bluuebunny/crossref_metadata_2025 huggingface dataset:
Diverse gut microbes facilitate ingestion of dietary toxins in herbivores
Authors: Dearing M. Denise , Kohl Kevin , Dale Colin , Weiss Robert
Published: June 2021

For decades, gut microbes have been hypothesized to play a critical role in the detoxification of plant secondary compounds (PSCs) consumed by their herbivorous hosts. To test this hypothesis, we investigated whether evolutionary history of the host with PSCs shapes microbial diversity and if gut microbes facilitate ingestion of PSCs. We used populations of two species of woodrats (Neotoma lepida and N. bryanti) that have independently converged on the same toxic diet of creosote (Larrea tridentata) and compared them to populations that have never encountered creosote. Naïve and experienced populations of both species were fed either a control diet of rabbit chow or rabbit chow plus 2% extracted creosote resin. After 5 days, foregut contents were collected for microbial 16S rDNA sequencing. In addition, a subset of N. lepida was given an antibiotic treatment. The microbiota of the woodrat foregut was comprised primarily of Firmicutes (~80%) and ingestion of creosote increased the abundance of Bacteroidetes in experienced hosts but not in naïve ones. Woodrats given antibiotics did not ingest as much creosote as woodrats not given antibiotics. These results indicate that 1) the microbiota of the woodrat foregut differs compared to that from other foregut herbivores 2) the experience of the host with the diet alters microbial diversity and 3) that microbes enhance consumption of PSCs.
N‐methyl‐D‐aspartate (NMDA) Channels Regulate Apoptosis in Helicobacter pylori infection by Ammonia‐induced Calcium Permeation Mechanisms
Authors: Seo Ji Hye , Fox James G , Peek Richard M , Hagen Susan J
Published: June 2021

Background

Mechanisms that regulate epithelial cell apoptosis in Helicobacter pylori (HP) infection are not well understood. We tested whether ammonia, which is an important cytotoxin produced by HP, increases cell apoptosis by activating N‐methyl‐d‐aspartate (NMDA) channels, which are calcium‐influx channels.

Methods

MKN28 cells were transfected with a control or NMDA receptor 2B expression plasmid, creating NR2B+ and NR2B‐ cells. Each cell type was incubated with the wild‐type (WT) cag+ toxigenic HP strain 60190 or its isogenic ureB (uB) mutant, which does not produce ammonia. Calcium permeation and cell viability were tested.

Results

NR2B+ cells incubated with WT HP showed extensive calcium permeation and reduced cell viability that did not occur with uB. Additionally, NR2B+, but not NR2B‐, cells transcriptionally up‐regulated NR2B in the presence of WT but not uB. The surface epithelium from HP‐infected mice also showed a highly significant up‐regulation of NMDA channel expression.

Conclusion

Our results show that ammonia produced by WT HP transcriptionally up‐regulates NMDA channels to facilitate calcium influx, which significantly reduces cell viability. These results suggest that NMDA channels may be essential to modulate apoptosis pathways during HP infection‐mediated cancer development. This work was supported by NIH DK015681 and by Departmental funding.
Inhibition of Ca2+‐regulated exocytosis by levetiracetam in guinea‐pig antral mucous cells: role of synaptic vesicle protein 2A, SV2A
Authors: Harada Saeko , Shimamoto Chikao , Matsumura Hitoshi , Kohda Yuka , Tanaka Saori , Nakahari Takashi
Published: June 2021

Levetiracetam, an antiepileptic drug, a ligand for the SV2A, which contributes the priming of synaptic vesicles for neurotransmitter release. In this study, we investigated the effects of levetiracetam on Ca2+‐regulated exocytosis activated by acetylcholine (ACh) in antral mucous cells of guinea pigs. Because the priming dependent on ATP is the final step for releasing granular contents in the antral mucous cells. The Ca2+‐regulated exocytosis in isolated antral mucous cells was observed by videomicroscopy. Dinitrophenol (DNP) inhibits the priming resulting in a decrease in the frequency of Ca2+‐regulated exocytosis and 8‐bromoguanosine 3′, 5′‐cyclic monophosphate (8BrcGMP) enhances the priming resulting in an increase in its frequency. Levetiracetam inhibited the frequency of Ca2+‐regulated exocytosis by 40%, but it had no effects on the frequency in DNP‐treated cells. When we first added levetiracetam and then 8BrcAMP, 8BrcAMP did not enhance the frequency of Ca2+‐regulated exocytosis. In the next, when we first added 8BrcGMP and then levetiracetam, 8BrcGMP still enhanced the frequency. These results suggest that levetiracetam inhibits the priming of Ca2+‐regulated exocytosis in antral mucous cells. In conclusion, in antral mucous cells, the SV2A, which exists on the mucous granules, plays a crucial role in the priming.
Expression of tumor suppressor genes in diet‐induced liver injury: a model of the control of gene expression by gene‐specific CpG island methylation
Authors: Miszewski Susan , Green Ralph , Miller Joshua W
Published: June 2021

A methyl‐deficient diet (MDD), lacking choline and folate and low in methionine, causes liver injury in rats. We investigated the effects of epigenetic factors on hepatic gene expression in the MDD model. Weanling, male Fisher 344 rats were assigned to receive: 1) control diet for 12 weeks, 2) MDD for 12 weeks, or 3) MDD for 9 weeks followed by methyl repletion with control diet for 3 weeks (MRD). Hepatic RNA and DNA were isolated from 3 rats per dietary group. Gene expression was assessed by microarray and RT‐PCR. Gene‐specific methylation was assessed by pyrosequencing. Microarray analysis revealed ≥4‐fold increase in expression of over 150 genes in the MDD group compared with the controls. Decreased expression toward control levels was observed in the MRD group for most of these genes, and was associated with recovery from liver injury. Among the genes that followed this pattern of expression were the tumor suppressor genes, glutathione‐S‐transferase pi 1 (GSTP1) and metallothionein 2A (MT2A). Methylation patterns of gene specific CpG islands for GSTP1 and MT2A followed inverse trends, with decreased levels of methylation associated with increased gene expression in the MDD group compared with the control and MRD groups. This model of liver injury shows upregulation of tumor suppressor genes associated with diet‐induced suppression of DNA methylation.

Funding: American Cancer Society
An in vitro assay for clonogenic, high‐throughput analysis of intestinal stem cells
Authors: Gracz Adam David , Johnston Michael J , Wang Fengchao , Williamson Ian A , Wang Yuli , Balowski Joe , Sims Chris , Li Linheng , Allbritton Nancy , Magness Scott T
Published: June 2021

Recent advances in the isolation and culture of intestinal epithelial stem cells (IESCs) facilitate testing functional properties of stemness in vitro. To establish ‘stemness’ of putative IESCs that are defined by restricted gene expression signatures, single cells must demonstrate multipotency and self‐renewal. Although current in vitro assays support growth of IESCs, they are not amenable to efficient clonogenic analysis at the single cell level. Additionally, limitations of the current assay make IESC‐derived enteroid structures (bodies of crypt/villus‐like units) difficult to process for downstream molecular analysis. The development of micro‐fabricated cell culture arrays and computational image analysis provides the next technological step toward a clonogenic assay for IESCs and other somatic stem cells. Here, we show that single Sox9low‐expressing IESCs can be seeded into cell culture microwell arrays and develop into enteroids, exhibiting the same behavior as IESCs in conventional in vitro assays. Single IESCs can be separated into distinct microwells, facilitating day‐to‐day quantification of clonogenic development. We demonstrate that this microwell array technology enables efficient clonogenic analysis and provides a platform for powerful statistical analysis of the effects of small molecules on IESCs. Support: NIH R01 DK091427, NIH R03 DK089126, NC Biotechnology Center Grant.
The presumptive gastric corpus stem cell population is CD44‐positive and expands during metaplasia via increased ERK‐MAPK signaling
Authors: Khurana Shradha , Huh Won Jae , Moore Benjamin , Riehl Terrence , Stenson William F , Mills Jason C
Published: June 2021

Little is known about the epithelial stem cell (SC) of the gastric corpus, though most gastric cancers arise in the setting of altered SC biology. We have established that injection of the drug tamoxifen, leads to complete atrophy of parietal cells (PCs) by 3 days. That injury causes metaplastic gastric differentiation, characterized by an expanded, undifferentiated population within the normal SC niche in the isthmus. Here we show that CD44 labels undifferentiated, Ki67+ isthmal cells in normal epithelium that expand ≥fourfold upon tamoxifen injury. Also, untreated CD44−/− mice have reduced basal rates of proliferation. Hence, we sought to determine signaling pathways that regulate the injury induced expansion of CD44+ stem/progenitor cells. Tamoxifen causes a burst of ERK phosphorylation in the stomach within 6 hours, when PCs first begin to die. Nuclear pERK labels the expanding isthmal cells. Inhibiting pERK with U0126 blocks expansion. Stat3, which marks SC proliferation, is also highly expressed and activated by phosphorylation following tamoxifen injury. We find that CD44 binds to Stat3 to regulate cell‐cycle genes (CyclinD1) during CD44+ cell expansion. Thus, our data suggest that CD44 marks undifferentiated epithelial cells within the SC niche of the gastric unit, greatly expands on injury and is regulated by ERK. CD44 enhances SC proliferation by associating with Stat3. Our study is the first one to identify signaling pathways and molecular markers specific for regulating the presumptive SC of the corpus epithelium during homeostasis.
Changes in neuromuscular transmission in the VIP−/− mouse internal anal sphincter
Authors: Cobine Caroline Ann , Saxton Sophie N , Kaminski Rachael E , McDowall Ruth A , Duffy Aisling M , Keef Kathleen D
Published: June 2021

Vasoactive intestinal polypeptide (VIP) has long been proposed as an inhibitory neurotransmitter in the internal anal sphincter (IAS) but direct evidence for this hypothesis is limited. The present study examined the role of VIP in inhibitory neuromuscular transmission (NMT) in the mouse IAS by comparing contractile and membrane potential responses to electrical field stimulation (EFS) of nerves in wild type (WT) and VIP−/− mice. EFS with short trains of stimuli (4s) gave rise to frequency (0.1–20 Hz) dependent relaxation and hyperpolarization in WT and VIP−/−mice. Peak EFS‐induced responses were not different between mice under control conditions and in the presence of the P2Y1 receptor antagonist MRS2500 (1 μM) while they were abolished with combined MRS2500 plus the nNOS inhibitor L‐NNA (100 μM) indicating that VIP is not required for nitrergic NMT. With longer trains of EFS (5Hz, 30–60s; 20 Hz 10–30s) a more slowly developing nitrergic and purinergic‐independent response was observed in WT but not VIP−/−mice suggesting that this component is due to VIP. In WT mice this component was blocked by the VIP receptor antagonist VIP6‐28 (10 μM) further supporting this hypothesis. In conclusion, these data provide evidence that the third inhibitory neural component in the mouse IAS is due to VIP. This pathway requires higher levels of EFS and persists well beyond the period of nerve stimulation. Grant support: DK078736.
Dietary antioxidant density in usual diet improves inflammatory biomarkers in overweight postmenopausal women
Authors: Wang Ying , Yang Meng , Vance Terrence M , Lee Sang-Gil , Davis Catherine G , Chun Ock K , Koo Sung I
Published: June 2021

Total antioxidant capacity (TAC) of typical diets has been found to be associated with increased plasma TAC level and antioxidant enzyme activities. However, its relationship with long term change in inflammation biomarkers is unknown. We aimed to examine whether increased dietary TAC can improve inflammatory biomarkers in a high risk population. Forty postmenopausal, overweight, non‐smoking, but apparently healthy women aged 40–70 y were recruited for a 9‐month longitudinal study. Seven‐day food records and 12‐h fasting blood samples were collected at baseline and at the end of the observational study for dietary and plasma biomarker assessments. At baseline, no association between dietary TAC and inflammatory biomarkers was identified. Over the 9 months, the increase in dietary TAC was accompanied by an inverse change in fasting blood glucose level (p<0.01). It also had a negative partial correlation with E‐selectin level (p<0.05) when age, ethnicity, change in BMI, and changes in blood cholesterol and triglyceride levels were adjusted. When participants were divided into two groups by positive and negative changes in dietary TAC over 9 months, participants having positive change in dietary TAC had a smaller increase in MCP‐1 compared to the negative TAC change group (p<0.05). Findings suggest that modification of dietary TAC might be an effective long term strategy for improving inflammatory biomarkers.

Grant Funding Source : Donaghue Nutrition Research Program
Association between dietary patterns and renal function indicators in type 2 diabetes
Authors: Huang Meng-Chuan , Jhang Huei-Ru , Shin Shyi-Jang , Hsu Chih-Cheng
Published: June 2021

Dietary patterns have been linked to various chronic diseases, but sparse data are available for renal dysfunction in type 2 diabetes. We aimed to examine associations between dietary patterns and glycemic and renal function indicators in type 2 diabetes in Taiwan. In 2008, we obtained habitual dietary intake data using food frequency questionnaires from 702 type 2 diabetic patients recruited from the DMIDS cohort established in Taiwan. Factor scores of dietary patterns including high fat meat (meat, smoked or fried meat, seafoods), traditional Chinese (soy, root vegetables and low‐nitrogen stach, nuts)and vegetable and fish prudent pattern) were generated using principal components analysis. After adjustment for clinical and lifestyle confounders, traditional Chinese pattern scores correlated positively with hemoglobin A1c levels (p=0.005). For renal function indicators, high fat meat pattern scores correlated positively with urinary albumin‐to‐creatinine ratio (ACR) (p=0.036). Both dietary patterns, including traditional Chinese and vegetable/fish prudent dietary patterns correlated with increases in eGFR (mL/min/1.73 m2). Based on multiple food group consumption data, these findings are consistent with beneficial effects of consuming healthy foods with moderate protein levels and an adverse effect of meat intake on clinical renal function.
Decrease of Postprandial Endothelial Dysfunction by Spice Mix added to High Fat Meat Patty in Men with Type 2 Diabetes Mellitus
Authors: Li Zhaoping , Henning Susanne , Zhang Yanjun , Zerlin Alona , Thames Gail , Tseng Chi-Hong , Heber David
Published: June 2021

Background

High fat intake has been demonstrated to promote endothelial dysfunction possibly through an increase in lipid peroxidation and decrease in serum nitric oxide.

Objective

study the effect of spice mixture on malondialdehyde (MDA) production, serum nitric oxide and postprandial endothelial dysfunction measured as peripheral arterial tonometry (PAT).

Methods

Hamburger meat was mixed with and without spice prior to cooking. Twenty‐two males with type 2 DM on diet or oral medications consumed control burgers with salt only (CB) or salt and spice mix (SPB) in randomized order.

Result

Eighteen subjects completed the study. Two hours after consumption of the burger, the PAT score decreased by 9.7±21.5% for CB and increased by 18.0±42.4% for SPB. The change of PAT score after CB and SPB was significantly different (p=0.025). The postprandial concentration of glucose, insulin and triglycerides were similar in all subjects after CB or SPB. Urine MDA excretion in μmol/g creatinine was reduced by 31 percent (p<0.001) in the subjects consuming the SPB compared to the CB group. The average urine nitric oxide concentration 6 hours after consumption of burgers was 9.09±5.7 mcM/mg after CB and 12.37±7.00 mcM/mg after SB with a p value of 0.053.

Conclusion

This study demonstrates the benefits of a polyphenol‐rich spice mixture in promoting vascular health when added to cooked meats.
Students teaching students – facilitating deeper learning of anatomy?
Authors: Evans Darrell John Rhys
Published: June 2021

The success of peer teaching in medical courses relates to the ability of peer tutors and tutees to interact and communicate effectively providing an environment conducive for learning. We have introduced near‐peer teaching into our curriculum whereby more experienced fourth‐year medical students teach anatomy to first and second year medical students. Whilst this approach keeps the attributes of peer‐teaching, the benefit for the near‐peer teacher is the opportunity for them to reinforce and expand their own learning and develop essential teaching skills. Feedback from near‐peer tutors suggests that the program provides them with a better sense of what knowledge and understanding is required in anatomy at the different stages of their learning and enables them to actively use that knowledge to facilitate learning in others. First and second‐year students appeared to view the inclusion of near‐peer teachers as a positive element in their learning and something to aspire to later in the course.
The role of SOD‐2 in a mouse model of multiple sclerosis
Authors: Inoue Taeko , Majid Tabassum , Quick Ann , Pautler Robia G. , Beeton Christine
Published: June 2021

Multiple Sclerosis (MS) is a demyelinating disease of the Central Nervous System (CNS) that can result in debilitation of afflicted individuals. Oxidative stress is suspected of playing a key role in the pathogenesis of this disease; however, the mechanism is poorly understood. We hypothesized that mitochondrial superoxide plays a key role in the pathogenesis of MS and that overexpression of its scavenging enzyme superoxide dismutase‐2 (SOD‐2) would reduce disease severity. We induced experimental autoimmune encephalomyelitis (EAE), a mouse model of MS in SOD‐2 overexpressing (SOD‐2OV) and WT control mice and monitored their disease severity for 5 weeks. We found that SOD‐2OV mice showed a lower disease severity compared to their WT counterparts. At the end of the 5 weeks, mice were imaged using MRI to assess their blood‐brain barrier (BBB) permeability and we found that there was no difference in BBB leakage between genotypes indicating that BBB permeability is not critical in the development and pathogenesis of the disease. Finally, we carried out immunohistochemistry (IHC) and found that there was significantly lower immune infiltrates to be found in the spinal cords of SOD‐2OV mice compared to WT mice. In conclusion, SOD‐2 overexpression resulted in improved disease severity and lower immune infiltration in a mouse model of MS. Funding sources: RO1: NINDS NS073712 (CB), NIH/NIA R01AG029977 (RGP), NIH/NIDDK P30 DK079638‐02 PILOT PJ4 and Mitchell Foundation
Sulfur Mustard Aerosol Inhalation Injury in Rat Lungs via Fas‐mediated Apoptosis
Authors: Ray Radharaman , Andres Devon , Keyser Brian , Appell Ashley , Benton Betty , Kniffin Denise , Hamilton Tracey
Published: June 2021

We have focused on the Fas (death receptor)‐mediated pathway of apoptosis as a major mechanism of sulfur mustard (SM) inhalation injury. We examined the changes in caspase−8, −9, −3 and −6 activities in bronchoalveolar lavage fluid (BALF) cells and in soluble Fas ligand (sFasL) in BALF at 24 hours following SM exposure (3.0 mg/kg SM, 10 minutes) using a ventilated SM aerosol inhalation rat model. We observed that SM inhalation increased all four caspases in BALF cells as well as the level of sFasL in BALF. Caspase−8, −9, −3, and −6 increased 7‐, 10‐, 2‐ and 4‐fold, respectively, compared to their respective sham controls at 24 hours after SM exposure. Immunohistochemical staining in whole lung tissue showed the presence of activated caspase‐3 in SM inhalation‐exposed rat airway and the lung. These findings suggest that SM inhalation causes apoptosis in the airways and the lungs in this rat model. Observed increases in caspase‐8 and sFasL suggest their involvement in the caspase cascade signaling sequence and the Fas‐mediated pathway as seen in vitro in cultured human AEC. However, these observations need to be validated by studying the relationships between caspase‐3 and the other caspases. In conclusion, these results should be useful in determining the pathogenic mechanisms as well as therapeutic targets for SM inhalation injury. Research was funded by DTRA – Joint Science and Technology Office, Medical S&T Division.
MicroRNAs in DNA Damaging Cancer Therapy
Authors: Chowdhury Dipanjan
Published: June 2021

Efficacy of conventional cancer therapy is limited by normal tissue toxicity and by the intrinsic or acquired chemo/radio‐resistance of many tumors. Radiation and platinum‐based regimens have narrow therapeutic windows, and small increments in dosage can cause major side effects. There has been limited success in predicting tumor response to radiation/platinum‐based therapy and their usage has been largely empirical. The challenge is to develop reliable biomarkers for optimal use of these agents. Another DNA damaging agent that is being specifically used to eliminate hereditary BRCA‐deficient tumors is the inhibitor of poly (ADP‐ribose) polymerase (PARP). PARP inhibitors exemplify targeted cancer therapy. We have recently discovered that a new class of gene expression regulators, microRNA (miRNA)s down‐modulate DNA repair proteins in cancer cells. We have utilized a combination of expression profiling and functional miRNA screens to identify specific sets of miRNAs that impact DNA repair pathways and subsequently influence the efficacy of therapeutic regimens with PARP inhibitor, cisplatin and radiation. We hypothesize that these miRNAs may serve as biomarkers for cancer therapy.
Role of cancer‐associated nuclear‐retained RNA in pre‐mRNA splicing regulation
Authors: Prasanth Kannanganattu V , Tripathi Vidisha , Zong Xinying , Shen Zhen , Prasanth Supriya G
Published: June 2021

In eukaryotic cells, long ncRNAs (lncRNAs) play roles in crucial cellular processes and their aberrant expression is linked to several diseases. The cancer‐associated MALAT1 is an lncRNA that interacts with SR splicing factors, regulates SR‐protein activity and modulates alternative splicing. MALAT1 displays cell cycle‐regulated expression, with low levels during G1 and significantly elevated levels during G1/S transition. MALAT1 is required for entry into S‐phase progression, as MALAT1‐depleted human primary cells show defects in G1 to S‐phase transition. Significant population of MALAT1‐depleted cells undergoes senescence, with characteristicβ‐gal positive labeling and increased expression of senescence‐associated genes. Our results indicate that MALAT1 acts like a “molecular sponge” and titrates the functional level of SR proteins during cell cycle. This in turn facilitates alternative splicing of specific pre‐mRNAs involved in cell cycle progression.
The ‘Unskilled and unaware’ effect is linear in a real‐world anatomy setting
Authors: Finn Gabrielle Maria , Sawdon Marina A
Published: June 2021

Self‐assessment ability in medical students and practising physicians is generally poor yet essential for academic progress and professional development.

The aim of this study was to determine undergraduate medical students ability to accurately self assess their exam performance in a real‐world, high‐stakes exam setting, something not previously investigated. Medical students (n=199) participated in a self‐assessment exercise. Students predicted their exam score on the anatomy practical exam. Students’ predicted exam scores were correlated with their actual attained exam scores. Demographic data was analysed. A negative correlation was found between students’ predicted and attained exam scores. There was no relationship between the students’ entry status into medical school and self‐assessment ability or between sexes. The number of hours of additional self‐directed learning undertaken did not influence students’ self‐assessment. Our results demonstrate the ‘unskilled and unaware’ phenomenon in a real‐world, higher‐stakes and practice‐related setting. Poor performers over estimated their ability, and conversely, high achievers underestimated their performance. We present evidence of a strong, significant linear relationship between medical students’ ability to self‐assess their performance in an anatomy practical exam, and their actual performance; in a real world setting.

Grant Funding Source : Internal funding
Anatomy Knowledge: A critical Component of Clinical Care
Authors: Lazarus Michelle Denise , Chincilli Vernon M , Kauffman Gordon L
Published: June 2021

Many undergraduate medical school curricula have undergone changes resulting in reduced anatomy teaching time. We hypothesized that anatomy course development would be enhanced by understanding essential components of clinical anatomy. Surveys were administered to clinicians who were asked to rate the clinical relevance of anatomy using an 11 point likert scale. Clinicians were divided into 3 categories: Surgical (S, n = 30), procedural (P, n = 39), and non‐procedural specialist (NPS, n = 16) or primary care (NPP, n = 36). Clinicians categorized as S perceived that the role of anatomy in the clinic was more important (mean = 9.83) then other clinical groups. While each clinical group ranked anatomy as important in the clinic (mean ≥7), the NPP group's rating was the lowest (mean = 7.94). Physical exam was identified as an area of clinical care in which all specialties rely heavily on anatomy knowledge (average mean = 9.14). The role of anatomy in patient treatment and communication with colleagues were among the areas of clinical care which varied widely among the clinicians surveyed (p≤0.005), suggesting some specialty specific roles of clinical anatomy. The evidence obtained with this targeted needs assessment suggests the need for formal educational review of pertinent anatomy and will serve as the basis for courses designed to transition basic anatomical sciences to their application in the clinical setting.

Grant Funding Source: n/a
The role of Slit‐Robo signaling in Congenital Diaphragmatic Hernia
Authors: Sun Xin , Domyan Eric , Hines Elizabeth
Published: June 2021

Congenital Diaphragmatic Hernia (CDH) is a common birth defect associated with high mortality and severe respiratory deficiency in survivors. A general feature of CDH is the herniation of the abdominal tissues into the chest cavity, leading to malformation of the lung. The cellular and molecular mechanisms underlying CDH remain poorly understood. We found that mice deficient in the function of two Roundabout (Robo) receptors, Robo1 and Robo2, exhibit defects resembling CDH. Determination of the origin of these defects led to an unexpected role of Robo in the separation of foregut from the dorsal body wall, a morphogenetic process that is vital, yet rarely studied. Together, these data suggest for the first time that delayed separation of the foregut tissues from the dorsal body wall may contribute to the etiology of CDH in humans.
VEGF Receptors Identify a Multipotent Cardiovascular Progenitor Cell in Developing Hearts and Induced Pluripotent Stem Cells
Authors: Schenke-Layland Katja , Nsair Ali , Van Handel Ben , Mikkola Hanna K , Goldhaber Josh , Kahn Michael , MacLellan W. Robb
Published: June 2021

Cardiovascular progenitor cells (CPCs) were identified within developing mouse hearts by expression of Nkx2.5 and Islet 1 (Isl1). Detailed study of endogenous CPCs has been limited due to the lack of specific cell surface markers. Here, we identified cell surface markers of Isl1+ CPCs. We functionally validated these CPC markers in induced pluripotent stem cell (iPSC)‐derived CPCs. Microarray analysis of Isl1+/Flk1+ mouse CPCs identified a panel of surface markers expressed on Isl1+ CPCs. The combination of Flt1+/Flt4+ best identified and facilitated purification of Isl1+ CPCs from embryonic hearts as well as differentiating iPSCs. Selective inhibition of p300‐dependent Î2‐catenin signals using the small molecule IQ‐1 allowed in vitro CPC clonal expansion while maintaining their phenotype and multipotency. Endogenous mouse and iPSC‐derived Flt1+/Flt4+ CPCs differentiated into all cells of the cardiovascular lineage in vitro, and demonstrated robust engraftment and differentiation into mature adult cardiomyocytes in vivo. In conclusion, we have demonstrated that the combination of Flt1 and Flt4 can specifically identify endogenous and iPSC‐derived Isl1+ CPCs with trilineage cardiovascular potential. We showed robust differentiation into cardiomyocytes, smooth muscle and endothelial cells in vitro as well as post transplantation in vivo.
ER‐to‐cytosol membrane transport of pathogens
Authors: Tsai Billy
Published: June 2021

Misfolded ER proteins are transported to the cytosol and degraded by the ubiquitin‐dependent proteasome machinery. Strikingly, this ER‐to‐cytosol transport pathway is co‐opted by pathogens such as viruses and toxins during entry. How pathogens hijack this pathway to enter host cells is poorly understood, and is the focus of our research.
Timing of dessert but not portion size affects young childrenˈs intake at lunchtime
Authors: Kranz Sibylle , Huss Lyndsey Rae , Laurentz Sara , McCabe George
Published: June 2021

In most children, diet quality is low; a circumstance that might contribute to the childhood obesity problem and that might be exacerbated by increased food intake when the portion sizes increase. We determined if children modified the amount of food and energy consumed from the main course and dessert at lunchtime, when portion sizes of the main course were increased by 50% and dessert was served with versus after the main course at lunch. Food and energy intake at lunch and the consumption at the preceding snack were measured using the plate waste method to estimate the amount of food (g) consumed and the amount of energy (kcals) consumed from these foods. Descriptive statistics were used to describe the sample and study results. A mixed model analysis of variance (ANOVA) was conducted to examine the effect of portion size and timing of dessert, controlling for age, gender, classroom, study week, and interactions thereof on energy intake from the main course and dessert at lunch. Results indicated that when dessert was served after the main course, children consumed more of the main course, dessert, and both combined at the meal and portion size had no statistically significant effect. Our results suggest that the effect of the portion size of a meal component is modified by the timing of dessert.
Meta‐analysis of interaction between dietary magnesium intake and genetic risk variants on diabetes phenotypes in the CHARGE Consortium
Authors: Hruby Adela , Ngwa Julius S. , Meigs James B. , Nettleton Jennifer A. , McKeown Nicola M. ,   the CHARGE Nutrition Working Group
Published: June 2021

Little is known about whether genetic variation modifies the effect of magnesium (Mg) intake on two important diabetes risk factors: fasting glucose (FG) and insulin (FI). We examined interactions between dietary Mg and genetic variants associated with glucose (16 SNPs), insulin (2 SNPs), or Mg homeostasis and transport (8 SNPs), on FG or FI. Fifteen cohorts provided dietary, genetic, FG (mmol/L), and FI (pmol/L, ln‐transformed) data on up to 52,170 participants without diabetes. Analyses included: associations of Mg with FG or FI; associations of SNPs with FG or FI; and interactions between Mg and each SNP on FG or FI. Cohort‐level results adjusted for age, sex, energy intake, study center, and population substructure were meta‐analyzed using inverse variance‐weighted, fixed‐effect methods. Statistical significance was α=0.0015 (Bonferroni correction for 34 tests). FG (β: ‐0.012 mmol/L; 95%CI: −0.015, −0.008) and FI (−2.4% or β: −0.024 ln‐pmol/L; 95%CI −0.027, −0.020) were lower per 50 mg/day greater intake of Mg. No interaction was observed (p=0.0198–0.9364). Consistent with other studies, higher Mg intake associated with lower FG and FI. There was no evidence that genetic variants at these loci influence the association between dietary Mg and FG or FI.

Grant Funding Source: NIH/NIDDK Training Grant
Uterine physiological responses and global gene expression in ovariectomized (OVX) rats treated with soy protein isolate (SPI) or 17‐βestradiol
Authors: Ronis Martin J , Blackburn Michael , Shankar Kartik , Gomez-Acevedo Horatio , Singhal Rohit , Dunn Shannon , Badeaux Jamie , Badger Thomas M
Published: June 2021

Concerns regarding increased endometrial cancer risk have been raised in women who consume soy products as the result of the estrogenicity of phytochemical components such as the isoflavones genistein and daidzein. Female Sprague‐Dawley rats (N = 20/group) were fed AIN‐93G diets with casein or SPI as the protein source from PND30. On PND50, rats were OVX and 10/group infused s.c. with 5 μg/kg/d 17β‐estradiol (E2) to restore physiological levels. On PND64, uteri were collected, weighed and mRNA isolated for massively parallel signature sequencing (RNAseq) analysis of global gene expression profiles. Uterine wet weight was increased (P<0.05) after E2. However, SPI had no effects on uterus weight. E2 significantly regulated expression of 4,344 genes ± >2‐fold. In contrast, SPI feeding changed expression of only 457 genes, of which only 226 overlapped with E2. Many of these genes were regulated in opposite directions by E2 and SPI. 3,129 genes changed in response to E2 + SPI overlapped with E2 alone suggesting suppression of 25% of E2‐regulated genes after SPI consumption. Ki67 mRNA, a marker of cell proliferation demonstrated this pattern of response when examined by real time RT‐PCR. These data suggest SPI feeding does not produce uterine hyperplasia and actually inhibits the proliferative effects of E2 on the uterus. USDA, CRIS 6251‐51000‐007‐03S.
Interactions between XRCC3 polymorphisms and circulating folate concentrations on survival after breast cancer diagnosis
Authors: McEligot Archana Jaiswal , Ziogas Argyrios , Anton-Culver Hoda
Published: June 2021

Inadequate folate has been associated with increased DNA damage and cancer outcomes. We studied the influence of interactions between circulating serum folate levels and five tagging SNPs in the XRCC3 DNA repair gene, on overall survival after breast cancer diagnosis. Participants were post‐menopausal women diagnosed with breast cancer (n = 479) between 1994 – 1995. The Illumina BeadLab 1000 SNP genotyping system was used for genotyping. Serum folate was measured by isotope‐dilution LC/MS/MS. In the separate Cox proportional multivariate hazards models [controlled for disease stage, age at diagnosis, body mass index (BMI), parity, ER/PR status, alcohol use, vitamin use and energy intake], we found that the rs861531 XRCC3 loci was significantly (p = 0.03; HR: 1.64, CI: 1.1 – 2.5) associated with a 65% increased risk of dying. Compared to the models with the dietary biomarker and the XRCC3 loci alone, the hazards ratio for the model with both the dietary biomarker (p = 0.09; HR: 0.53, CI: 0.25 – 1.1) and the rs861531 loci (p = 0.03; HR: 1.65, CI:1.1 – 2.6) were not substantially influenced. These data suggest that circulating folate levels and XRCC3 polymorphic variant rs861531 have independent effects on overall survival after breast cancer diagnosis, with increased folate concentrations improving overall survival, while the recessive allele for rs861531 reducing overall survival after breast cancer diagnosis. Supported by NCI grant K07 CA101964
Involvement of Sp1 in Transcriptional Regulation of Atp7a During Hypoxia
Authors: Xie Liwei , Collins James
Published: June 2021

Genes with GC‐rich promoters were preferentially induced in the rodent intestine during iron deficiency. Moreover, promoters of iron homeostasis related genes (e.g. Dmt1, Dcytb) contain evolutionarily conserved Sp1 binding sites (GC‐rich sequences). The Menkes copper ATPase (Atp7a) gene was strongly induced during iron deficiency, and we previously demonstrated that Atp7a was co‐regulated with iron transport related genes by HIF2α. In this study, we sought to test the role of Sp‐like trans‐acting factors in transcriptional regulation of Atp7a. Phylogenetic footprinting revealed several conserved Sp‐like binding sites in the Atp7a promoter. These sites were mutated in a −224 bp promoter construct driving the luciferase reporter gene. Several of these sites participated in the induction of promoter activity in response to hypoxia in transfected rat intestinal epithelial (IEC‐6) cells. Moreover, phosphorylation of Sp1 increased in IEC‐6 cells exposed to hypoxia; Sp1 is known to be regulated by phosphorylation, which increases DNA binding and trans‐activation properties. Further studies will explore Sp factor interaction with the Atp7a promoter by chromatin immunoprecipitation (ChIP) assay in IEC‐6 cells and in intestine of iron deficient rats. Current data suggest that synergistic interactions between Sp1 (or a related factor) and HIF2α mediate induction of Atp7a gene expression during hypoxia.

Grant Funding Source : 1R01 DK074867
Using natural stable calcium isotopes to rapidly assess changes in bone mineral balance using a bed rest model to induce bone loss
Authors: Morgan Jennifer L. L. , Skulan Joseph L. , Gordon Gwyneth E. , Romaniello Stephen J. , Smith Scott M. , Anbar Ariel D.
Published: June 2021

Spaceflight and metabolic bone diseases disrupt normal bone mineral balance (BMB) resulting in bone loss. Bed rest, by stimulating bone loss, provides the opportunity to evaluate new methods to monitor BMB in healthy individuals suffering bone loss. Natural variations in the Ca isotope ratio occur because bone formation depletes soft tissue of light Ca isotopes preferentially, while bone resorption releases that isotopically light Ca back into soft tissue (Skulan & DePaolo, 1999). Using a bed rest model, we demonstrate that the Ca isotope ratio of urine shifts in a direction consistent with bone loss after just 7 days of bed rest, long before measurable changes in bone mineral density (BMD) occur. The Ca isotope variations are consistent with changes observed in urinary N‐teleopeptide, a bone resorption marker. Bone specific alkaline phosphatase, a bone formation marker, is unchanged. The established relationship between Ca isotopes and BMB can be used to quantitatively translate changes in the Ca isotope ratio to changes in BMD using a mathematical model. This model predicts that subjects lost 0.25 ± 0.07% (± SD) of their bone mass from day 7 to 30 of bed rest, consistent with bone loss rates from 90 day bed rest studies as measured by DXA scans. The rapid signal observed using Ca isotopes and the potential to quantitatively assess bone loss makes this technique particularly well suited for the study of bone metabolism.

Grant Funding Source: NASA Human Research Program. Dr. Morgan is supported through an appointment to the NASA Postdoctoral Program at JSC, administered by ORAU.
Conjugated linoleic acid protects against appendicular bone loss in orchidectomized middle‐aged guinea pigs
Authors: DeGuire Jason R , Lavery Paula , Mak Ivy L , Agellon Sherry , Weiler Hope A
Published: June 2021

Osteoporosis in aging men requires sex‐specific interventions. Conjugated linoleic acid (CLA) increases bone mineral density (BMD) in mice but no study has studied the effect of CLA in advanced aging in males. The objective was to assess the effects of CLA on bone loss in aging by DXA (QDR 4500A, Hologic) and micro computed tomography (μCT; SkyScan 1174). As an advanced aging model, male pigmented guinea pigs (n=40, weight: 1207.0±7.7 g) were randomized at 70 wk of age to: SHAM+Control diet, SHAM+CLA diet (1% c9,t11 CLA 80% pure), orchidectomy (ORX)+Control diet, or ORX+CLA diet. DXA and μCT scans of left tibia (T), femur (F) and L3 vertebra (L3) were performed at 16 wk. Mixed model ANOVA with post hoc Tukey's HSD was used to test for group differences in bone volume fraction (BV/TV) and volumetric BMD (Table 1) as well as trabecular number (Tb.N), thickness (Tb.Th) and separation (Th.Sp). Tb.N was significantly higher in the SHAM+CTRL (T: 0.025±0.001, F: 0.039±0.002) vs. ORX+CTRL (T: 0.019±0.001, F: 0.028±0.002; P=0.01 & 0.004). Tb.Sp of SHAM+CLA (F: 25.39±1.83) was significantly lower than ORX+CTRL (LF: 34.24±2.56, P=0.04). No differences among groups were observed for periosteal and endosteal volume, L3, Tb.Th, and T Th.Sp using μCT or any outcomes by DXA. These data suggest that CLA protects against appendicular bone loss incurred with aging. Since DXA did not reveal group differences for areal BMD it may not be sensitive enough to quantify skeletal response to some dietary interventions.

Grant Funding Source: NSERC
The Influence of home‐delivered Dietary Approach to Stop Hypertension (DASH) meals on body mass index and percent of energy needs consumed among older adults with cardiovascular disease
Authors: Racine Elizabeth F , Lyerly Jordan , Warren-Findlow Jan , Jennifer Troyer , McAuley WIlliam
Published: June 2021

Objective

To examine the impact of a home delivered DASH meal intervention, similar to the Older Americans Act Nutrition Program (OAANP) home delivered meals program, on energy balance and weight.

Methods

Data for the analysis came from a randomized control trial of home‐delivered DASH meals and medical nutrition therapy conducted from 2003–2005. Study participants (n=298) were over age 60 and had hyperlidemia or hypertension. Difference‐in‐differences (DD) models were used in estimating the effects of the home‐delivered meal intervention on BMI and percent of daily energy needs met.

Results

The majority of the study participants were white (62.1%), and were women (83.9%), had an income below 165% of the poverty level (71.5%), and were overweight or obese as indicated by a BMI ≥25 kg/m3 (76.7%). The average age was about 72. Receipt of meals did not have a significant effect on BMI or percent of daily energy needs.

Conclusion

Registered dietitians and other health care providers are encouraged to assist older adults in obtaining OAANP meals that are therapeutically designed to meet DASH guidelines.

This study was funded by the Administration on Aging
A role for Selenoprotein H in genome stability maintenance against oxidative stress
Authors: Wu Ryan TY , Cheng Wen-Hsing
Published: June 2021

Selenoprotein H (SelH) is a nuclear selenoprotein known to play dual roles in redox maintenance and transcriptional activation in the response to oxidative stress. If left unrepaired, persistent oxidative DNA damage can lead to cellular senescence and genome instability. To test an antioxidative role for SelH in genome maintenance, we generated SelH and scrambled shRNA MRC‐5 (normal) and HeLa (cancerous) cell lines and exposed the cells to DNA‐damaging agents. Here, we report that SelH knockdown sensitizes HeLa cells to treatment with hydrogen peroxide and paraquat, but not to hydroxyurea, a replication stress inducer, or to neocarzinostatin, a γ‐irradiation mimetic. Whereas both SelH and scrambled shRNA MRC‐5 cells proliferate faster when cultured in a 3% than in a 20% oxygen incubator, the growth rate is slower in SelH shRNA than in scrambled MRC‐5 cells in a 3% or in a 20% oxygen incubator. Consequently, SelH shRNA but not scrambled MRC‐5 cells reach replicative senescence at day 35 (passage 13) in a 20% oxygen incubator. Upon hydrogen peroxide treatment, cells deficient in SelH show increased induction of γH2AX and phospho‐ATM on Ser‐1981, reduced glutathione level, and translocation of Nrf2 from the cytosol to the nucleus in a dose‐dependent manner. Taken together, SelH may specifically limit oxidative DNA damage and senescence induction upon physiological oxidative stress.

Grant Funding Source : N/A
Zinc deficiency regulates TGF‐beta signaling, nuclear receptor activity, and neuronal differentiation in human neuronal precursor cells
Authors: Gower-Winter Shannon D. , Morris Deborah R. , Corniola Rikki S. , Morgan Thomas , Levenson Cathy W.
Published: June 2021

Adult stem cells that proliferate in the subgranular zone of the dentate gyrus can differentiate into neurons and integrate into the hippocampal circuitry. Consistent with previous work showing that zinc deficiency impairs neuronal stem cell proliferation, microarray analysis of hippocampal mRNA isolated from adult rats fed zinc adequate (ZA) or deficient (ZD) diets revealed the regulation of genes involved in cellular proliferation. It also identified genes involved in neuronal differentiation, including the nuclear retinoic acid receptor, RXR, doublecortin, and a TGF‐beta binding protein (p<0.05). Immunocytochemistry and Western analysis of cultured human neuronal precursor cells (NT‐2) stimulated with retinoic acid (RA) to differentiate into post‐mitotic neurons showed that ZD decreased RA‐induced expression of the neuronal markers doublecortin and TuJ1 to 40% of ZA levels (p<0.01). The TGF‐beta type II receptor, normally active during neuronal differentiation, was increased 14‐fold by RA‐treatment (p<0.001). However, this increase was reduced by 60% in ZD, RA‐treated cells (p<0.001). Furthermore, nuclear proteins, isolated from NT‐2 cells and used in a DNA binding assay showed that ZD reduces binding of RXR to DNA response elements by 50%. This was not the result of a global reduction in zinc finger proteins activity as DNA binding of the progesterone nuclear receptor PXR was not reduced in ZD cells.
Having orange juice instead of drinking water with breakfast limits postprandial fat oxidation after breakfast in normal weight adolescents and adults
Authors: Stookey Jodi , Hamer Janice , Espinoza Graciela , Higa Annie , Ng Vivian , Tinajero-Deck Lydia , Havel Peter , King Janet
Published: June 2021

Caloric beverages may promote weight gain by simultaneously increasing total energy intake and limiting fat oxidation. During moderate intensity exercise, caloric beverage intake depresses fat oxidation by 25% or more compared to drinking water. This randomized crossover study described the impact of having a caloric beverage with a typical meal on fat oxidation under resting conditions. On two separate days, healthy normal weight adolescents (n=7) and adults (n=10) consumed the same breakfast with either orange juice or drinking water, and sat at rest for three hours after breakfast. The energy content of the meal with orange juice was 210 kcal higher than the meal paired with drinking water. Both meals contained the same amount of fat (12 g). For both age groups, both meals resulted in a net positive energy balance 150 min after breakfast. Resting fat oxidation and fat balance 150 min after breakfast were significantly lower after breakfast with orange juice, however. The results suggest that, independent of a state of energy excess, when individuals have a caloric beverage instead of drinking water with a meal, they are less likely to oxidize the amount of fat consumed in the meal before their next meal.

This project was supported by unrestricted funds from Nestle Waters, by grant number 1R25HL096365‐01, and by NIH/NCRR UCSF‐CTSI Grant Number UL1 RR024131.