bluuebunny/crossref_metadata_2025 huggingface dataset:
The orexin receptor 1 (OX1R) in the rostral medullary raphe contributes to the hypercapnic chemoreflex in wakefulness, during the dark (active) period of the diurnal cycle
Authors: Dias Mirela B , Li Aihua , Nattie Eugene E
Published: June 2021

The orexin system plays an important role in the hypercapnic chemoreflex during wakefulness, and the OX1R in the retrotrapezoid nucleus (RTN), one central chemoreceptor site, participates in this reflex. We hypothesized that OX1Rs at the rostral medullary raphe (rMR) contribute to central chemoreception. In unanesthetized rats, ventilation was recorded in a whole body plethysmograph. We studied the effects on ventilation in air and 7%CO2 of focal antagonism of OX1R in the rMR by microdialysis of SB‐334867 in rats during wakefulness and NREM sleep, separately under dark and light periods. During wakefulness in the dark period, but not in the light period, SB‐334867 caused a 16% reduction of respiratory response to CO2 (167.1 ± 5.6 ml/100g/min) compared with vehicle (195.5 ± 7.2 ml/100g/min) (P< 0.01). There was no significant effect in sleep. The basal ventilation, body temperature and metabolic rate were not affected. No effect was observed in a separate group which had the probes misplaced. In the RTN, the focal antagonism of OX1R caused a 30% attenuation of the CO2 response in wakefulness, a greater effect than that observed in this study. However, the putative chemosensitive cells in the raphe may be distributed over a wider region than those in the RTN. We conclude that OX1Rs in the rostral medullary raphe contribute to the hypercapnic chemoreflex in wakefulness, during the dark period in rats. (HL 28066)
Functional proteomic studies to identify Oct4A possible interactors.
Authors: Spelat Renza , Ferro Federico , Daria Anna , Tonon Federica , De Pol Ilaria , Fontanini Alessandra , Impiombato Francesco Saverio Ambesi , Curcio Francesco
Published: June 2021

Oct‐4A (Octamer binding protein 4, isoform A) is a key component of the molecular circuitry which regulates stem cells self‐renewal and pluripotency. Very little is known about the mechanisms through which Oct‐4A responds to complex extracellular stimuli and regulates stemness. In our studies we noted that Oct‐4 was expressed both in nucleus and cytoplasm, implicating the presence of nuclear‐cytoplamatic translocation mechanisms. To further explore the functional network of Oct‐4A, in vitro and in vivo methods were used to search interacting proteins in human Dental Pulp Marrow Similar Cells (DPMSC) and NTera2, a human embryonal carcinoma (EC) stem cell line that shares many characteristics with human embryonic stem cells. Glutathione S‐transferase pull‐down and co‐immunoprecipitation assays identified Erk1/2 as a possible Oct‐4A interactor. One mechanism by which Erk1/2 kinases ensure their specificity of action is by interacting with their substrates through docking domains, enhancing also the efficiency of phosphorylation. Oct‐4A sequence analysis evidenced the presence of a D‐domain supporting our interaction hypothesis. Further studies are needed to better understand the mechanism.
Maternal obesity affects MicroRNA expression in fetal muscle at mid‐gestation
Authors: Yan Xu , Zhu Mei J , Dey Arup , Ford Stephen P , Nathanielsz Peter W , Du Min
Published: June 2021

INTRODUCTION

Obesity is increasing at an alarming rate. Previous findings in our laboratory have shown that maternal obesity leads to increased adipogenesis in fetal muscle. Expression of adipogenic genes lead to adipogenesis. MicroRNAs play a crucial role in the regulation of gene expression. Using the pregnant sheep as a model, the objective was to assess microRNA expression in fetal muscle due to maternal obesity.

METHODS

Non pregnant ewes were randomly assigned to a control (Con, 100% of NRC recommendations, n = 5) or obesogenic (OB, 150% of NRC, n = 5) diet from 60 days before to 75 days after conception, when fetal longissimus dorsi (Ld) muscle was collected. MicroRNAs were extracted, purified and subjected to microRNA microarray analyses using the known microRNAs from human, rat, mouse and cattle.

RESULTS

67 microRNAs were identified in fetal LD muscle based on the generation of strong hybridization signals. Among those, 3 microRNAs, including hsa‐miR‐381, hsa‐let‐7g and bta‐miR‐376d, were differentially expressed between the Con and OB groups, which was confirmed by real‐time quantitative PCR. Hsa‐miR‐381 was 51.7 ± 17.3% higher (P < 0.05) in the OB fetal muscle compared to Con, while Hsa‐let‐7g (21.5 ± 4.9% (P = 0.06) and Bta‐miR‐376d (26.0 ± 8.8% (P < 0.05) were lower.

CONCLUSION

Maternal obesity induced differential expression of microRNAs in fetal LD muscle. Since microRNAs regulate gene expression, changes in microRNA expression potentially play important roles in the development of fetal muscle, including adipogenesis, in the setting of maternal obesity. (Supported by NIH 1R03HD057506 and Wyoming INBRE P20RR016474)
Macrophage hemoglobin scavenger receptor CD163 is functionally linked to heme oxygenase‐1 and ferritin expression in human diabetic atherosclerotic plaques
Authors: Purushothaman Meerarani , Purushothaman K‐Raman , Levy Andrew P , Lento Patrick A , Fallon John T , Fuster Valentin , Sharma Samin K , Moreno Pedro R
Published: June 2021

Background

The macrophage hemoglobin scavenging receptor CD163 plays a major role in the clearance of hemoglobin (Hb) released from lysed red blood cells after intraplaque hemorrhage (IPH). We hypothesize that impairment in CD163 expression may alter HO‐1 and ferritin defense mechanism in the clearance of Hb in diabetic (DM) plaques inducing atherothrombosis.

Methods

Human DM atherosclerotic plaques (33) and no‐DM plaques (49) were characterized using H&E. The macrophage (CD68) and CD163 protein expressions were quantified by double label immunochemistry and gene expression in serial sections by real time PCR. The HO‐1 and ferritin protein expression was graded by immunohistochemistry.

Results

The mean percentage of macrophages expressing CD163 was significantly decreased in DM plaques (DM 26.2 % ± 2 vs No‐DM 66.9 % ± 2, p=0.0001). The CD163 and HO‐1 mRNA expressions were down regulated in DM (DM 0.0689±0.017 vs No‐DM 0.3078±0.055, p=0.002, and DM 0.002±0.0006 vs No‐DM 0.0369±0.012, P=0.005) respectively. The protein expression of ferritin was also decreased in DM plaques (DM 0.7±0.1 vs no‐DM 2.6±0.2, p=0.0001).

Conclusion

CD163 may have a functional role in the induction of HO‐1 and ferritin expression. Thus, impairment in CD163 expression may alter HO‐1 and ferritin defense mechanism leading to atherothrombosis in DM plaques.
Oxidized Low Density Lipoprotein Induced Endothelial Cell Apoptosis via Survivin Down‐Regulation
Authors: Li Rongsong , Beebe Tyler , Cui Jeffery , Majumdar Rohit , Takabe Wakako , Hsiai Tzung
Published: June 2021

In response to oxidized low density lipoprotein (Ox‐LDL), vascular cells undergo apoptosis. Survivin, a Wnt target gene and a member in the inhibitor of apoptosis protein (IAP) family, is implicated in cytokinesis, cancer development and regulation of apoptosis. In advanced atherosclerotic lesions, Survivin expression was almost absent despite an increase in X‐linked inhibitor of apoptosis protein (XIAP) and cellular inhibitor of apoptosis protein 2 (cIAP2) expression. In this study, we examined whether Survivin played a role in Ox‐LDL‐ induced endothelial cell apoptosis. Treatment of human aortic endothelial cells (HAEC) with Ox‐LDL for 24 hour significantly down‐regulated both Survivin mRNA and protein expression. While Ox‐LDL increased the expression of transcription factor KLF4, silencing KLF4 with siRNA partially but significantly attenuated Ox‐LDL‐mediated Survivin reduction. Over‐expression of Survivin with recombinant Survivin adenovirus inhibited Ox‐LDL‐induced apoptosis. Thus, our data suggest that Survivin is implicated in Ox‐LDL‐mediated endothelial cell apoptosis, and KLF4 may regulate Survivin expression.
Early post‐myocardial infarction survival in MRL mice is mediated by attenuated apoptosis and inflammation but depends on genetic background
Authors: Hunt Darlene , Campbell Patrick , Zambon Alexander , Vranizan Karen , Evans Sylvia , Kuo Hai‐Chien , Yamaguchi Ken , Omens Jeffrey , McCulloch Andrew
Published: June 2021

The Murphy Roth Large (MRL) mouse, a strain capable of regenerating right ventricular myocardium, has a high post‐ myocardial infarction (MI) survival rate compared with C57BL/6J (C57) mice. The biological processes responsible for this advantage are unknown. To assess the effect of genetic background, the LG/J strain, which provides 75% of the MRL composite genome, was included in the study. The MRL survival advantage versus C57 mice (P = 0.01) occurred largely in the first 5 days; LG/J survival was intermediate (P = NS). Analysis and annotation of microarray data revealed significantly attenuated acute apoptotis (P < 0.05) and delayed expression of stress response transcripts in MRL hearts compared to C57 hearts. Supporting the microarray results, there were fewer TUNEL‐positive cells 1 day post‐MI (P < 0.05) and fewer CD45‐positive inflammatory cells in MRL hearts 2 days post‐MI (P < 0.01) compared to the C57. Chronically, MRL hearts had smaller infarct scars and attenuated ventricular dilation 30 days post‐MI than C57 hearts (P < 0.05). We conclude that the early post‐MI survival advantage of MRL mice over the C57 strain is mediated at least in part by reductions in apoptosis and inflammatory infiltration, and that this may influence chronic remodeling. The intermediate survival rate of LG/J mice suggests the high tolerance for MI in the MRL could be derived from its shared genetic background with the LG/J. Support: NIH
α‐Retinol acts as a chemical tracer for the RBP4‐independent distrubution of vitamin A in lactating sows
Authors: Dever Joseph T , Surles Rebecca L , Davis Christopher R , Tanumihardjo Sherry A
Published: June 2021

α‐Retinol (αR) is a structural analog of retinol that does not bind to serum retinol‐binding protein (RBP4). In this study, α‐retinyl acetate (αRA) was synthesized and given orally (35 μmol) to vitamin A (VA)‐deficient lactating sows (n = 11) as a tracer for RBP4‐independent retinol transport and tissue uptake. Serum αR concentrations peaked at 2 h (70 ± 23 nmol/L, mean ± SEM) primarily as four distinct α‐retinyl esters. Peak αR milk concentrations were detected at 7.5 h (371 ± 83 nmol/L). Sow livers collected 25 d post‐dose contained a high percentage of the αR dose (52 ± 15%, mean ± SD) likely due to the inability of RBP4 to transport αR from the liver. Nursing piglets (n = 17) killed 3 days after the αRA‐dosing of sows (n = 5) had 2.2 ± 0.7% of the αRA dose in their livers, which correlated to an estimated 15–26% transfer of the αRA dose from individual sows to their litters. Total liver retinol levels for all sows and piglets were <0.1 μmol/g liver confirming their VA‐deficient status. RBP4‐independent mechanisms play a significant role in the uptake of retinol into milk when single, large doses of retinyl acetate are given to VA‐deficient lactating women in developing nations. αR has great potential as a tracer for RBP4‐independent retinoid bioprocesses. Supported by USDA‐NRI 2007‐35200‐17729.
Transcription factor MafB is a mediator of retinoic acid‐induced monocytic cell differentiation
Authors: Zhang Yao , Chen Qiuyan , Ross A. Catharine
Published: June 2021

All‐trans‐retinoic acid (RA), the major active metabolite of vitamin A, regulates monocytic cell cycle and differentiation. We asked whether MafB, a factor involved in development and hematopoiesis, is a mediator of RA‐induced differentiation in THP‐1 human monocytic cells. MafB mRNA and protein levels were up‐regulated by RA dose‐ and time‐dependently. RA and TNFα synergistically regulated MafB expression, mainly at the transcriptional level. MafB protein was highly phosphorylated. Blocking the ERK and p38 pathways reduced phospho‐MafB protein without changing mRNA levels. Next, MafB target genes were screened. SPOCK1, CCL2 and Blimp1 were identified as potential targets, due to the presence of Maf recognition elements in their putative promoter regions. These genes are related to cell communication and differentiation. By RT‐PCR analysis, the regulation of SPOCK1, Blimp1 and CCL2 mRNA levels were highly correlated with MafB mRNA. Decreased expression of SPOCK1, Blimp1 and CCL2 was observed when MafB phosphorylation was blocked. Chromatin immunoprecipitation assays showed increased MafB protein binding to the elements on the promoter regions of SPOCK1, Blimp1 and CCL2 in cells treated with RA and TNFα. We conclude that RA and TNFα‐induced MafB may play a role in monocytic cell differentiation through transcriptional regulation of SPOCK1, CCL2 and Blimp1. Support: NIH DK41479.

Grant Funding Source: NIH DK41479
Dietary Vitamin A Supplementation Alters Brain Metabolism and Networks Interactions in Mice
Authors: Lane Michelle A , Riha Penny , Shumake Jason
Published: June 2021

13‐Cis‐retinoic acid increases depression‐related behavior and disrupts functional connectivity between the raphe nuclei and hippocampus in mice. Hypervitaminosis A also induces psychosis. The current objective was to determine if dietary vitamin A supplementation alters brain metabolism and neuroanatomical networks. Female nude mice consumed either control (2,400 IU vitamin A/kg diet) or vitamin A‐supplemented (12,000 IU vitamin A/kg diet) diets ad libitum for 5 weeks prior to sacrifice. Cytochome oxidase (CO) histochemistry determined neuronal metabolism. Vitamin A supplementation decreased CO activity in the interpeduncular nucleus and subiculum. Covariant analysis of interregional correlations revealed that vitamin A supplementation caused a functional uncoupling between the ventral tegmental area and lateral habenula and the lateral septal nucleus and infralimbic cortex. Path analysis showed that a network consisting of the interpeduncular nucleus, medial and lateral habenuli and ventral tegmental area was effectively uncoupled in vitamin A‐supplemented mice. These data indicate that excess vitamin A consumption alters brain metabolism and networks. Sponsor: RoAccutane Research Group.
OAT1 Knock‐out Mice Define Its Role in Tenofovir Transport and Renal Proximal Tubular Mitochondrial Toxicity
Authors: Kohler James J , Hosseini Seyed H , Green Elgin , Russ Rodney , Santoianni Robert , Lewis William
Published: June 2021

Tenofovir disoproxil fumarate (TDF) is an analog of adenosine monophosphate that inhibits HIV reverse transcriptase. Despite its therapeutic success, renal side effects exist. The role of organic anion transporter 1 (OAT1) in secretion of TDF was determined using OAT1 knock‐out (KO) and wild‐type (WT) with or without TDF (5 week dose). Laser‐capture microdissection (LCM) isolated renal proximal tubules from kidney samples for molecular analyses. Mitochondrial DNA (mtDNA) abundance and ultrastructural pathology were analyzed. mtDNA abundance in KO and WT whole‐kidneys were unchanged regardless of treatment. Renal proximal tubules from KOs also exhibited no change following TDF treatment compared to previous findings in HIV transgenic mice (TG) which exhibited decreased mtDNA abundance. Renal proximal tubules from TDF treated WTs, but not KOs, exhibited increased numbers of irregularly shaped mitochondria with sparse, fragmented cristae. OAT1 has a direct role in transport of TDF in the murine proximal tubules. These data help explain mechanisms of human TDF renal toxicity.
Simultaneous presence of Ins2C96Y mutation uncovers the insulin resistance phenotype in the adipose tissue of PPARγP465L female mice
Authors: Pendse Avani , Tsai Yau‐Sheng , Maeda Nobuyo
Published: June 2021

Mutations in Peroxisome Proliferator Activated Receptor‐γ (PPARγ) affect adipose tissue and insulin sensitivity. The heterozygous PPARγP467L (L/+) mutation was originally identified in insulin resistant patients. Yet, L/+ mice have normal plasma glucose and insulin sensitivity. They have mild hyperinsulinemia and increased pancreatic islet mass, especially on high‐fat diet. We hypothesized that L/+ mutation leads to insulin resistance; however the hyperinsulinemia in mice compensates for it to retain normal plasma glucose. Thus, we introduced Ins2C96Y (akita, A/+) mutation, which reduces plasma insulin, in L/+ mice. Unlike +/+;A/+ littermates, male L/+;A/+ mice have dramatically reduced life span. When compared with +/+;A/+ mice, female L/+;A/+ mice have significant hyperglycemia, smaller pancreatic islets, reduced plasma insulin levels and upregulated gluconeogenesis. In an Insulin Tolerance Test, female L/+;A/+ mice have a smaller reduction in plasma glucose indicating impaired sensitivity to insulin. Adipose tissue explants from L/+;A/+ mice have impaired glucose uptake in response to exogenous insulin. Thus, insulin resistance phenotype can indeed be attributable to L/+ mutation. Our data also provides an excellent mouse model to study diabetes in the context of gender specific physiology.
The Complement Split Products C3a and C5a are potent Activators of Mesenchymal Stem Cells
Authors: Schraufstatter Ingrid , Discipio Richard , Khaldoyanidi Sophia
Published: June 2021

It is known that mesenchymal stem cells (MSC) are recruited to sites of tissue injury to fulfill their repair function. It is also known that there is complement activation, wherever there is tissue injury. We therefore determined the effect of the complement split products C3a and C5a on MSC. FACS analysis indicated that human bone marrow‐derived MSCs express cell‐surface C3a receptors (C3aR) and C5a receptors (C5aR). Both C3a and C5a induced chemotaxis of MSCs in a dose dependent fashion. Specific C3aR and C5aR inhibitors blocked the chemotactic response as did pertussis toxin, indicating that the response was mediated by the known anaphylatoxin receptors in a Gi activation‐dependent fashion.

While C5a causes prolonged activation of many cell types, the response to C3a is generally transient and weak. However, in MSCs both C3a and C5a caused prolonged ERK1/2 and Akt phosphorylation. Phospho‐Akt and phospho‐ERK1/2 were translocated to the nucleus with both stimuli, which was associated with subsequent phosphorylation of the transcription factor Elk. More surprisingly, the C3aR itself was translocated to the nucleus in C3a‐stimulated MSCs. Since nuclear translocation of G‐protein coupled receptors has been shown to induce long‐term effects including transcriptional activation, this novel observation implies that C3a exerts far reaching consequences on MSC biology. The prolonged activation of C3aRs and to a lesser degree of C5aRs was associated with increased expression of several angiogenic factors in MSC including VEGF, bFGF and IL‐8. These results suggest that C3a and C5a present in injured tissues contribute to the recruitment of MSC and that means of activating the C3aR or C5aR on MSC could improve their ischemic repair potential, which would be more attractive for C3a, which lacks the inflammatory action of C5a.
Ethical and legal issues in BTB (Brain/tissue/Bio) Banking
Authors: Ravid Rivka
Published: June 2021

BTB (Brain/Tissue/Bio) Banks form essential repositories for clinical and basic research; The collection, storage, distribution and use of biological materials in research raise many legal and ethical issues which are currently not well regulated on an international level due to differences and conflicting laws and policies.

Brain/Tissue/Bio Banks currently aim at the following objectives:

Foster research in clinical and basic science and serve as a dynamic system with ongoing consultations on the many various daily issues of banking.

Achieve standardization between banks of commonly accepted criteria for the pathological diagnosis and compatibility of protocols (SOP's) for tissue procurement, management and preparation.

Facilitate multi‐center concordance studies and studies of risk factors in diseases which have genetic end environmental components.

Monitor safety measures and secure storage.

Abide by ethical and legal codes of conduct; the laws regulating consent and autopsy procedures and the ethical guidelines are significantly different in the various repositories.

To create and develop the adequate infrastructure for these activities, we are in the process of publishing an inventory of the medico‐legal and ethical framework conform local legislation. We have also made an inventory of the ethical aspects applied in daily practice of procurement, management, dissemination, confidentiality, “Financial gain” and genetic testing.

These results of the inventarisation are now being incorporated into the 3rd edition of ISBER's “Ethical Issues of Human Subjects and Animals”.
Low‐Dose Chronic Estrogen Exposure Causes Follicular Pathology and Alterations in Mullerian Inhibiting Substance Expression in the Rat Ovary
Authors: Gilbreath Ebony Turner , Agnew Dalen , MohanKumar Sheba , MohanKumar Puliyur
Published: June 2021

Our previous findings indicate that chronic exposure to a low dose of estradiol‐17β (E2) suppresses the hypothalamo‐pituitary‐gonadal axis, but increases serum estrogen levels. In the present study we studied ovarian morphology after E2 exposure to determine if there was any evidence of polycystic ovarian syndrome (PCOS). We hypothesized that chronic E2 exposure would increase the expression of Mullerian inhibiting substance (MIS) as in PCOS. Adult female rats were sham‐implanted or implanted with slow‐release E2 pellets (20ng/day) for 30 (E30 group), 60 (E60 group), or 90 (E90 group) days. Old constant estrous (OCE) rats were used for comparison. Ovaries were collected on the day of estrus and subjected to histological examination. Follicular size increased with the duration of E2 exposure with the E90 and OCE groups having the largest Graafian follicles. There was a marked reduction in fresh corpora lutea (CL), (mean±SE; um) in the E30 group (0.2±0.2) and a complete absence in other groups compared to control (7±3.1) suggesting failure of ovulation. Moreover, there was a significant reduction in old CLs in the E90 group (1.67±1.5) compared to control (6±1.6) suggesting that this was a chronic condition. E2 treatment decreased MIS immunolabeling in follicles indicating a possible initial facilitation of follicular recruitment followed by degeneration in the absence of ovulation. Ovarian morpohology in OCE rats was comparable to the E2 treated groups suggesting that E2 treatment causes ovarian aging.
Cellular localization of connectiv tissue growth factor in panceatic fibrosis in mice
Authors: Jiang Yuying , Brigstock David R
Published: June 2021

Connective tissue growth factor (CTGF) is a pro‐fibrogenic molecule that is implicated in the pathogenesis of pancreatic fibrosis. In this study, immunohistochemistry was used to determine the cellular localization of CTGF in the pancreata of C57/BL6 mice in which chronic pancreatitis was induced by 50 μg/kg cerulein i.p. given 6 times a day, 3 days/wk for 4 wks. Pancreatic fibrosis was confirmed by the presence of interstitial collagen deposition as detected by Sirius Red staining and by the presence of activated (α‐SMA‐positive) pancreatic stellate cells (PSC). Compared to control mice, real time PCR of diseased pancreatic tissue showed significant up‐regulation of mRNA for key fibrogenic markers including collagens I, III and VI, MMP‐2, TIMPs ‐1 and ‐2, TGF‐β1 and CTGF. CTGF was localized by incubation of pancreatic sections with rabbit or chicken anti‐CTGF antibodies and immunoreactivity was detected by peroxidase staining using light microscopy or immunofluorescence using confocal microscopy. CTGF was detected primarily in acinar cells and duct‐like cells with weaker production by presumptive activated PSC. A high proportion of CTGF producing cells were also positive for PCNA. CTGF production is thus a feature of multiple actively proliferating cell types in the fibrotic pancreas supporting a role for CTGF in tissue remodeling, matrix production, and cell survival after injury.
Simvastatin ameliorates renal fibrosis via suppressing uterine sensitization‐associated gene‐1 (USAG‐1), a BMP‐7 antagonist, in mouse adenine‐induced tubulointerstitial injury model
Authors: Hamasaki Yoshifumi , Okamoto Koji , Doi Kent , Fujita Toshiro , Noiri Eisei
Published: June 2021

Background & Purpose

It is known that BMP‐7 counteracts with TGF‐β, the dominant molecule promoting renal fibrosis, and that uterine sensitization‐associated gene‐1(USAG‐1), the dominant BMP‐7 antagonist expressing in distal tubular epithelial cells, promotes renal fibrosis. In this study, we investigated whether simvastatin (SIM), one of the HMG‐CoA reductase inhibitors, attenuates renal fibrosis by modulating BMP‐7 and USAG‐1 mediated pathway.

Method & Results

C57/BL6 mice fed by 0.2% adenine‐containing diet for 4 weeks showed significant increase of blood urea nitrogen (BUN) accompanied with severe tubulointerstitial fibrosis. SIM treatment for two weeks (50mg/kg/day) significantly reduced BUN compared with the control group (p<0.01). In pathological analysis, the area of fibrosis and the expression of alpha smooth muscle actin were significantly attenuated by SIM (p<0.05). In quantitative real‐time PCR, USGA‐1 expression was significantly lower in the SIM group (p<0.05). MDCK cells (distal epithelial tubular cells) incubated with TGF‐β (5ng/ml) for 72 hours showed increased expression of USAG‐1. SIM significantly reduced USAG‐1 expression (p<0.01). Several database analyses predicted the binding sites of HOXA‐13, a transcriptional factor, in the promoter region of USAG‐1 gene. The expression assay in vitro suggested that HOXA13 functions as a suppressor of the USAG‐1 gene and SIM decreased USAG‐1 expression by enhancing HOXA13.

Conclusion

Our data showed that SIM ameliorated renal fibrosis by suppressing USAG‐1. Decreased USAG‐1 levels may enhance the counteract effect of BMP‐7 against TGF‐β. We also demonstrated that HOXA13 plays a crucial role in the mechanism of this action by SIM.
Abnormality of capillarity and oxidative enzyme activity in slow muscle of type 2 diabetic rats
Authors: Murakami Shinichiro , Fujino Hidemi , Kondo Hiroyo , Takeda Isao , Momota Ryusuke , Kumagishi Kanae , Ohtsuka Aiji
Published: June 2021

Type 2 diabetes mellitus is tightly linked to impaired skeletal muscle glucose uptake and storage. The 3‐D capillarity, the myosin heavy chain isoforms (MyHC) transformation and succinate dehydrogenase (SDH) activity in the soleus muscle were determined between Goto‐Kakizaki (GK) rats, a spontaneous, non‐obese type 2 diabetes model and age matched Wistar rats (Con)(9 months old). The volume, diameter and tortuosity of the capillary in soleus muscle of GK were significantly lower than those of Con. Thus, the morphological microvascular alterations in the soleus muscle were observed in diabetes rats. Although the soleus muscle of Con was composed of both type I and type IIa MyHCs, all the muscle fibers of the GK were type I MyHC. Furthermore, the SDH activity of type I MyHC fiber in GK decreased significantly compared with that of Con. These results indicate that microvascular alterations and changes in the MyHC of skeletal muscles in diabetic rats may be due to impairment in glucose metabolism. This study was supported by Grants‐in‐Aid for Scientific Research (19300196 and 21700559) from the Japanese Ministry of Education, Culture, Sports, Science and Technology.
CYP1B1 and Endothelial Nitric Oxide Synthase Combine to Sustain Proangiogenic Functions of Endothelial Cells under Hyperoxic Stress
Authors: Sheibani Nader , Tang Yixin , Sorenson Christine M
Published: June 2021

Lack of CYP1B1 expression is associated with attenuation of retinal endothelial cell (EC) capillary morphogenesis in vitro and angiogenesis in vivo. This is largely attributed to increased intracellular oxidative stress and increased production of thrombospondin‐2 (TSP2), an endogenous inhibitor of angiogenesis. Here we demonstrate that endothelium nitric oxide synthase (eNOS) expression is dramatically decreased in the EC prepared from retina, lung, heart, and aorta of CYP1B1‐deficient (CYP1B1−/−) mice compared to wild type (CYP1B1+/+) mice. The eNOS expression was also decreased in retinal vasculature of CYP1B1−/− mice. Inhibition of eNOS activity in cultured CYP1B1+/+ retinal EC blocked capillary morphogenesis concomitant with increased oxidative stress and reduced NO bioavailability. Furthermore, expression of a constitutively active eNOS in CYP1B1−/− retinal EC or their incubation with a NO donor reduced oxidative stress and improved cell migration and capillary morphogenesis. In addition, acute inhibition of CYP1B1 activity in the CYP1B1+/+ retinal EC resulted in increased oxidative stress, reduced NO bioavailability, and attenuation of capillary morphogenesis. Together our results suggest CYP1B1 constitutive expression produces long term effects on EC that favors eNOS expression and NO bioavailability by reducing oxidative stress and TSP2 expression. Supported by EY018179 and DK067120
Thyroid hormone receptor‐beta promotes angiogenesis stimulating ERK phosphorylation
Authors: Suarez Jorge , Chavira Citlalic , Fricovsky Eduardo , Wang Hong , Suarez‐Ramirez Jorge Adolfo , Dillmann Wolfgang H.
Published: June 2021

Deficient angiogenesis is one of the causes leading to tissue ischemia and dysfunction. Thyroid hormones have been known to possess angiogenic properties; however, the detailed mechanisms involved in this effect are unknown. The activation of the extracellular signal‐regulated kinase (ERK) by phosphorylation in the mitogen‐activated protein kinase (MAPK) pathway is known to directly link growth factor signaling and cell migration and proliferation. We hypothesized that the angiogenic effect of thyroid hormones is mediated by a specific thyroid hormone receptor (TR) linked to the activation of ERK in endothelial cells. We analyzed ERK phosphorylation in cultured rat aortic endothelial cells by Western blot after exposure to thyroid hormone (T3) or adenoviral expression of either TRα or TRβ. In addition, we investigated the effect of these treatments on aortic sprouting. Our results showed that T3 increased ERK phosphorylation in a dose response manner. Only TRβ induced ERK phosphorylation. Aortic sprouting was increased by T3 and TRβ expression. In conclusion, the angiogenic effect of thyroid hormone is mediated by specific activation of TRβ through activation of the MAPK pathway.
Targeted VEGF Therapy Favorably Alters Collagen Deposition and Quality after Myocardial Infarction
Authors: Cheheltani Rabee , Rosano Jenna M , Wang Bin , Pleshko Nancy , Kiani Mohammad F
Published: June 2021

Every year 1.5 million people in the United States alone suffer from myocardial infarction (MI). MI may cause adverse cardiac remodeling, leading to congestive heart failure. Previously, we have shown that a low dose of vascular endothelial growth factor (VEGF) targeted via anti‐P‐selectin immunoliposomes to the infarcted heart improves cardiac function and vascular perfusion. The aim of this study is to examine the role of targeted VEGF in cardiac remodeling after MI. An MI was induced in rats, and treated with anti‐P‐selectin conjugated immunoliposomes containing VEGF (0.12 ug/kg), or left untreated. After four weeks, hearts were excised and stained with Gomori's trichrome and Picrosirius red for collagen. Fourier transform infrared imaging spectroscopy (FT‐IRIS) data was obtained from sections of the left ventricular wall to assess molecular changes. In hearts treated with targeted VEGF therapy, collagen deposition was reduced as evidenced by collagen volume fraction in the anterior wall (50.0 ± 4.5 % vs. 86.7 ± 5.9 %, untreated), and the percentage of circumference that is scar tissue (23.9 ± 5.9 % vs. 39.2 ±1.8 %). The FT‐IRIS data demonstrated that the ratio of mature to immature crosslinks was greater in the treated tissue. Together, these data show that targeted VEGF therapy modifies both collagen quality and quantity, suggesting that it favorably alters cardiac remodeling. Supported by a grant from the AHA.
The possibility of prevention in orthostatic hypotension by water drink
Authors: Abe Chikara , Tanaka Kunihiko , Morita Hironobu
Published: June 2021

It is well known that the baroreflex has a significant role in arterial pressure (AP) maintaining during postural change. It is assumed that the AP would decrease during rear up postural change in sinoaortic‐denervated rat, and indeed the AP decreased by 15 ± 1 mmHg during simple rear up in the present study. However, the different AP response was observed in the rear up for water drink: i.e., the AP was increased by 55 ± 7 mmHg. The AP increased and reached to the plateau level during water drink, and then immediately decreased when the rat stopped drinking. This pressor response was not affected by height of water bottle and osmolality of solution. Furthermore, this pressor response was completely abolished by prazosin, and water infusion via the gastric tube did not increase the AP, suggesting that efferent fiber is sympathetic nerve and the afferent receptor might exist in the area from the oral to esophagus. From the present study, it is possible that the orthostatic hypotension can be prevented by water drink.
T‐ and L‐type Calcium Channels Contribute to Myogenic Tone In Cerebral Arteries
Authors: El‐Rahman Rasha Abd , Turner Raymond , Welsh Donald
Published: June 2021

The study scrutinized which voltage‐operated Ca2+ channels are expressed in cerebral arterial smooth muscle cells, and what role they play in myogenic tone development. A broad RT‐PCR screen of α1 subunits revealed mRNA expression of L‐type (Cav1.2) and T‐type (Cav3.1, and Cav3.2) Ca2+ channels in cerebral arterial smooth muscle cells. Western blot analysis conducted on whole arteries subsequently showed that all 3 α1 subunits were present at the protein level with T‐type expression qualitatively greater than L‐type. An immunohistochemical analysis of whole arteries revealed that Cav1.2 was primarily expressed in perivascular nerves although some limited/punctuate labeling was observable in smooth muscle. In contrast, the T‐type (Cav3.1, and Cav3.2) channels were robustly expressed in cerebral arterial smooth muscle and display defined periodicity. Functional measurements performed on cerebral arteries pressurized to 80 mmHg revealed that L‐type Ca2+ channels blockers, such as nifidipine (50–300nM) partially attenuate myogenic tone although a near complete blockade was achievable with the further addition of Mibefradil (300nm–1μM), a T‐type Ca2+ channel blocker. Cumulatively, these findings indicate that both L‐ and T‐type Ca2+ channels are expressed in cerebral arterial smooth muscle cells and that both Ca2+ channels play an important role in establishing myogenic tone in small cerebral arteries. These findings have important conceptual and therapeutic implications particularly as it relates to the treatment of cerebrovascular diseases. Supported by CIHR.
Effect of the Valsalva maneuver on cardiac‐coronary interaction studied by coronary wave intensity in humans
Authors: Rolandi Cristina , Nolte Froukje , Remmelink Maurice , Baan Jan , Piek Jan , Spaan Jos A.E. , Siebes Maria
Published: June 2021

Coronary wave intensity (WI) reflects the effects of cardiac contraction and relaxation on coronary blood flow dynamics. The typical coronary WI pattern shows backward and forward compression waves in early systole (BCW and FCW, resp.), followed by forward and backward expansion waves (FEW and BEW, resp.) during early relaxation. The severe cardiovascular stress imposed by a Valsalva maneuver (VM) was studied in relation to coronary WI.

In 8 patients undergoing cardiac catheterization, we simultaneously recorded left ventricular (LV) and aortic pressure (Pa), and intracoronary pressure (Pd) and flow velocity (v), while the patients performed a VM. WI was computed as WI = (dPd/dt)·(dv/dt). Changes in the peaks of the dominant waves were compared to changes in pulse pressure (PPa) and LV contractility (LVdPdt).

During the strain phase of the VM, forward WI was reduced by almost 80% (p < 0.015). The intensity of the BEW dropped to less than half of the BCW (p < 0.02). PPa was highly correlated to the FCW and FEW (r = 0.94, p < 0.006) and LVdPdt was the major determinant of the BEW (r = 0.97, p < 0.001).

We conclude that the VM strongly attenuated cardiac‐coronary interaction. Reduced LV filling and contractility during the strain decreased the energy transmission from the heart to the coronary waves. The resulting decline in the early systolic FCW and early diastolic BEW served to impede coronary inflow.

(Support: NHF grant 2006B186)
Mammalian differences in baroreflex control of coronary conductance
Authors: Quail Anthony , Hamut Mutalip , Seah Peng , McLeod Damian , Cottee David , White Saxon
Published: June 2021

Integrated autonomic control of the coronary circulation is inconsistent with respect to vagal cholinoceptor activity. Baroreflex control of regional coronary conductance was investigated in chronically prepared awake sheep, and compared to our dog data. Pulsed Doppler flow probes were implanted on the right (R), circumflex (Cx) and anterior descending (AD) coronary arteries. Aortic (Pa) and central venous pressure catheters were placed via the superficial cervical vessels. Baroreflex responses were evoked by elevating upper‐body Pa using an external aortic occluder at a controlled (atrioventricular pacing) heart rate (HR) of 150 and 180 min−1. Pacing the heart upward raised baroreflex and metabolic activity and evoked a differential rise in coronary conductance where Cx was greatest followed by R then AD. Block of cholinoceptors (ch), β‐adrenoceptors (β), alone and together (ch‐β), then with α‐adrenoceptors (α) block, at different HR, revealed that in all 3 beds an underlying ch constrictor effect was balanced by the summed dilator effects of β, plus a probable α‐enhanced, vagal interaction mechanism. The net effects summate to enhance conductance in Cx, but balance in R and AD. Therefore, differences exist between species for baroreflex evoked cholinoceptor effects in the mammalian coronary circulation. These are constrictor in sheep, and dilator in the dog. Funding: Hunter Medical Research Institute
The Effect of Nut Consumption on Fasting Plasma Glucose Levels in Pre‐Diabetic and Diabetic Adults
Authors: Torabian‐Riasati Setareh , Assadi Mahnoosh , Plunkett Scott
Published: June 2021

The present study aimed to examine the effects of nut consumption on fasting blood glucose (FBG) levels among type 2 diabetic and pre‐diabetic subjects. Twenty‐seven diabetic (fasting blood glucose >125 mg/dl) and pre‐diabetic (fasting blood glucose 100–125 mg/dl) subjects between the ages of 33–86 years old were recruited. The study used an 8‐week randomized (3×3) cross‐over design with 1‐week washout period between treatments (walnut, almond, and control). The study results showed no significant difference in FBG levels in diabetic and pre‐diabetic subjects on a nut‐containing diet compared to habitual diet (control) with p = .727 for almond and p =.791 for walnut. Combining both nut groups also showed no significant difference in FBG levels when compared to control (p = .963). When diabetic subjects were compared to pre‐diabetic subjects, both receiving nut‐containing diet, there was no significant difference in FBG between groups (p =.422). In conclusion, our study found no significant effect on FBG levels among diabetic and pre‐diabetic subjects while on a nut‐containing diet compared to habitual diet. Nevertheless, the beneficial effects of nut ingestion due to its desirable lipid profile and high level of antioxidant content in the context of primary prevention of cardiovascular disease can not be ignored.
DYSLIPIDEMIA AND PERIPHERAL PREDIABETIC NEUROPATHY
Authors: Maksimchyk Yury , Watcho Pierre , Lupachyk Sergey , Obrosova Irina G
Published: June 2021

Evidence for the presence of diabetes‐like neuropathy at prediabetic stage, prior to development of hyperglycemia, is emerging from both experimental and clinical studies. Until now, it has not been sorted out whether prediabetic neuropathy (PN) results from glucose intolerance, or other factors such as impaired insulin signaling, hypertriglyceridemia, hypercholesterolemia, and/or increased NEFA. We evaluated relative roles of the aforementioned factors in prediabetic neuropathy. Experiments were performed in Zucker lean and Zucker fa/fa rats, a model of prediabetes and obesity. 16 wk‐old Zucker fa/fa rats with obesity, glucose intolerance, hyperinsulinemia, hypertriglyceridemia, hypercholesterolemia, and increased serum NEFA levels, displayed sensory nerve conduction velocity (SNCV) deficit, thermal and mechanical hypoalgesia, and tactile allodynia. A 4‐wk treatment with the niacin derivative acipimox reduced serum insulin, NEFA, and triglyceride without affecting impaired glucose tolerance and total and VLDL‐LDL cholesterol levels. It also reversed SNCV deficit and alleviated small sensory fiber neuropathy. These findings suggest that impaired insulin signaling, hypertriglyceridemia, and/or increased fatty acids, rather than impaired glucose tolerance or hypercholesterolemia, are responsible for the development of neuropathic changes associated with prediabetes.
Glucose stimulated insulin secretion: Effect of chronic acidosis and alkalosis in MIN6 cells
Authors: Gu Xiang Q , Ryu Julie , Sun Xiaolu , Yao Hang , Gavrialov Orit , Lu‐Bo Ying , Cirulli Vincenzo , Haddad Gabriel G.
Published: June 2021

In addition to exacerbating insulin resistance, obesity has been associated with obstructive sleep apnea and hypercapnia. To explore the underlying mechanisms of these latter phenomena on glucose‐stimulated insulin secretion, we explored the effect of CO2/HCO3−/pH alterations in mouse secretagogue‐responsive insulinoma cells MIN6 exposed to different extracellular pHs ([pH]o) for 6 days, and measured glucose‐stimulated insulin secretion (GSIS), and passive and active electrophysiological membrane properties. We found that 1) when the extracellular [pH]o was alkaline (7.9) (fixing CO2 concentration at 5% and increasing NaHCO3 concentrations from 18 to 50 mM) GSIS decreased significantly and this was accompanied by a significantly hyperpolarized Vm, decreased Ri and increase in rheobase; 2) by fixing NaHCO3 at 18 mM and increasing the CO2 concentration from 5% to 15%, there was no effect on GSIS, resting membrane potential (Vm), and input resistance (Ri); 3) a decrease in extracellular pH (a pH of 6.5 or below with 5% CO2 and 0 mM NaHCO3) inhibited GSIS, and this was accompanied by a significantly depolarized Vm, decreased Ri and increase in rheobase. We conclude that 1) although GSIS does not depend on extracellular pH when extracellular pH is between 7.1 and 7.7, GSIS decreased when pH was outside this range; 2) uncompensated extracellular pH by eliminating NaHCO3 reduces GSIS, and this may involve a chloride‐dependent mechanism. These findings have important implications for the management of insulin resistance and diabetes in obese patients.
Hyperglycemia protects the heart after myocardial infarction: aspects of programmed cell survival and cell death
Authors: Malfitano Christiane , Loureiro Tatiana Carolina Alba , Rodrigues Bruno , Sirvente Raquel , Rabechi Nara B , Lacchini Silvia , Curi Rui , Irigoyen Maria Claudia C
Published: June 2021

This study was designed to evaluate the role of diabetic hyperglycemia after myocardial infarction on cardiac function and on programmed cell survival and death in rats (Wistar) hearts divided into 4 groups: control (C), diabetic (D), myocardial infarction (MI) and diabetic myocardial infarction (DI). The size of MI, systolic and diastolic function by echocardiography, cytokines expression by ELISA (TNF‐α, IL‐1β, IL‐6 and IL‐10), gene expression by real time PCR (Bax, Fas, p53, Bcl‐2, HIF‐1a, VEGF and IL8r), caspase 3 activity by espectrofluorimetric assay, capillary density and fibrosis by histological analysis. The systolic function (ejection fraction and shortening) was improved by hyperglycemia in DI group although these changes were accompanied by maintenance of diastolic dysfunction (isovolumetric relaxation time and peak E deceleration time). Reduction of 36% in MI size, pro‐inflammatory cytokines reduction, apoptosis activation and increase in cell survival factors (HIF‐1a, VEGFa and IL8r) were observed after 15 days of myocardial infarction. Moreover the hyperglycemic status probably induced angiogenesis (increase of capillary density) before and after MI, accompanied by reduction in fibrosis. In conlusion, these results suggest greater plasticity and cellular resistance to ischemic injury induced by chronic diabetic hyperglycemia in heart rats.

Financial support: CNPq and CAPES
Development of congestive heart failure in mice with a null deletion of MAFbx
Authors: Matern Philip D , Li Ning , Hwee Darren T , Chiamvimonvat Nipavan , Bodine Sue C
Published: June 2021

The E3 ubiquitin ligases, MuRF1 and MAFbx, are selectively expressed in striated muscle, and are implicated in the regulation of both skeletal and cardiac muscle mass through mechanisms that are still being determined, but are thought to involve the targeting of specific proteins through poly‐ubiquitylation for degradation by the ubiquitin proteasome system. Studies on mice with a null deletion of either MuRF1 or MAFbx reveal no cardiac phenotype in young unchallenged mice of either knock out (KO) line. In this study, we examined the hearts of MuRF1 and MAFbx KO mice up to the age of 18 months, and found that MAFbx KO mice develop congestive heart failure and die prematurely between the ages of 16–18 months. In contrast, MuRF1 mice age normally and exhibit only a mild physiological enlargement of the heart. At 18m MAFbx KO mice have significant increases in heart and lung wet weights. Histological evaluation of mice at 18m revealed enlarged atria and ventricle, as well as, increased fibrosis in MAFbx KO compared to WT and MuRF1 KO mice. Further, MAFbx KO mice displayed a significant reduction in cardiac function relative to age‐matched WT mice as measured by a decrease in percentage of fractional shortening and left ventricle ejection fraction. This study demonstrates a significant divergence in the physiology of mice with deletions in either MuRF1 or MAFbx. Funding was provided by the Muscular Dystrophy Association.
Morphological and molecular development in python model of pathological cardiac hypertrophy
Authors: Secor Stephen M. , Wall Chris , Riquelme Cecilia , Leinwand Leslie
Published: June 2021

The Burmese python (Python molurus) experiences rapid physiological hypertrophy of the heart with feeding. Within days after consuming a meal equaling in mass to 25% of snake's body mass, heart mass will have increased by as much as 30%. Given the python's capacity for physiological hypertrophy, we are exploring whether a pathological model of cardiac hypertrophy can be generated by chronic pressure overload. To induce pressures overload, we ligated the python's left systemic artery, thereby diverting all left ventricular output through the right systemic artery. Ligation alone generated a 20% increase in ventricular mass. The combination of ligation and feeding resulted in a 32% increase in ventricular mass. Characteristic of pathological hypertrophy for mammals is an increase in cardiac fibrosis. We observed a 32% increase (P = 0.05) in the amount of fibrotic tissue for hearts from ligated pythons compared to hearts from fed non‐ligated snakes. Molecular markers for the pathological phenotype of mammalian cardiac hypertrophy include upregulation of gene expression for α‐isoform of skeletal muscle actin (α‐SA) and β‐MHC, and a decrease in expression for α‐MHC and SERCA2. Ligation generated the pathological response of an increase in α‐SA and β‐MHC expression, while at the same time non‐pathological responses of increased α‐MHC and SERCA2 expression. The python heart responds to pressure overload with a combination of physiological and pathological traits that may collectively deter the loss of cardiac performance. Support for this research has been provided by the National Science Foundation (IOS‐0466139 to SS) and Hiberna Corp.