Adipocyte endothelin B receptor activation inhibits adiponectin production and causes insulin resistance in obese mice.

AIMS: Endothelin-1 (ET-1) is elevated in patients with obesity and adipose tissue of obese mice fed high-fat diet (HFD); however, its contribution to the pathophysiology of obesity is not fully understood. Genetic loss of endothelin type B receptors (ETB) improves insulin sensitivity in rats and leads to increased circulating adiponectin, suggesting that ETB activation on adipocytes may contribute to obesity pathophysiology. We hypothesized that elevated ET-1 in obesity promotes insulin resistance by reducing the secretion of insulin sensitizing adipokines, via ETB receptor. METHODS: Male adipocyte-specific ETB receptor knockout (adETBKO), overexpression (adETBOX), or control littermates were fed either normal diet (NMD) or high-fat diet (HFD) for 8 weeks. RESULTS: RNA-sequencing of epididymal adipose (eWAT) indicated differential expression of over 5500 genes (p < 0.05) in HFD compared to NMD controls, and changes in 1077 of these genes were attenuated in HFD adETBKO mice. KEGG analysis indicated significant increase in metabolic signaling pathway. HFD adETBKO mice had significantly improved glucose and insulin tolerance compared to HFD control. In addition, adETBKO attenuated changes in plasma adiponectin, insulin, and leptin that is observed in HFD versus NMD control mice. Treatment of primary adipocytes with ET-1 caused a reduction in adiponectin production that was attenuated in cells pretreated with an ETB antagonist. CONCLUSION: These data indicate elevated ET-1 in adipose tissue of mice fed HFD inhibits adiponectin production and causes insulin resistance through activation of the ETB receptor on adipocytes.

Differentially Altered Metabolic Pathways in the Amygdala of Subjects with Schizophrenia, Bipolar Disorder and Major Depressive Disorder.

Background and hypothesis: A growing number of studies implicate a key role for metabolic processes in psychiatric disorders. Recent studies suggest that ketogenic diet may be therapeutically effective for subgroups of people with schizophrenia (SCZ), bipolar disorder (BPD) and possibly major depressive disorder (MDD). Despite this promise, there is currently limited information regarding brain energy metabolism pathways across these disorders, limiting our understanding of how brain metabolic pathways are altered and who may benefit from ketogenic diets. We conducted gene expression profiling on the amygdala, a key region involved in in the regulation of mood and appetitive behaviors, to test the hypothesis that amygdala metabolic pathways are differentially altered between these disorders. Study Design: We used a cohort of subjects diagnosed with SCZ, BPD or MDD, and non-psychiatrically ill control subjects (n=15/group), together with our bioinformatic 3-pod analysis consisting of full transcriptome pathway analysis, targeted pathway analysis, leading-edge gene analysis and iLINCS perturbagen analysis. Study Results: We identified differential expression of metabolic pathways in each disorder. Subjects with SCZ displayed downregulation of mitochondrial respiration and nucleotide metabolism pathways. In comparison, we observed upregulation of mitochondrial respiration pathways in subjects with MDD, while subjects with BPD displayed enrichment of pathways involved in carbohydrate metabolism. Several pathways associated with brain metabolism including immune system processes and calcium ion transport were also differentially altered between diagnosis groups. Conclusion: Our findings suggest metabolic pathways are differentially altered in the amygdala in these disorders, which may impact approaches for therapeutic strategies.

Molecular profiling of the hippocampus of children with autism spectrum disorder.

Several lines of evidence point to a key role of the hippocampus in Autism Spectrum Disorders (ASD). Altered hippocampal volume and deficits in memory for person and emotion related stimuli have been reported, along with enhanced ability for declarative memories. Mouse models have demonstrated a critical role of the hippocampus in social memory dysfunction, associated with ASD, together with decreased synaptic plasticity. Chondroitin sulfate proteoglycans (CSPGs), a family of extracellular matrix molecules, represent a potential key link between neurodevelopment, synaptic plasticity, and immune system signaling. There is a lack of information regarding the molecular pathology of the hippocampus in ASD. We conducted RNAseq profiling on postmortem human brain samples containing the hippocampus from male children with ASD (n = 7) and normal male children (3-14 yrs old), (n = 6) from the NIH NeuroBioBank. Gene expression profiling analysis implicated molecular pathways involved in extracellular matrix organization, neurodevelopment, synaptic regulation, and immune system signaling. qRT-PCR and Western blotting were used to confirm several of the top markers identified. The CSPG protein BCAN was examined with multiplex immunofluorescence to analyze cell-type specific expression of BCAN and astrocyte morphology. We observed decreased expression of synaptic proteins PSD95 (p < 0.02) and SYN1 (p < 0.02), increased expression of the extracellular matrix (ECM) protease MMP9 (p < 0.03), and decreased expression of MEF2C (p < 0.03). We also observed increased BCAN expression with astrocytes in children with ASD, together with altered astrocyte morphology. Our results point to alterations in immune system signaling, glia cell differentiation, and synaptic signaling in the hippocampus of children with ASD, together with alterations in extracellular matrix molecules. Furthermore, our results demonstrate altered expression of genes implicated in genetic studies of ASD including SYN1 and MEF2C.

Temporal shifts to the gut microbiome associated with cognitive dysfunction following high-fat diet consumption in a juvenile model of traumatic brain injury.

The gut-brain axis interconnects the central nervous system (CNS) and the commensal bacteria of the gastrointestinal tract. The composition of the diet consumed by the host influences the richness of the microbial populations. Traumatic brain injury (TBI) produces profound neurocognitive damage, but it is unknown how diet influences the microbiome following TBI. The present work investigates the impact of a chow diet versus a 60% fat diet (HFD) on fecal microbiome populations in juvenile rats following TBI. Twenty-day-old male rats were placed on one of two diets for 9 days before sustaining either a Sham or TBI via the Closed Head Injury Model of Engineered Rotational Acceleration (CHIMERA). Fecal samples were collected at both 1- and 9-days postinjury. Animals were cognitively assessed in the novel object recognition tests at 8 days postinjury. Fecal microbiota DNA was isolated and sequenced. Twenty days of HFD feeding did not alter body weight, but fat mass was elevated in HFD compared with Chow rats. TBI animals had a greater percentage of entries to the novel object quadrant than Sham counterparts, P < 0.05. The Firmicutes/Bacteroidetes ratio was significantly higher in TBI than in the Sham, P < 0.05. Microbiota of the Firmicutes lineage exhibited perturbations by both injury and diet that were sustained at both time points. Linear regression analyses were performed to associate bacteria with metabolic and neurocognitive endpoints. For example, counts of Lachnospiraceae were negatively associated with percent entries into the novel object quadrant. Taken together, these data suggest that both diet and injury produce robust shifts in microbiota, which may have long-term implications for chronic health.NEW & NOTEWORTHY Traumatic brain injury (TBI) produces memory and learning difficulties. Diet profoundly influences the populations of gut microbiota. Following traumatic brain injury in a pediatric model consuming either a healthy or high-fat diet (HFD), significant shifts in bacterial populations occur, of which, some are associated with diet, whereas others are associated with neurocognitive performance. More work is needed to determine whether these microbes can therapeutically improve learning following trauma to the brain.

Excess glucose or fat differentially affects metabolism and appetite-related gene expression during zebrafish embryogenesis.

Zebrafish embryos use their yolk sac reserve as the sole nutrient source during embryogenesis. The two main forms of energy fuel can be found in the form of glucose or fat. Zebrafish embryos were exposed to glucose or injected with free fatty acid/Triacylglycerol (FFA/TAG) into the yolk sac at 24 hpf. At 72 hpf, glucose exposed or FFA/TAG injected had differential effects on gene expression in embryos, with fat activating lipolysis and ß-oxidation and glucose activating the insulin pathway. Bulk RNA-seq revealed that more gene expression was affected by glucose exposure compared to FFA/TAGs injection. Appetite-controlling genes were also differently affected by glucose exposure or FFA/TAG injections. Because the embryo did not yet feed itself at the time of our analysis, gene expression changes occurred in absence of actual hunger and revealed how the embryo manages its nutrient intake before active feeding.

Sex and molecular differences in cardiovascular parameters at peak influenza disease in mice.

There is a growing interest in the detection of subtle changes in cardiovascular physiology in response to viral infection to develop better disease surveillance strategies. This is not only important for earlier diagnosis and better prognosis of symptomatic carriers but also useful to diagnose asymptomatic carriers of the virus. Previous studies provide strong evidence of an association between inflammatory biomarker levels and both blood pressure (BP) and heart rate (HR) during infection. The identification of novel biomarkers during an inflammatory event could significantly improve predictions for cardiovascular events. Thus, we evaluated changes in cardiovascular physiology induced in A/Puerto Rico/8/34 (PR8) influenza infections in female and male C57BL/6J mice and compared them with the traditional method of influenza disease detection using body weight (BW). Using radiotelemetry, changes in BP, HR, and activity were studied. Change in BW of infected females was significantly decreased from 5 to 13 days postinfection (dpi), yet alterations in normal physiology including loss of diurnal rhythm and reduced activity was observed starting at about 3 dpi for HR and 4 dpi for activity and BP; continuing until about 13 dpi. In contrast, males had significantly decreased BW 8 to 12 dpi and demonstrated altered physiological measurements for a shorter period compared with females with a reduction starting at 5 dpi for activity, 6 dpi for BP, and 7 dpi for HR until about 12 dpi, 10 dpi, and 9 dpi, respectively. Finally, females and males exhibited different patterns of inflammatory maker expression in lungs at peak disease by analyzing bulk RNA-sequencing data for lungs and Bio-plex cytokine assay for blood collected from influenza-infected and naïve C57BL/6J female and male mice at 7 dpi. In total, this study provides insight into cardiovascular changes and molecular markers to distinguish sex differences in peak disease caused by influenza virus infection.NEW & NOTEWORTHY This study performed longitudinal cardiovascular measurements of influenza viral infection and identified sex difference in both physiological and molecular markers at peak disease.

Race and Sex Differences in Vital Signs Associated with COVID-19 and Flu Diagnoses in Mississippi.

Early detection of viral infections, such as COVID-19 and flu, have potential to reduce risk of morbidity, mortality, and disease transmission through earlier intervention strategies. For example, detecting changes in vital signs have the potential to more rapidly diagnose respiratory virus diseases. The objective of this study was to utilize the University of Mississippi Medical Center's extensive clinical database (EPIC) to investigate associations between temperature, pulse rate, blood pressure (BP), and respiration rate in COVID-19 and flu diagnosed patients. Data from 1,363 COVID-19 (March 3, 2020, to February 27, 2021) and 507 flu (October 1, 2017, to September 30, 2018) diagnosed patients with reported demographic dimensions (age, first race, and sex) and office visit dimensions (BMI, diastolic BP, pulse rate, respiration rate, systolic BP, and temperature) was obtained, including day of diagnosis and additional encounter visits 60 days before and after first unique diagnosis. Patients with COVID-19 or flu were disproportionately obese, with 93% of COVID-19 and 79% of flu patients with BMI ≥ 30. Most striking, Black women 50-64 years of age disproportionately carried the burden of disease. At the time of diagnosis, temperature was significantly increased for all patients, yet pulse rate was only significantly increased for flu diagnosis, and BP was not significantly different in either. Our findings show the need for more complete demographic and office visit dimension data from patients during epidemic and pandemic events and support further studies needed to understand association between vital signs and predicting respiratory disease.

Nutrient composition influences the gut microbiota in chronic thoracic spinal cord-injured rats.

Chronic spinal cord injury (SCI) results in an increased predisposition to various metabolic problems that can be exacerbated by consuming a diet rich in calories and saturated fat. In addition, gastrointestinal symptoms have been reported after SCI, including intestinal dysbiosis of the gut microbiome. The effects of both diet and SCI on the gut microbiome of adult male Long Evans rats euthanized 16 wk after injury were investigated. The rats were either thoracic spinal contused or received sham procedures. After 12 wk of either a low-fat or high-fat diet, cecal contents were analyzed, revealing significant microbial changes to every taxonomic level below the kingdom level. Shannon α diversity analyses demonstrated a significant difference in diversity between the groups based on the surgical condition of the rats. SCI produced a unique signature of changes in commensal bacteria that were significantly different than Sham. Specific changes in commensal bacteria as a result of diet manipulation had high fidelity with reports in the literature, such as Clostridia, Thiohalorhabdales, and Pseudomonadales. In addition, novel changes in commensal bacteria were identified that are unique dietary influences on SCI. Linear regression analysis on body fat and lean mass showed that a consequence of chronic SCI produces uncoupled associations between some commensal bacteria and body composition. In conclusion, despite tightly controlling the protein content and varying the carbohydrate and fat contents, Sham and SCI rats respond uniquely to diet. These data provide potential direction for therapeutic modulation of the microbiome to improve health and wellness following SCI.

Pial Vessel-Associated Microglia/Macrophages Increase in Female Dahl-SS/Jr Rats Independent of Pregnancy History.

As the resident immune cells of the central nervous system, microglia have a wide range of functions such as surveillance, phagocytosis, and signaling through production of chemokines and cytokines. Recent studies have identified and characterized macrophages residing at the meninges, a series of layers surrounding the brain and spinal cord. While perivascular microglia within the brain parenchyma increase following chronic hypertension, there are no reports of changes at the meninges, and specifically, associated with the pial vasculature. Thus, we used female Sprague Dawley and Dahl salt-sensitive (SS/Jr) rat brains, stained for ionized calcium-binding adapter molecule (Iba1), and characterized microglia/macrophages associated with pial vessels in the posterior brain. Results indicate that Iba1+ pial vessel-associated microglia (PVAM) completely surrounded the vessels in brains from the Dahl-SS/Jr rats. PVAM density was significantly higher and distance between PVAMs lower in Dahl-SS/Jr compared to the Sprague Dawley rat brains. Pregnancy history did not affect these findings. While the functional role of these cells are not known, we contextualize our novel findings with that of other studies assessing or characterizing myeloid cells at the borders of the CNS (meninges and choroid plexus) and perivascular macrophages and propose their possible origin in the Dahl-SS/Jr model of chronic hypertension.

Periconceptional 1,3-butanediol supplementation suppresses the superimposed preeclampsia-like phenotype in the Dahl salt-sensitive rat.

Preeclampsia is a hypertensive pregnancy disorder with no treatment beyond management of symptoms and delivery of the fetus and placenta. Chronic hypertension increases the risk of developing superimposed preeclampsia. Previous reports showed that 1,3-butanediol attenuates hypertension in rodents; however, the therapeutic potential of 1,3-butanediol for the prevention of preeclampsia has not been investigated. This study tested the hypothesis that attenuating hypertension before pregnancy and through the placentation period via 1,3-butanediol prevents the onset of preeclampsia in female Dahl salt-sensitive (SS/Jr) rats. Female Dahl SS/Jr rats were divided into two groups: 1,3-butanediol treated (20% via drinking water) and control (ad libitum water). Both groups were maintained on low-salt rodent chow (Teklad 7034, 0.3% NaCl; n = 8/group). Animals were treated with 1,3-butanediol for 7 wk (baseline), mated, and treated through day 12 of pregnancy. 1,3-Butanediol treatment increased plasma ß-hydroxybutyrate (metabolite of 1,3-butanediol) that negatively correlated with maternal body weight in late pregnancy. Mean arterial pressure was lower in the treated group at baseline, early, and mid pregnancy, but no difference was observed in late pregnancy after treatment ended. Uterine artery resistance index (UARI) was reduced in the treated dams. No adverse fetal effects were observed, and there were no differences in pup weight or length. Placentas from treated dams had decreased vascular endothelial growth factor levels as well as decreased placental basal zone thickness and increased labyrinth zone thickness. These findings support the therapeutic role of physiological ketosis via 1,3-butanediol as a potential therapeutic approach for managing chronic hypertension, thereby preventing and mitigating adverse pregnancy outcomes associated with preeclampsia.NEW & NOTEWORTHY A ketogenic diet or increased ß-hydroxybutyrate levels can reduce hypertension, but the potential of 1,3-butanediol, a ß-hydroxybutyrate precursor, for treatment of preeclampsia is unknown. We hypothesized that attenuating hypertension before and during pregnancy via 1,3-butanediol prevents preeclampsia in Dahl Salt-sensitive rats. 1,3-Butanediol significantly lowered blood pressure and improved uterine artery resistance with no observable adverse fetal effects. Physiological ketosis via 1,3-butanediol may be a potential therapeutic approach for managing hypertension and mitigating adverse pregnancy outcomes.

Single cell RNA sequencing reveals ferritin as a key mediator of autoimmune pre-disposition in a mouse model of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a devastating autoimmune disorder characterized by failure of self-tolerance with resultant production of autoreactive antibodies. The etiology of this syndrome is complex, involving perturbations in immune cell signaling and development. The NZBWF1 mouse spontaneously develops a lupus-like syndrome and has been widely used as a model of SLE for over 60 years. The NZBWF1 model represents the F1 generation of a cross between New Zealand Black (NZB) and New Zealand White (NZW) mice. In order to better understand the factors that contribute to the development of autoimmunity, single cell RNA sequencing was conducted using the bone marrow from female NZBWF1 mice prior to the development of overt disease. The results were contrasted with single cell RNA sequencing results from the two parental strains. The expected findings of B cell abundance and upregulation, and evidence of interferon signaling were validated in this model. In addition, several novel areas of inquiry were identified. Most notably, the data showed a marked upregulation of the ferritin light chain across all cell types in the NZBWF1 mice compared to parental controls. This data can serve as a gene expression atlas of all hematopoietic cells in the NZBWF1 bone marrow prior to the development of autoimmunity.

Immunological comparison of pregnant Dahl salt-sensitive and Sprague-Dawley rats commonly used to model characteristics of preeclampsia.

The pregnant Dahl salt-sensitive (S) rat is an established preclinical model of superimposed spontaneous preeclampsia characterized by exacerbated hypertension, increased urinary protein excretion, and increased fetal demise. Because of the underlying immune system dysfunction present in preeclamptic pregnancies in humans, we hypothesized that the pregnant Dahl S rat would also have an altered immune status. Immune system activation was assessed during late pregnancy in the Dahl S model and compared with healthy pregnant Sprague-Dawley (SD) rats subjected to either a sham procedure or a procedure to reduce uterine perfusion pressure (RUPP). Circulating immunoglobulin and cytokine levels were measured by enzyme-linked immunosorbent assay (ELISA) and Milliplex bead assay, respectively, and percentages of circulating, splenic, and placental immune cells were determined using flow cytometry. The pregnant Dahl S rat exhibited an increase in CD4+ T cells, and specifically TNFα+CD4+ T cells, in the spleen compared with virgin Dahl S rats. The Dahl also had increased neutrophils and decreased B cells in the peripheral blood as compared with Dahl virgin rats. SD rats that received the RUPP procedure had increases in circulating monocytes and increased IFN-É£+CD4+ splenic T cells. Together these findings suggest that dysregulated T cell activity is an important factor in both the pregnant Dahl S rats and SD rats after the RUPP procedure.

The roles of borderline personality disorder symptoms and dispositional capability for suicide in suicidal ideation and suicide attempts: Examination of the COMT Val158Met polymorphism.

There is a need to identify the subset of individuals with borderline personality disorder (BPD) symptoms at greatest risk for transitioning from suicidal ideation to a suicide attempt. Contemporary models of suicide risk propose that the capability for suicide is necessary for moving from suicidal ideation to a suicide attempt. Few studies have examined dispositional capability factors for suicide, especially among individuals with BPD symptoms. One candidate may be the catechol-o-methyltransferase (COMT) Val158Met polymorphism given its influence on pain sensitivity and fear. This study examined the interactive relation of BPD symptoms and the COMT Val158Met polymorphism to suicidal ideation and suicide attempts. Fifty-nine treatment-seeking patients were recruited. Participants were administered a series of clinical interviews to evaluate BPD symptoms and suicidal thoughts and behaviors. Saliva samples were collected for genotyping. The relation between BPD symptoms and suicidal ideation was not influenced by the Val158Met polymorphism. However, among Val/Val carriers, the probability of a lifetime suicide attempt increased as BPD symptom severity increased. Findings provide preliminary support for the Val/Val variant as a dispositional factor that may increase risk for suicide attempts in BPD; however, results must be interpreted with caution until replication of findings occurs in larger samples.

Nephron-deficient HSRA rats exhibit renal injury with age but have limited renal damage from streptozotocin-induced hyperglycemia.

Hypertension and diabetes are the greatest factors influencing the progression of chronic kidney disease (CKD). Investigation into the role of nephron number in CKD alone or with hypertension has revealed a strong inverse relationship between the two; however, not much is known about the connection between nephron number and diabetic kidney disease. The heterogeneous stock-derived model of unilateral renal agenesis (HSRA) rat, a novel model of nephron deficiency, provides a unique opportunity to study the association between nephron number and hypertension and diabetes on CKD. HSRA rats exhibit failure of one kidney to develop in 50-75% of offspring, whereas the remaining offspring are born with two kidneys. Rats born with one kidney (HSRA-S) develop significant renal injury with age compared with two-kidney littermates (HSRA-C). The induction of hypertension as a secondary stressor leads to significantly more renal injury in HSRA-S compared with HSRA-C rats and nephrectomized HSRA-C (HSRA-UNX) rats. The present study sought to address the hypothesis that nephron deficiency in the HSRA rat would hasten renal injury in the presence of a secondary stressor of hyperglycemia. HSRA animals did not exhibit diabetes-related traits at any age; thus, streptozotocin (STZ) was used to induce hyperglycemia in HSRA-S, HSRA-C, and HSRA-UNX rats. STZ- and vehicle-treated animals were followed for 15 wk. STZ-treated animals developed robust hyperglycemia, but in contrast to the response to hypertension, neither HSRA-S nor HSRA-UNX animals developed proteinuria compared with vehicle treatment. In total, our data indicate that hyperglycemia from STZ alone does not have a significant impact on the onset or progression of injury in young one-kidney HSRA animals.NEW & NOTEWORTHY The HSRA rat, a novel model of nephron deficiency, provides a unique opportunity to study the association between nephron number and confounding cardiovascular complications that impact kidney health. Although hypertension was previously shown to exacerbate renal injury in young HSRA animals, diabetic hyperglycemia did not lead to worse renal injury, suggesting that nephron number has limited impact on kidney injury, at least in this model.

Whole genome transcriptome analysis of the stomach resected in human vertical sleeve gastrectomy: cutting more than calories.

Vertical sleeve gastrectomy (VSG) is a surgical weight loss procedure that resects 80% of the stomach, creating a tube linking the esophagus to the duodenum. Because of the efficacy and relative simplicity of VSG, it is preferred in the United States, with VSG currently at >61% of bariatric surgeries performed. Surprisingly, there has never been a complete molecular characterization of the human stomach greater curvature's fundus and corpus. Here we compare and contrast the molecular makeup of these regions. We performed a prospective cohort study to obtain gastric tissue samples from patients undergoing elective VSG. Paired fundus and corpus samples were obtained. Whole genome transcriptome analysis was performed by RNA sequencing (N = 10), with key findings validated by qPCR (N = 24). Participants were primarily female (95.8%) and White (79.15%). Mean body mass index, body weight, and age were 46.1 kg/m2, 121.6 kg, and 43.29 yr, respectively. Overall, 432 gene transcripts were significantly different between the fundus and the corpus (P < 0.05). A significant correlation was found between the RNA sequencing dataset and qPCR validation, demonstrating robust gene expression differences between the fundus and the corpus. Significant genes included progastricsin, acidic chitinase, and gastokine 1 and 2 in both the fundus and the corpus. Of the very highly expressed genes in both regions, 87% were present in both the stomach's fundus and corpus, indicating substantial overlap. Despite significant overlap in the greater curvature gene signature, regional differences exist within the fundus and the corpus. Given that the mechanism of VSG is partly unresolved, the potential that the resected tissue may express genes that influence long-term body weight regulation is unknown and could influence VSG outcomes.

Gestational gut microbial remodeling is impaired in a rat model of preeclampsia superimposed on chronic hypertension.

Preeclampsia is a progressive hypertensive disorder of pregnancy affecting 2%-8% of pregnancies globally. Preexisting chronic hypertension is a major risk factor associated with developing preeclampsia, and growing evidence suggests a role for the gut microbiome in the development of preeclampsia. However, neither alterations in the gut microbiome associated with preeclampsia nor the mechanisms involved are fully understood. In this study, we tested the hypothesis that normal gestational maternal gut microbiome remodeling is impaired in the Dahl salt-sensitive (Dahl S) rat model of superimposed preeclampsia. Gut microbiome profiles of pregnant Dahl S, normal pregnant Sprague-Dawley (SD), and matched virgin controls were assessed by 16S rRNA gene sequencing at baseline; during early, middle, and late pregnancy; and 1-wk postpartum. Dahl S rats had significantly higher abundance in Proteobacteria, and multiple genera were significantly different from SD rats at baseline. The pregnant SD displayed a significant increase in Proteobacteria and genera such as Helicobacter, but these were not different between pregnant and virgin Dahl S rats. By late pregnancy, Dahl S rats had significantly lower α-diversity and Firmicutes compared with their virgin Dahl S controls. ß-diversity was significantly different among groups (P < 0.001). KEGG metabolic pathways including those associated with short-chain fatty acids were different in Dahl S pregnancy but not in SD pregnancy. These results reveal an association between chronic hypertension and gut microbiome dysbiosis which may hinder pregnancy-specific remodeling in the gut microbial composition during superimposed preeclampsia.

Sept8/SEPTIN8 involvement in cellular structure and kidney damage is identified by genetic mapping and a novel human tubule hypoxic model.

Chronic kidney disease (CKD), which can ultimately progress to kidney failure, is influenced by genetics and the environment. Genes identified in human genome wide association studies (GWAS) explain only a small proportion of the heritable variation and lack functional validation, indicating the need for additional model systems. Outbred heterogeneous stock (HS) rats have been used for genetic fine-mapping of complex traits, but have not previously been used for CKD traits. We performed GWAS for urinary protein excretion (UPE) and CKD related serum biochemistries in 245 male HS rats. Quantitative trait loci (QTL) were identified using a linear mixed effect model that tested for association with imputed genotypes. Candidate genes were identified using bioinformatics tools and targeted RNAseq followed by testing in a novel in vitro model of human tubule, hypoxia-induced damage. We identified two QTL for UPE and five for serum biochemistries. Protein modeling identified a missense variant within Septin 8 (Sept8) as a candidate for UPE. Sept8/SEPTIN8 expression increased in HS rats with elevated UPE and tubulointerstitial injury and in the in vitro hypoxia model. SEPTIN8 is detected within proximal tubule cells in human kidney samples and localizes with acetyl-alpha tubulin in the culture system. After hypoxia, SEPTIN8 staining becomes diffuse and appears to relocalize with actin. These data suggest a role of SEPTIN8 in cellular organization and structure in response to environmental stress. This study demonstrates that integration of a rat genetic model with an environmentally induced tubule damage system identifies Sept8/SEPTIN8 and informs novel aspects of the complex gene by environmental interactions contributing to CKD risk.

Endothelial cell disruption drives increased blood-brain barrier permeability and cerebral edema in the Dahl SS/jr rat model of superimposed preeclampsia.

Preeclampsia is characterized by increases in blood pressure and proteinuria in late pregnancy, and neurological symptoms can appear in the form of headaches, blurred vision, cerebral edema, and, in the most severe cases, seizures (eclampsia). The causes for these cerebral manifestations remain unknown, so the use of animal models that mimic preeclampsia is essential to understanding its pathogenesis. The Dahl salt-sensitive (Dahl SS/jr) rat model develops spontaneous preeclampsia superimposed on chronic hypertension; therefore, we hypothesized that the Dahl SS/jr rat would display cerebrovascular features similar to those seen in human preeclampsia. Furthermore, we predicted that this model would allow for the identification of mechanisms underlying these changes. The pregnant Dahl SS/jr rat displayed increased cerebral edema and blood-brain barrier disruption despite tighter control of cerebral blood flow autoregulation and vascular smooth muscle myogenic tone. Analysis of cerebral endothelial cell morphology revealed increased opening of tight junctions, basement membrane dissolution, and vesicle formation. RNAseq analysis identified that genes related to endothelial cell tight junctions and blood-brain barrier integrity were differentially expressed in cerebral vessels from pregnant Dahl SS/jr compared with healthy pregnant Sprague Dawley rats. Overall, our data reveal new insights into mechanisms involved in the cerebrovascular dysfunction of preeclampsia.NEW & NOTEWORTHY This study uses the Dahl SS/jr rat as a preclinical model of spontaneous superimposed preeclampsia to demonstrate uncoupling of cerebral vascular permeability and blood-brain barrier disruption from cerebral blood flow autoregulatory dysfunction and myogenic tone. Additionally, the data presented in this study lay the foundational framework on which future experiments assessing specific transcellular transport components such as individual transporter protein expression and components of the vesicular transport system (caveolae) can be built to help reveal a potential direct mechanistic insight into the causes of cerebrovascular complications during preeclamptic pregnancies.

Regional heterogeneity in rat Peyer's patches through whole transcriptome analysis.

Peyer's patches are gut-associated lymphoid tissue located throughout the intestinal wall. Peyer's patches consist of highly organized ovoid-shaped follicles, classified as non-encapsulated lymphatic tissues, populated with B cells, T cells, macrophages, and dendritic cells and function as an organism's intestinal surveillance. Limited work compares the gene profiles of Peyer's patches derived from different intestinal regions. In the current study, we first performed whole transcriptome analysis using RNAseq to compare duodenal and ileal Peyer's patches obtained from the small intestine of Long Evans rats. Of the 12,300 genes that were highly expressed, 18.5% were significantly different between the duodenum and ileum. Using samples obtained from additional subjects (n = 10), we validated the novel gene expression patterns in Peyer's patches obtained from the three regions of the small intestine. Rats had a significantly reduced number of Peyer's patches in the duodenum in comparison to either the jejunum or ileum. Regional differences in structural, metabolic, and immune-related genes were validated. Genes such as alcohol dehydrogenase 1, gap junction protein beta 2, and serine peptidase inhibitor clade b, member 1a were significantly reduced in the ileum in comparison to other regions. On the other hand, genes such as complement C3d receptor type, lymphocyte cytosolic protein 1, and lysozyme C2 precursor were significantly lower in the duodenum. In summary, the gene expression pattern of Peyer's patches is influenced by intestinal location and may contribute to its role in that segment.

Nitric oxide and oxidative stress pathways do not contribute to sex differences in renal injury and function in Dahl SS/Jr rats.

The burden of hypertension in the United States is increasing and yields significant morbidity and mortality, and sex differences in hypertension are widely recognized. Reduced nitric oxide (NO) bioavailability and increased oxidative stress are known to contribute to the pathogenesis of hypertensive renal injury, and but their contributions to sex differences in injury progression of are undefined. Our purpose was to test the hypothesis that male hypertensive rats have accelerated renal injury compared to females and to determine the contributions of the nitric oxide pathway and oxidative stress in these differences. Male and female Dahl SS/Jr rats, a model that spontaneously develops hypertension with age, were allowed to age on a 0.3% NaCl diet until 3 or 6 months of age, at which points blood pressure was measured and plasma, tissue, and urine were collected. While no significant sex differences in blood pressure were present at either time point, renal injury measured by urine protein excretion was more severe (male = 44.9 ± 6; female = 15±3 mg/day/100 g bw, p = .0001), and renal function was reduced (male = 0.48 ± 0.02; female = 0.7 ± 0.03 ml min-1  g-1 kw, p = .001) in males compared to females with age. Both male and female rats exhibited reduced nitric oxide metabolites (3 months: male = 0.65 ± 0.1; female = 0.74 ± 0.3; 6 months: male = 0.16 ± 0.1; female = 0.41 ± 0.1 ml min-1  g-1 kw, p, age = 0.02, p, sex = 0.3). Levels of urinary TBARS were similar (3 months: male = 20±1.5; female = 23±1.8; 6 months: male = 26±4.8; female = 23±4.7µM day g-1 kw, p, age = 0.4, p, sex = 0.9), extracellular superoxide dismutase (EC SOD) mRNA was greater in females (3 months: male = 0.35 ± 0.03; female = 1.4 ± 0.2; 6 months: male = 0.4 ± 0.05; female = 1.3 ± 0.1 normalized counts, p, age = 0.7, p, sex < 0.0001), but EC SOD protein expression was not different (3 months: male = 0.01 ± 0.002; female = 0.01 ± 0.002; 6 months: male = 0.02 ± 0.004; female = 0.01 ± 0.002 relative density, p, age = 0.2, p, sex = 0.8). These data support the presence of significant sex differences in renal injury and function in the Dahl S rat and identify a need for further study into the mechanisms involved.