bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of immunodeficiency on motoneuron survival and peripheral nerve regeneration following facial nerve axotomy
Authors: Beahrs Taylor R , Sanders Virginia M , Jones Kathryn J
Published: June 2021

Facial nerve axotomy is a well‐described injury model for peripheral nerve regeneration and facial motoneuron (FMN) survival. After facial nerve transection, FMN survival levels in Rag2 KO mice (lacking functional T and B cells) are ~60% compared to ~86% in wild‐type (WT) mice at 4 week postoperative (wpo). This decrease in Rag2 KO FMN survival can be rescued to WT levels by reconstitution with CD4+T, but not CD8+ or B cells, prior to nerve transection. However, the ability of CD4+T cells to support FMN survival appears to be transient because WT FMN survival levels begin to decrease by 10 wpo, approaching Rag2 KO levels. The first goal of this study is to examine WT FMN survival at extended time points (18 and 26 wpo) to determine whether a functional immune system provides transient neuroprotection, or long‐term support for FMN survival. In addition, we will utilize a crush axotomy to evaluate functional recovery in WT, STAT6 KO (impaired Th2 response), T‐Bet KO (impaired Th1 response), and Rag2 KO mice. Based on the immune‐mediated neuroprotection observed following transection, we speculate that some or all of these immunodeficient mouse models will have impaired functional recovery and/or decreased FMN survival after crush. The specific transgenic models used in this study may also confirm the role of CD4+T cell subsets in immune‐mediated neuroprotection.

Supported by NIH grant NS40433 (KJJ & VMS).

Grant Funding Source

NIH grant NS40433
Neuroprotective effects of testosterone in two models of spinal motoneuron injury
Authors: Sengelaub Dale R.
Published: June 2021

Testosterone, a hormone typically associated with sex, aggression, and athletic performance, also has an important role in the maintenance and repair of the nervous system after injury or disease. Following induced death of spinal motoneurons remaining motoneurons atrophy, but this atrophy can be attenuated by treatment with testosterone. Partial motoneuron depletion results in decreased amplitudes of motor nerve activity, and these changes are attenuated by treatment with testosterone, providing a functional correlate to the neuroprotective effects of testosterone treatment on motoneuron morphology. Testosterone also regulates the expression of receptors for trophic factors, proteins critical for the maintenance of normal structure and function. Brain‐derived neurotrophic factor (BDNF) and testosterone have a combinatorial effect in the maintenance of motoneurons after axotomy in that dendritic morphology is supported by BDNF treatment, but only in the presence of testosterone. We have demonstrated that maintenance of trkB receptors with testosterone may be necessary to permit the trophic effects of BDNF in supporting dendritic morphology after axotomy. Together, these findings suggest that testosterone regulates neuroprotective effects on spinal motoneurons through a variety of mechanisms, and support a role for testosterone as a neurotherapeutic agent in the injured nervous system.
Therapeutic application of gene silencing MMP‐9 in a middle cerebral artery occlusion‐induced focal ischemia rat model
Authors: Zhou Changman , Hu Qin , Cheng Mingliang , Yuan Yaohua
Published: June 2021

RNA interference appears to have a great potential not only as an in vitro target validation, but also as a novel therapeutic strategy based on the highly specific and efficient silencing of a target gene. We hypothesize that MMP‐9 siRNA can be effective as an MMP‐9 protein inhibitor in a rat focal ischemia model. Male Sprague‐Dawley rats (156) were subjected to 2 h of middle cerebral artery occlusion (by using the suture insertion method)followed by 24 h of reperfusion. In the treatment group, 5 μl MMP‐9 siRNA was administrated by intracerebroventricular injection within 60 min after 2 h of focal ischemia. The siRNA transfection was demonstrated by fluorescence conjugated siRNA. Treatment with MMP‐9 siRNA produced a significant reduction in the cerebral infarction volume, brain water content, mortality rate and accompanying neurological deficits. The following were recorded: Evan's blue and IgG extravasation were reduced; the expression of MMP‐9 mRNA and protein were significantly silenced; and Immunohistochemistry and Western blot analysis revealed that the expression of MMP‐9 and VEGF were reduced while occludin and collagen‐ IV were up‐regulated in brain tissues. Our findings provide evidence that a liposomal formulation of siRNA might be used in vivo to silence the MMP‐9 gene and could potentially serve as an important therapeutic alternative in patients with cerebral ischemia.
The Role of Bicaudal‐C in Kidney Development
Authors: Wessely Oliver , Agrawal Raman , Tran Uyen
Published: June 2021

The RNA‐binding molecule Bicaudal‐C (BicC1) has been shown to regulate embryonic development in Drosophila and Xenopus. Interestingly, mouse mutants of Bicaudal‐C do not show early developmental defects, but develop polycystic kidney disease (PKD) instead. PKD is among the most common single gene diseases in humans and is the leading cause of end‐stage renal failure. It is characterized by the formation of fluid‐filled cysts in the kidney. Importantly, these cysts are thought to be caused by a defect in cell asymmetry causing kidney epithelial cells to misalign within the tubule leading to an increase of the tubule diameter.

Here we provide data that BicC1 functions by regulating the expression of Polycystin‐2 (PC2), a member of the transient receptor potential super family. Knockout of BicC1 in mice results in the formation of early onset PKD characterized by cysts along the entire length of the nephron and reduced expression of PC2 in the kidney. Molecular analyses in Xenopus showed that BicC1 and PC2 cooperate and PC2 is required for the activity of BicC1. Moreover, at the subcellular level BicC1 protein was detected in cytoplasmic foci that were positive for P‐body markers such as GW182. Based on these data we propose that the PKD phenotype caused by loss‐of‐BicC1 in mice is caused by misregulation of of PC2 at the post‐transcriptional level.
Extracellular regulation of growth factor signaling by fibrillin microfibrils
Authors: Sakai Lynn , Sengle Gerhard , Charbonneau Noe L. , Carlberg Valerie M.
Published: June 2021

Fibrillins regulate large latent complexes of TGFβ through interactions with Latent TGFβ Binding Proteins (LTBPs). These interactions are mediated by a single region in fibrillin‐1 that contains the first hybrid domain. In Fbn1 mutant mice, TGFβ signaling is activated, demonstrating that fibrillin microfibrils regulate TGFβ signaling in vivo. Fibrillins also interact directly with the prodomains of Bone Morphogenetic Proteins (BMPs) and target and sequester BMP‐4, BMP‐5, and BMP‐7 into the extracellular matrix. In the skeletal muscle of Fbn2 null mice, BMP signaling is activated, and skeletal muscle is poorly differentiated. These studies indicate that fibrillin microfibrils control BMP signaling in vivo. In order to investigate the molecular mechanisms underlying the regulation of growth factor signaling in more detail, we have generated two additional Fbn1 mouse models. Investigations of mice in which fibrillin‐1 is truncated and eGFP‐tagged will be discussed. This "gain of function" mouse model will be compared with Fbn1 null mice. In addition, the effect of deleting the first hybrid 1 domain in fibrillin‐1 on TGFβ signaling will be reported.
Integrating medical histology and physiology in an organ systems approach
Authors: Heidger Paul M. , Schmidt Gregory A. , Schmidt Thomas J.
Published: June 2021

Within the first‐year medical curriculum at Iowa, structure/function concepts formerly treated in separate histology and physiology courses are fully integrated within an organ systems course (Human Organ Systems, HOS). A core of didactic lectures is amplified by a comprehensive virtual and optical histology laboratory, and by selected virtual laboratory demonstrations in physiology. Each organ system bloc is introduced by lectures that provide the structural foundation upon which physiologic and clinical concepts are developed. Faculty are drawn from both basic science and relevant clinical departments. HOS is offered concurrently with other basic science courses, including medical neuroscience, and the semester following medical courses in gross anatomy, cell biology, and biochemistry. This provides ample opportunity for integrating and correlating concepts across several disciplines and levels of biologic organization. Computerized exams cover both structure/function concepts and histologic imaging. The course, as it has evolved over the past twelve years, is enthusiastically received by both students and faculty, with integration of structure/function/clinical relevance being cited annually by students as outstanding.
Teaching Histology Dispersed Throughout a Theme Based Medical Curriculum
Authors: Mazurkiewicz Joseph Edward
Published: June 2021

Fifteen years ago the Albany Medical College adopted a concept and organ system Theme‐based curriculum. As a result of the restructuring, discipline‐based courses, such as Histology, Biochemistry, Physiology and Anatomy were "disarticulated" and the content from each course was realigned into separate themes that fostered vertical integration, e.g., the cell biology, anatomy, histology, biochemistry and physiology of a particular was presented for an organ system. While at first there was a perceived loss of the traditional, horizontal integration that necessarily flows from a discipline based course, a net advantage for the education of medical students was realized as the content in the new themes was refocused on a specific organ system. Histology was dispersed throughout the first year and repurposed in the new setting. It serves as a morphological substrate mediating the biochemistry and physiology of an organ and is taught in relation to cell biology. Understanding the structural organization of cells within tissues and organs is an essential prerequisite for understanding how organs function. The histology material relevant to a particular theme is thus presented in an integrated context in which the histology is complemented by pertinent biochemical, physiological and anatomical information. Structure and function are considered to be on a continuum.
Simvastatin Increases Endothelial Nitric Oxide Synthase Expression in Cultured Endothelial Cells Preconditioned with Steady Laminar Flow
Authors: Rossi Joanna , Rouleau Léonie , Tardif Jean‐Claude , Leask Richard L
Published: June 2021

Introduction

Statins (HMG‐CoA reductase inhibitors) are known to have benefits in vascular biology beyond lipid reduction. It has been reported that statins can elevate the expression of endothelial nitric oxide synthase (eNOS) in cultured endothelial cells; however, it is not known whether this increase is conserved under hemodynamic stimulation. Methods and

Results

Human abdominal aortic endothelial cells were pre‐conditioned with fluid shear stress (1, 10 or 20 dynes/cm2) for 6 h. Without stopping the perfusion, control vehicle, simvastatin or simvastatin with mevalonate were added to the perfusion media and the flow experiment was continued for 24 h. As expected, eNOS mRNA and protein increased with increasing levels of fluid shear stress. Treatment with 1 or 10 µM of simvastatin further elevated eNOS mRNA and protein. Co‐incubation with mevalonate, a precursor to cholesterol synthesis, eliminated the effect of the statin, but had no effect on shear induction of eNOS. This suggests that the effect of statins on eNOS expression is conserved under flow and that the mechanism in which simvastatin induces eNOS is through inhibition of HMG‐CoA reductase.

Conclusions

Simvastatin enhances eNOS expression in cultured endothelial cells pre‐conditioned with steady laminar flow through inhibition of HMG‐CoA reductase. These results may explain the benefits of statins in the clinic beyond lipid reduction.
EGFL7 regulates vascular remodeling in vivo
Authors: Nichol Donna , Durrans Anna , Bambino Kathryn , Fitch Mike , Stuhlmann Heidi
Published: June 2021

Egfl7 encodes a secreted protein that is part of the interstitial extracellular matrix. Its embryonic expression is restricted to the sites of mesodermal precursors of angioblasts, the vascular endothelium in the embryo proper and the yolk sac. In mice that lack Egfl7, 50% die in utero of unknown causes. Because loss‐of‐function studies have not provided a clear role for this factor, we generated EGFL7 transgenic mice to elucidate its function in vivo. In these mice, EGFL7 is overexpressed in endothelial and hematopoietic cells, under the control of the Tie2 promoter. EGFL7 transgenics are both viable and fertile; however, at E12.5 they show hemorrhaging and vascular remodeling defects, which are accompanied by a lower than expected Mendalian ratio. At E10.5, EGFL7 transgenics exhibit vessel fusion and aberrant endothelial cell clusters in the head vasculature that is not apparent in wild types. At E12.5, transgenics show enlarged vessel lumen and an impairment in vascular smooth muscle cell recruitment. Remodeling defects are also evident in other vascular beds. 20% of E12.5 yolk sacs show similar defects to those observed in the head. Likewise, post‐natal transgenic retinal vasculature exhibits remodeling defects and an increase in vascular coverage. Together, our gain‐of‐function studies show that EGFL7 controls vascular remodeling in several vascular beds in vivo, uncovering a novel role for EGFL7.
Enhanced endothelial cell senescence by lithium‐induced matrix metalloproteinase‐1 expression
Authors: Mao Catherine D , Struewing Ian T , Barnett Corey D , Durham Samuel N
Published: June 2021

Endothelial cell (EC) senescence and dysfunction occurring after chronic injury and/or inflammation are highly associated with development and progression of cardiovascular diseases. However the factors involved in the establishment of EC senescence remain poorly understood. We have previously shown that lithium, an inhibitor of GSK3β and activator of the Wnt/β‐catenin signaling pathway, was inducing a G2/M cell cycle arrest and a cell‐senescent phenotype in EC. Herein, we show that lithium induces a rapid and pronounced up‐regulation of the matrix metalloproteinase (MMP)1, an inflammation and senescent‐cell marker, at the mRNA and protein levels. In contrast, the up‐regulation of two other senescent‐cell markers is either moderate (IL8) or delayed (PAI1). Moreover, this striking up‐regulation of MMP1 by lithium is specific among other MMPs as the expression of MMP2 and MMP14 are slightly increased and decreased respectively. This lithium effect is independent of GSK3β inhibition as both the expression of the kinase dead‐GSK3β and of GSK3β‐siRNAs fail to increase MMP1 expression while increasing IL8 mRNA expression. Interestingly, the exogenous addition of activated MMP1 is able to increase the number of EC positive for the SA‐β‐galactosidase marker with or without lithium treatment, suggesting that MMP1 participates in the establishment and/or maintenance of the EC‐senescent phenotype. Grant support: HL‐68698.
Proteolytic shedding of integrin beta 2 promotes macrophage resolution of inflammation
Authors: Raines Elaine W. , Gomez Ivan , Tang Jingjing , Vaisar Tomas , Kassim Sean , Yan Wei , Heinecke Jay , Harlan John M. , Wilson Carole L.
Published: June 2021

While the contribution of integrin beta 2 to leukocyte recruitment during inflammation is well established, the potential importance of soluble integrin beta 2 heterodimers in physiological fluids to the inflammatory response is unknown. This study demonstrates metalloproteinase shedding of integrin beta 2 heterodimers from the surface of mouse macrophages both in vitro and in vivo. Soluble integrin beta 2 is primarily released as a heterodimeric complex with alpha M, and this complex retains its ability to bind ICAM‐1. In the thioglycollate model of peritonitis, levels of soluble integrin beta 2 are elevated at times when macrophages are exiting the peritoneum and migrating to draining lymph nodes. In vivo inhibition of metalloprotease‐mediated shedding is sufficient to prevent macrophage efflux by greater than 80% and to specifically impede the loss of macrophage integrin beta 2 from the cell surface. However, disruption of integrin beta 2 substrate interactions with antibody 2E6 can reverse 50% of the metalloprotease blockade of macrophage efflux, and thus establishes that proteolytic cleavage of macrophage integrin beta 2 during the resolution of inflammation is critical to promote macrophage exit.
Translesion DNA synthesis by replicative‐like polymerases
Authors: Yang Wei , Wang Feng
Published: June 2021

Translesion DNA synthesis (TLS) by Y‐family polymerases has been well studies in recent years. These enzymes differ from replicative polymerases by possessing a spacious pre‐formed active site. They can physically accommodate a variety of DNA lesions and facilitate their bypass. Each Y‐family DNA polymerase has a unique binding pocket for the replicating base pair and thereby has preference for specific lesions to bypass or distinct non‐Watson‐Crick base pairs to make. Interestingly, several B‐family DNA polymerases are involved in translesion and mutagenic DNA synthesis, for example E. coli pol II and eukaryotic pol zeta (Rev3‐Rev7). According to amino acid sequence and three‐dimensional structure, these TLS polymerases are highly similar to the replicative polymerases in the same family. It is so far unknown what makes these B‐family DNA polymerase mutagenic and capable of TLS. I will present our recent structural and biochemical analyses of E. coli pol II, which shed light on the mechanism for a replicative‐like polymerase to carry out TLS.
Insulin accelerates global and mitochondrial protein synthesis rates in neonatal muscle during sepsis
Authors: Orellana Renan A , Gazzaneo Maria C , Wilson Fiona A , Nguyen Hanh V , Suryawan Agus , Almonaci Rosemary , Davis Teresa A
Published: June 2021

In neonatal pigs, sepsis decreases protein synthesis in skeletal muscle by decreasing translation initiation. However, insulin stimulates muscle protein synthesis despite persistent repression of translation initiation signaling. To determine whether the insulin‐induced increase in global rates of muscle protein synthesis during neonatal sepsis involves an increase in protein synthesis in the mitochondria, neonatal pigs (n=16) underwent cecal ligation and puncture or sham surgery and were pair‐gavage fed for 5 days. Pancreatic‐substrate clamps were performed to achieve fasting or refed insulin levels and fractional protein synthesis rates and translational control mechanisms were examined in muscle. CLP increased IL‐8 and CRP, but not TNF‐α, and reduced weight gain. In fasted pigs, CLP reduced global and mitochondrial fractional protein synthesis in muscle. Raising insulin increased global and mitochondrial fractional muscle protein synthesis rates in sham and CLP animals, but increased eIF4G‐eIF4E association in shams only. The results suggest that mitochondrial dysfunction contributes to the sepsis‐associated decrease in basal protein synthesis rates in skeletal muscle, which may be ameliorated by insulin stimulation. NIH AR44474, NIH AR51563, NIH HD41648, and USDA 58‐6250‐6‐001.
Decreased insulin sensitivity due to continuous nutrient administration in neonatal pigs
Authors: Stoll Barbara , Puiman Patrycja J , Benight Nancy , Bauchart Caroline , Burrin Douglas G
Published: June 2021

Chronic TPN compared to intermittent formula feeding has been shown to induce hepatic insulin resistance and steatosis in neonatal pigs. We hypothesized that the route of feeding (IV vs enteral) rather than the nature of the diet (elemental vs polymeric) or the feeding regimen (continuous vs intermittent) had contributed to the outcome. Neonatal pigs received one of four feeding regimen for 10‐14d: elemental diet continously IV (TPN), or intragastrically (CEN), or intermittently intragastrically (IEN), or a milk‐based formula intermittently intragastrically (FORM). At the end of the study, insulin sensitivity was examined using hyperinsulinemic‐euglycemic clamp technique. The glucose infusion rates required to maintain fasting blood glucose levels were not different between TPN and CEN. IEN was significantly higher than the former and tended to be lower than FORM. Liver weights were 46% higher in TPN compared to the other groups. Hepatic triglycerides (TG) were not different between TPN and CEN, and higher than in IEN and FORM which were similar. Conclusion: When given continuously, the route of elemental nutrient administration does not affect insulin sensitivity or hepatic TG. Thus, the pattern rather than the route of nutrient admininistration appears to influence insulin sensitivity.
Elevated plasma folate in older adults is associated with more pronounced evidence of vitamin B12 deficiency, including high homocysteine and methylmalonic acid and low holotranscobalamin
Authors: Miller Joshua W. , Garrod Marjorie G. , Allen Lindsay H. , Haan Mary N. , Green Ralph
Published: June 2021

Recent reports based on NHANES data showed that in older adults exposed to folic acid fortification, the combination of low B12 and elevated folate is associated with higher homocysteine (Hcy) and methylmalonic acid (MMA) and higher odds ratios for cognitive impairment and anemia than the combination of low B12 and non‐elevated folate. These findings await confirmation in other populations. We compared indicators of B12 status and cognitive function among elderly Latinos (Sacramento Area Latino Study on Aging: n=1535, age≥60y) with elevated and non‐elevated plasma folate. Subjects were divided into 4 groups based on plasma B12 (< or ≥148 pmol/L) and folate (≤ or >45.3 nmol/L). Hcy, MMA, holotranscobalamin (holoTC), holoTC/B12 ratio, modified mini‐mental state examination (3MSE) and delayed recall scores were compared among the groups. Hcy and MMA were highest and holoTC and holoTC/B12 ratio were lowest in individuals with low B12/elevated folate (n=22) compared with all other groups (p≤0.003). No differences in cognitive function scores were observed between the low B12/elevated folate group and the other groups. Low B12 is associated with more pronounced metabolic evidence of B12 deficiency when folate is elevated than when folate is not elevated. These data should be considered when assessing the costs, risks, and benefits of folic acid and B12 fortification programs.
Household Food Security and Sexual Behaviors among Adolescents in Tanzania
Authors: Cordeiro Lorraine Shirley , Levinson James , Wilde Parke , Pinderhughes Ellen
Published: June 2021

This study examined the association between household food security status and adolescent sexual behavior in Tanzania. This study found that cumulative sexual risk was significantly and negatively associated with household food security, with a modest decrease in the number of reported sexual behaviors for every unit increase in dietary diversity, after controlling for socioeconomic status and other covariates. Significant gender differences in sexual behaviors were observed in this sample, with a greater proportion of highly food insecure males than females reporting that they ever had sex, were currently involved in a relationship with an actual or potential sexual partner, and were more likely to have engaged in three or more sexual risk behaviors. However, female adolescents from highly food insecure households appeared to be at greatest risk for HIV infection, based on their reported lack of knowledge about HIV and preventive measures. Peer behaviors, family relations, and perceptions about sexual activity greatly influenced the sexual practices of adolescents in this sample. This study suggests that interventions seeking to reduce sexual risk behavior and prevent HIV infection among adolescents should target youth using multiple criteria, including but not limited to the food security status ‐ and by association economic status ‐ of their households.
Catalytic Mechanism of Eukaryotic Selenocysteine Synthase
Authors: Xu Xue‐Ming , Ganichkin Oleg M. , Carlson Bradley A , Gladyshev Vadim N , Wahl Markus , Hatfield Dolph L
Published: June 2021

The biosynthetic pathway for Sec has been established in the three domains of life, prokaryotes, archaea and eukaryotes. Mammalian Sec synthase (SecS) uses O‐phosphoseryl‐tRNA[Ser]Sec as a substrate. We have found that SecS does not dephosphorylate free O‐phospho‐L‐serine. Based on the crystal structure, we have made several mutants of this enzyme, SecSQ105E, SecSR313S, and SecSR313E, and they all showed corrupted SecS activity. These residues are strictly conserved in SecS orthologs and function to coordinate the phosphate but are lacking or variant in related enzymes. The data suggested that a phosphate loop accommodates the alpha‐phosphate moiety of O‐phospho‐L‐seryl‐tRNA[Ser]Sec and, after phosphate elimination, binds selenophosphate to initiate attack on the proposed aminoacrylyl‐tRNA[Ser]Sec intermediate. The activity profiles of mechanism‐based inhibitors were also obtained and provided additional insights into the reaction mechanism of SecS. This work was supported by Grant WA1126‐2, the Max‐Planck‐Society, the Intramural Research Program of the NIH, NCI, CCR and by NIH grants to VNG.,
Subcellular localization of carboxylesterase‐4 in rat liver cells and its role as neutral cholesteryl ester hydrolase
Authors: Ghosh Snigdha , Parathath Sajesh , Fisher Edward A , Harrison Earl H
Published: June 2021

The rat carboxylesterases, ES‐2 (serum esterase), ES‐3 (pI 5.6 esterase), ES‐4 (pI 6.2/6.4 esterase), ES‐10 (pI 6.0/6.1 esterase), and ES‐15 (pI 5.0/5.2 esterase) comprise a multi‐gene family, and function in hydrolysis of a variety of ester‐ and amide‐ containing chemicals to their respective free acids. Using realtime PCR, in the rat hepatic cell line McArdle‐RH7777 (McA) we observed ES‐4 mRNA had the highest level of expression compared to ES‐2 and ES‐3, while ES‐10 was not detectable. The subcellular location of ES‐4 in McA cells was investigated using confocal microscopy. ES4 co‐localized with ER Tracker dye, a maker for the endoplasmic reticulum (ER). Immunohistochemical studies with rat liver demonstrated the presence of ES‐4 within hepatocytes. ES‐4 also functions as a rat hepatic cholesteryl ester hydrolase. McA cells overexpressing ES‐4 showed decreased cholesteryl ester (CE) levels compared to control cells indicating that ES‐4 can hydrolyze CE in intact cells. In cells where ES‐4 levels were suppressed by 75% using siRNA there were increased CE levels. Confocal microscopy, using Oil Red O and ES‐4 antibodies, revealed areas of association of ES‐4 with the CE droplets. The results show ES‐4 is expressed in hepatocytes and specifically in endoplasmic reticulum. ES‐4 is directly associated with CE droplets and functions as cholesteryl ester hydrolase. Supported by NIH‐DK044498.
Perception of breastfeeding difficulty experienced by women who are obese, have large breasts or both by those who care for newly delivered women in Denmark
Authors: Rasmussen Kathleen M. , Katz Karin A. , Nilsson Ingrid
Published: June 2021

Women with large breasts often need extra support for breastfeeding (BF). Maternal obesity is associated with short duration of BF, and many but not all obese women have large breasts. To determine if health professionals who support BF women can distinguish between large breasts and obesity as obstacles to BF, we conducted a mail survey of 242 Danish health professionals. We assessed the respondents' ability to identify large breasts and obesity with a series of silhouettes. The survey respondents rated the difficulty of initiating BF as greater (P < 0.0001) than of continuing breastfeeding for women with large breasts and/or obesity. They rated these difficulties as lowest for women with large breasts, higher for obese women and highest for obese women with large breasts (P < 0.0001). In regression analyses, the difficulty ratings for these 3 types of women were significantly related in a complex manner to the respondents' assessment of large breasts, age, body mass index, BF experience and type of training. These findings indicate the importance of recognizing and treating large breasts and maternal obesity as separate obstacles to successful BF. They also suggest that the development of treatments to reduce these obstacles should be designed to account for characteristics of the healthcare provider. (Funded in part by a grant from Rawlings Cornell Presidential Research Scholars to KAK.)
Dose‐ranging effects of c9, t11 vs t10, c12 conjugated linoleic acid on body composition and serum lipids in hamsters
Authors: Liu Xiaoran , Wakefield Andrew P , Joseph Shama V , Aukema Harold M , Jones Peter JH
Published: June 2021

The objective of this study was to examine dose ranging effects of c9, t11 and t10, c12 isomers of conjugated linoleic acid (CLA) on body composition and serum lipids in hamsters. Male Golden Syrian hamsters (n=105) were randomized to seven groups that were fed semi‐purified atherogenic diets containing 0.25% cholesterol and 5% dietary fat, and further supplemented with treatments (0 control; 1, 2, 3% of c9, t11; 1, 2, 3% of t10, c12) for 28d. Compared with control, 1% and 3% t10, c12 treatment groups had lower (p=0.0001) food intakes, with all three doses of t10, c12 lowering (p<0.0001) body fat mass (g). Groups fed 1%, 2% t10, c12 treatments possessed higher lean mass (g; p=0.0006) compared to control and 1, 2, 3% c9, t11 treatment groups. However, neither body weights, nor serum HDL or triglyceride levels differed across treatment groups. The 2 and 3% t10, c12 groups exhibited higher (p<0.0001) cholesterol and LDL‐C levels compared to control or other treatment groups. Taken together, 1% t10, c12 CLA is an effective agent to lower fat mass and increase lean mass without altering circulating lipid levels as observed with 2% and 3% t10, c12. This study was sponsored by Advanced Foods and Materials Network, Canada.
Reduction of the glycemic index by a Novel Viscous Polysaccharide when added or incorporated into commonly consumed foods.
Authors: Jenkins Alexandra , Kacinik Veronica , Lyon Michael , Wolever Thomas , Vuksan Vladimir
Published: June 2021

Background/Objectives

Reductions of postprandial glucose levels have been demonstrated previously with the addition of a novel viscous polysaccharide (NVP) to a glucose drink and standard white bread. This study explores whether these reductions are sustained when NVP is added to a range of commonly consumed foods.

Subjects/Methods

Ten healthy subjects (4M, 6F; age 37.3 ± 3.6 y; BMI 23.8 ± 1.3 kg/m²), participated in an acute randomized controlled study. The glycemic response to cornflakes+milk (Cornfl), rice (Rice), yogurt (Yog), a frozen turkey dinner (Turk) with and without 5g of NVP sprinkled on the test meal was determined. In addition, 3 granolas with different levels of NVP , three control white breads, and one white bread and milk were also consumed. Capillary blood samples were taken fasting and at 15, 30, 45, 60, 90 and 120 min after the start of the meal. To quantify the reduction in glycemia the glycemic index (GI) was calculated.

Results

Addition of NVP reduced blood glucose response irrespective of food (p<0.01). The GI of Cornfl, Cornfl+NVP, Rice, Rice+NVP, Yog, Yog+NVP, Turk, Turk+NVP was 83, 58, 82, 45, 55 ,41, 44, and 38 respectively. The GI of the control granola, and granola with 2.5 and 5g of NVP were 64, 33, and 22 respectively.

Conclusion

Sprinkling or incorporation of NVP into a variety of different foods is highly effective in lowering the GI of a food.
IL‐19 reduces VSMC activation by regulation of mRNA binding proteins and reduction of inflammatory gene expression
Authors: Cuneo Anthony , Herrick David , Autieri Michael
Published: June 2021

Many vascular diseases are inflammatory in nature. Interleukin‐19 (IL‐19) is a recently described Th2, anti‐inflammatory cytokine. We have previously reported that IL‐19 is induced in VSMC by inflammatory cytokines and in arteries by injury. IL‐19 is anti‐proliferative and anti‐restenotic for VSMC. The purpose of this study is to determine the mechanism of these effects. IL‐19 reduces inflammation‐stimulated expression of proliferative and inflammatory gene proteins, including Cyclins B and D, CDK, IL‐8, and COX2. Importantly, IL‐19 transiently reduces expression of HuR protein and mRNA, a stabilizing inflammatory gene mRNA binding protein. Actinomycin D transcription blockade demonstrated that IL‐19 treatment reduced abundance of these mRNAs to 50‐60% of untreated controls. (P<0.001 for all). The mRNA stabilizing function of HuR is linked to its phosphorylation and cytoplasmic translocation. IL‐19 reduces HuR cytoplasmic translocation, PKCa activation, and subsequent phosphorylation of HuR. Together, these data indicate that one potential mechanism whereby IL‐19 inhibits VSMC activation is by a reduction in HuR expression and function.
Anti‐myeloperoxidase antibodies rapidly induce α4 integrin‐dependent glomerular neutrophil adhesion
Authors: Hickey Michael , Kuligowski Michael , Bourges Dorothee , Lo Cecilia , Kitching A. Richard
Published: June 2021

Despite the fact that anti‐myeloperoxidase antibodies (anti‐MPO) have been shown to promote leukocyte adhesion in flow‐based assays in vitro and in postcapillary venules in vivo, their role in promoting adhesion in the glomerular vasculature is less clear. We used renal intravital microscopy to examine glomerular leukocyte adhesion induced by anti‐MPO. In mice pretreated with LPS, 50 μg of anti‐MPO induced LFA‐1‐dependent adhesion in glomeruli. In concert with this finding, in mice pretreated with LPS, ~75% of circulating neutrophils bound anti‐MPO within 5 min of intravenous administration. However, even in the absence of LPS pretreatment, ~50% of circulating neutrophils bound anti‐MPO, a response not seen in MPO−/− mice. In addition, a higher dose of anti‐MPO (200 μg) induced robust glomerular leukocyte adhesion in the absence of LPS pretreatment. The latter response was β2‐integrin‐independent, instead requiring the α4‐integrin, which was upregulated on neutrophils in response to anti‐MPO. These data indicate that anti‐MPO antibodies are capable of inducing glomerular leukocyte adhesion via multiple pathways, with lower doses only inducing adhesion in mice receiving an infection‐related stimulus, and higher doses being capable of inducing responses in the absence of an additional inflammatory stimulus, via alternative adhesion mechanisms.

Supported by the NHMRC (Australia) & Genzyme
Increased oval cell response and fibrosis in beta‐catenin null livers after long‐term DDC exposure
Authors: Thompson Michael D , Monga Satdarshan S
Published: June 2021

An oval cell response, or ductular reaction, occurs in the mouse liver following DDC‐induced liver injury. We previously reported a potential role for β‐catenin in oval cell induction and expansion. After short term exposure (2‐4 weeks) to DDC, β‐catenin knockout liver had less A6‐positive oval cells than wild type liver. To examine the role of β‐catenin in the response to long‐term injury, we exposed WT and KO mice to DDC for 5 months. The livers from these animals were examined histologically to examine the extent of biliary injury and oval cell response. At 5 months in both groups of animals we observed the emergence of cells with scant cytoplasm and oval‐shaped nuclei, but this response was more dramatic in the KO. We utilized the oval cell marker A6 to compare the response between the two groups. Contrary to short‐term exposure (<4wk), KO liver harbored significantly more A6 positive cells than WT. This coincided with more fibrosis in the KO than observed in WT liver. We also observed nodular formation upon macroscopic examination of the KO liver. These likely indicate continued expansion and lack of differentiation of oval cells in this model. In sum, these findings indicate diverse roles for Wnt/β ‐catenin signaling during oval cell response in mice.
Regulation of glycolysis by ATP citrate lyase is supported by its selective, concordant expression with enolase in brain tumors
Authors: Beckner Marie E. , Pollack Ian F. , Hamilton Ronald L. , Kant Jeffrey A.
Published: June 2021

ATP citrate lyase (ACLY) cleaves citric acid released from inactive mitochondria to moderate cytosolic levels. Breakdown of citric acid, a regulator of phosphofructokinase 1 in glycolysis, putatively permits liberation of invasive, hypoxic tumor cells from vascular removal of acid. Previously, we found increased ACLY and glycolytic enzymes, including enolase (ENO1), in pseudopodia of brain tumor (glioblastoma) cells. Inhibition of ACLY with hydroxycitrate suppressed (p<0.05) glycolytic glioblastoma cell migration, clonogenicity and brain invasion (unpub). Queries of NIH's REMBRANDT brain tumor database showed decreased survival (p<0.01) for patients with 2X increased ACLY or ENO1 expression in all gliomas. Concordant increased ACLY & ENO1 expression was found in 97 glioblastomas using Affymetrix REMBRANDT data and all expression levels correlated using RQ‐PCR on 21 glioblastomas at the Univ of Pittsburgh (p<0.001). Correlation for ENO1 expression with ACLY was greater than with genes for carbonic anhydrases, monocarboxylate transporters, lactate dehydrogenases, HIF1A and 3 growth factors. ACLY's control of glycolysis via citric acid explains its negative survival impact. Targeting ACLY should suppress glycolysis in tumors. REMBRANDT, http://rembrandt.nci.nih.gov. Walter L. Copeland Fund for Cranial Research of The Pittsburgh Foundation.
Cellular Senescence and Remodeling of Adult Ventricular Myocyte (AVM) in Primary Culture
Authors: Liu Shi Jesse , Liu MeeiYueh G
Published: June 2021

AVM were considered terminally differentiated, which limits recovery after injury. AVM death during cardiac aging was suggested to involve cellular hypertrophy, apoptosis and necrosis. In vitro studies of AVM were limited by a short average life span in culture (~4 weeks). Additionally, the temporal changes in individual AVM during senescence have not been characterized. Thus, this study is to investigate cellular senescence in primary culture of AVM, isolated from young adult rat hearts. AVM were maintained in antibiotic‐ and antimycotic‐free M199 culture medium with 2% fetal bovine serum (refreshed every 4‐6 days) in an incubator with 5% CO2 and 95% air at 37°C for 15‐20 weeks. The growth of AVM was monitored with video microscopy and characterized with immunofluorescence staining of cardiac troponin I, connexin 43, atrial natriuretic peptide and AnnexinV+ propidium iodide in some experiments. Results showed that AVM retained myofilaments with spontaneous contracting activity and underwent hypertrophy and continuously remodeling for cell‐cell contact to form contracting fibers. Some AVM were able to regenerate to repair injury and reproduce occasionally new cells throughout the culture period. Furthermore, AVM death during senescence was inconsistent with apoptosis. In conclusion, AVM in long‐term culture can be valuable to studies of cardiac cell senescence. (Supported by UAMS departmental funding)
Amyloid and prion structures
Authors: Eisenberg David , Sawaya Michael R. , Nelson Rebecca A. , Ivanova Magdalena I. , Sievers Stuart , Wiltzius Jed , Cascio Duilio
Published: June 2021

Protein aggregation diseases, including amyloid and prion diseases, are accompanied by the deposition of elongated, unbranched protein fibrils having similar tinctural and diffraction properties. Our research group has determined atomic structures for some 45 different segments of fibril‐forming proteins which in isolation from the rest of the protein form fibrils and microcrystals, and find that the atomic structures display common characteristics. The segments are selected by a computer algorithm from the sequences of proteins known to form amyloid‐like fibrils, and are then synthesized and crystallized by conventional methods. Because amyloid crystals are invariably smaller than ordinary protein crystals by a factor of 10,000, X‐ray diffraction data from them must be recorded on a microcrystallography synchrotron beam line. The atomic structures may be termed steric zippers, a newly recognized class of protein structures. Steric zippers are formed from the intermeshing of two beta sheets. In each sheet, extended protein strands hydrogen bond to each other up and down the fibril, forming either a parallel or antiparallel sheet. Then two sheets intermesh in one of eight possible ways, to form the steric zipper
Novel neuro‐regulation of peripheral metabolism in aging
Authors: Barzilai Nir
Published: June 2021

Decline in insulin action is a metabolic feature of aging and may be involved in the development of age related diseases including Type 2 Diabetes Mellitus (T2DM) and Alzheimer's disease (AD). A novel mitochondrial peptide, Humanin (HN) has been recently recognized for its neuro‐protective role against AD‐related neurotoxicity, and an IGFBP3 partner. Here we show that, in addition to its neuro‐survival effects, HN regulates both hepatic and peripheral insulin action via the hypothalamus. Infusion of HN ICV significantly improves overall insulin sensitivity, both at the liver and skeletal muscle. The central effects of HN on insulin action are associated with activation of hypothalamic STAT‐3 signaling; effects that are negated by co‐inhibition of hypothalamic STAT‐3. Furthermore, endogenous IGFBP‐3 in the hypothalamus tempers the effects of HN on glucose metabolism. Peripheral infusions of novel HN derivatives reproduce the insulin‐sensitizing effects of central HN. HN represents a novel link between diabetes and neurodegeneration and along with its analogues offers a potential therapeutic tool to improve insulin action and treat T2DM. Importantly, acute regulation of peripheral insulin action is probably elicited in the hypothalamus and the integrity of GH/IGF system is probably needed to ensure normal metabolism with aging. This line of investigation may lead to strategies of blocking IGF‐1 effects in the periphery (reducing risk for cancer), while protecting against other age‐related disease with central origins (T2DM and Alzheimer's).
HIV assembly ‐‐ The macrophage scenario
Authors: Marsh Mark , Pelchen‐Matthews Annegret , Theusner Kristina
Published: June 2021

The assembly of enveloped viruses in eukaryotic cells requires interaction with cellular membrane trafficking and protein sorting machineries. Structural proteins of the virus, and key cellular components, must be brought together in a spatially and temporally controlled manner to allow the formation of infectious virus particles. The human immunodeficiency virus (HIV‐1) is a particularly useful model for analysing these activities. The small genome, and the fact that only three virally encoded proteins are required for infectious particle formation, makes this virus an attractive model for cellular and biochemical analysis.

We have studied the formation of HIV in human macrophages and find that particles assemble on the limiting membrane, and bud into the lumen, of an intracellularly sequestered plasma membrane domain. Viruses appear to be stored within this assembly compartment prior to release. This release may be induced when T cells interact with infected macrophages leading to the formation of so‐called (virological synapses) through which viruses are efficiently transferred to T cells. Characterisation of the assembly compartment will likely shed new light on the molecular basis of HIV assembly and provide insights to the ways in which these viruses exploit the properties of monocyte‐derived cells for efficient cell‐to cell transmission.
γ‐GLUTAMYLTRANSFERASE OF CANCER CELLS AT THE CROSSROADS AMONG TUMOR PROGRESSION, DRUG RESISTANCE AND DRUG TARGETING.
Authors: Pompella Alfonso , Corti Alessandro , Zunino Franco , Paolicchi Aldo
Published: June 2021

γ‐Glutamyltransferase (GGT) is increased human malignancies, with roles in cell redox regulation and tumor progression (Paolicchi et al., Bioch. Pharm. 2002; Pompella et al., Curr. Op. Pharm. 2007). We have observed increased levels of DNA damage in GGT‐overexpressing cells, suppressed by specific GGT inhibitors, iron chelator DFO and lipid antioxidants. GGT is also implicated in drug resistance, as it favours the reconstitution of cellular glutathione. But the enzyme can actually play as a factor in drug sensitivity as well:

i) protection offered by GGT against cisplatin depend on extra‐cellular reactions of cisplatin with GGT‐derived thiol metabolites (Franzini et al., EJC 2006, 42: 2623);

ii) with 4‐[N‐(S‐glutathionyl‐acetyl)amino] phenylarsinous acid (GSAO) ‐ a promising anti‐angiogenic drug ‐ GGT activity acts as a sensitizing factor: GSAO is cleaved by GGT expressing cells, thus producing the active metabolite GCAO (Dilda et al., JBC 2008);

iii) NO‐donor agents (e.g. S‐nitroso‐glutathione, GSNO) have been highlighted as "chemosensitizing agents". GGT selectively metabolizes GSNO (Angeli et al., ABB 2008), thus releasing its NO load: its expression may thus be exploited to target NO to GGT‐expressing tumor cells.

Supported by Istituto Toscano Tumori (ITT, Firenze) and Fondazione Fibrosi Cistica (FFC, Verona) ‐ Italy.
Role of Type II Alveolar Epithelial Cell Transcription Factor FoxM1 in the Repair of Alveolar Epithelial Barrier
Authors: Liu Yuru , Sadikot Ruxana , Zhao You‐yang , Kalinichenko Vladimir , Malik Asrar
Published: June 2021

The repair of the alveolar epithelial barrier is essential for the restoration of normal alveolar gas exchange function and homeostasis after lung injury. The normal alveolar epithelium is composed of two types of cells: flat type I cells comprising ~95% of the gas‐exchange surface, and cuboidal type II cells, which secrete surfactant. Upon alveolar epithelial injury, some or all of the type II cells proliferate and trans‐differentiate into type I cells, thus repairing the epithelial barrier function. However, molecular mechanisms of repair of this crucial barrier are unknown. Here, we utilized a mouse model of lung injury caused by i.t. Pseudomonas aeruginosa (PA) infection. We observed that the expression of FoxM1, a forkhead transcription factor regulating epithelial cell proliferation, was increased 3‐fold specifically in type II cells at 72h post infection, coincident with the cell proliferation phase and preceding the re‐annealing of alveolar epithelial barrier. To investigate the role of FoxM1, we utilized an alveolar type II cell specific FoxM1 knock‐out mouse line. We observed decreased cell proliferation rate and as well as defective alveolar epithelial barrier repair after PA challenge of mice with the mutant background. These findings suggest a critical role of transcription factor FoxM1 in the mechanism of alveolar epithelial barrier repair and mediating the transition from type II to type I cells required for barrier re‐annealing.