundamental correlational and proportional reasoning skills when asked to interpret a relatively simple data table (Lawson, 1978).