Allelic Variants in Arhgef11 via the Rho-Rock Pathway Are Linked to Epithelial-Mesenchymal Transition and Contributes to Kidney Injury in the Dahl Salt-Sensitive Rat

Six Decades of History of Hypertension Research at the University of Toledo: Highlighting Pioneering Contributions in Biochemistry, Genetics, and Host-Microbiota Interactions

PURPOSE OF REVIEW

The study aims to capture the history and lineage of hypertension researchers from the University of Toledo in Ohio and showcase their collective scientific contributions dating from their initial discoveries of the physiology of adrenal and renal systems and genetics regulating blood pressure (BP) to its more contemporary contributions including microbiota and metabolomic links to BP regulation.

RECENT FINDINGS

The University of Toledo College of Medicine and Life Sciences (UTCOMLS), previously known as the Medical College of Ohio, has contributed significantly to our understanding of the etiology of hypertension. Two of the scientists, Patrick Mulrow and John Rapp from UTCOMLS, have been recognized with the highest honor, the Excellence in Hypertension award from the American Heart Association for their pioneering work on the physiology and genetics of hypertension, respectively. More recently, Bina Joe has continued their legacy in the basic sciences by uncovering previously unknown novel links between microbiota and metabolites to the etiology of hypertension, work that has been recognized by the American Heart Association with multiple awards. On the clinical research front, Christopher Cooper and colleagues lead the CORAL trials and contributed importantly to the investigations on renal artery stenosis treatment paradigms. Hypertension research at this institution has not only provided these pioneering insights, but also grown careers of scientists as leaders in academia as University Presidents and Deans of Medical Schools. Through the last decade, the university has expanded its commitment to Hypertension research as evident through the development of the Center for Hypertension and Precision Medicine led by Bina Joe as its founding Director. Hypertension being the top risk factor for cardiovascular diseases, which is the leading cause of human mortality, is an important area of research in multiple international universities. The UTCOMLS is one such university which, for the last 6 decades, has made significant contributions to our current understanding of hypertension. This review is a synthesis of this rich history. Additionally, it also serves as a collection of audio archives by more recent faculty who are also prominent leaders in the field of hypertension research, including John Rapp, Bina Joe, and Christopher Cooper, which are cataloged at Interviews .

Role of noncoding RNA in the pathophysiology and treatment of intrauterine adhesion

Intrauterine adhesion (IUA) is one of the most common diseases of the reproductive system in women. It is often accompanied by serious clinical problems that damage reproductive function, such as menstrual disorder, infertility, or recurrent abortion. The clinical effect of routine treatment is not ideal, and the postoperative recurrence rate is still very high. Therefore, exploring the pathological mechanism of IUA and finding new strategies for the effective prevention and treatment of IUA are needed. The main pathological mechanism of IUA is endometrial fibrosis and scar formation. Noncoding RNA (ncRNA) plays an important role in the fibrosis process, which is one of the latest research advances in the pathophysiology of IUA. Moreover, the exosomal miRNAs derived from mesenchymal stem cells can be used to improve IUA. This paper reviewed the role of ncRNAs in IUA pathogenesis, summarized the core pathways of endometrial fibrosis regulated by ncRNAs, and finally introduced the potential of ncRNAs as a therapeutic target.

Research on the Mechanism and Prevention of Hypertension Caused by Apatinib Through the RhoA/ROCK Signaling Pathway in a Mouse Model of Gastric Cancer

Hypertension is one of the main adverse effects of antiangiogenic tumor drugs and thus limits their application. The mechanism of hypertension caused by tyrosine kinase inhibitors (TKIs) targeting vascular endothelial growth factors is mainly related to inhibition of the nitric oxide (NO) pathway and activation of the endothelin pathway, as well as vascular rarefaction and increased salt sensitivity; consequently, prevention and treatment differ for this type of hypertension compared with primary hypertension. Apatinib is a highly selective TKI approved in China for the treatment of advanced or metastatic gastric cancer. The RhoA/ROCK pathway is involved in the pathogenesis of hypertension and mediates smooth muscle contraction, eNOS inhibition, endothelial dysfunction and vascular remodeling. In this study, in vivo experiments were performed to explore whether the RhoA/ROCK signaling pathway is part of a possible mechanism of apatinib in the treatment of gastric cancer-induced hypertension and the impairment of vascular remodeling and left ventricular function. Y27632, a selective small inhibitor of both ROCK1 and ROCK2, was combined with apatinib, and its efficacy was evaluated, wherein it can reduce hypertension induced by apatinib treatment in gastric cancer mice and weaken the activation of the RhoA/ROCK pathway by apatinib and a high-salt diet (HSD). Furthermore, Y-27632 improved aortic remodeling, fibrosis, endothelial dysfunction, superior mesenteric artery endothelial injury, left ventricular dysfunction and cardiac fibrosis in mice by weakening the activation of the RhoA/ROCK pathway. The expression of RhoA/ROCK pathway-related proteins and relative mRNA levels in mice after apatinib intervention were analyzed by various methods, and blood pressure and cardiac function indexes were compared. Endothelial and cardiac function and collagen levels in the aorta were also measured to assess vascular and cardiac fibrosis and to provide a basis for the prevention and treatment of this type of hypertension.

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.

Therapeutic Potential of Exosomes in Pulmonary Fibrosis

Pulmonary fibrosis is closely associated with the recruitment of fibroblasts from capillary vessels with damaged endothelial cells, the epithelial mesenchymal transition (EMT) of type II alveolar epithelial cells, and the transformation of fibroblasts to myofibroblasts. Recent studies suggest that EMT is a key factor in the pathogenesis of pulmonary fibrosis, as the disruption of EMT-related effector molecules can inhibit the occurrence and development of PF. With the numerous advancements made in molecular biology in recent years, researchers have discovered that exosomes and their cargos, such as miRNAs, lncRNAs, and proteins, can promote or inhibit the EMT, modulate the transformation of fibroblasts into myofibroblasts, contribute to the proliferation of fibroblasts and promote immunoregulatory and mitochondrial damage during pulmonary fibrosis. Exosomes are key factors regulating the differentiation of bone marrow mesenchymal stem cells (BMSCs) into myofibroblasts. Interestingly, exosomes derived from BMSCs under pathological and physiological conditions may promote or inhibit the EMT of type II alveolar epithelial cells and the transformation of fibroblasts into myofibroblasts to regulate pulmonary fibrosis. Thus, exosomes may become a new direction in the study of drugs for the treatment of pulmonary fibrosis.

Loss of Arhgef11 in the Dahl Salt-Sensitive Rat Protects Against Hypertension-Induced Renal Injury

Arhgef11 is a Rho-guanine nucleotide exchange factor that was previously implicated in kidney injury in the Dahl salt-sensitive (SS) rat, a model of hypertension-related chronic kidney disease. Reduced Arhgef11 expression in an SS-Arhgef11^SHR-minimal congenic strain (spontaneously hypertensive rat allele substituted for S allele) significantly decreased proteinuria, fibrosis, and improved renal hemodynamics, without impacting blood pressure compared with the control SS (SS-wild type). Here, SS-Arhgef11^-/- and SS-wild type rats were placed on either low or elevated salt (0.3% or 2% NaCl) from 4 to 12 weeks of age. On low salt, starting at week 6 and through week 12, SS-Arhgef11^-/- animals demonstrated a 3-fold decrease in proteinuria compared with SS-wild type. On high salt, beginning at week 6, SS-Arhgef11^-/- animals demonstrated >2-fold lower proteinuria from weeks 8 to 12 and 30 mm Hg lower BP compared with SS-wild type. To better understand the molecular mechanisms of the renal protection from loss of Arhgef11, both RNA sequencing and discovery proteomics were performed on kidneys from week 4 (before onset of renal injury/proteinuria between groups) and at week 12 (low salt). The omics data sets revealed loss of Arhgef11 (SS-Arhgef11^-/-) initiates early transcriptome/protein changes in the cytoskeleton starting as early as week 4 that impact a number of cellular functions, including actin cytoskeletal regulation, mitochondrial metabolism, and solute carrier transporters. In summary, in vivo phenotyping coupled with a multi-omics approach provides strong evidence that increased Arhgef11 expression in the Dahl SS rat leads to actin cytoskeleton-mediated changes in cell morphology and cell function that promote kidney injury, hypertension, and decline in kidney function.

The protective role of estrogen and its receptors in gentamicin-induced acute kidney injury in rats

AIM

Investigating the impact of 17β-Estradiol/estrogen receptors in gentamicin-induced nephrotoxicity.

MAIN METHODS

Three weeks post-ovariectomy or sham surgery for the Wistar albino female rats, thirty sham rats were randomly grouped (n = 6), received either vehicle or gentamicin; the estrogen receptors down regulator (fulvestrant); gentamicin plus fulvestrant; gentamicin plus the phytoestrogen (genistein). Forty-eight ovariectomized rats were randomly grouped (n = 6), treated with either vehicle or gentamicin; fulvestrant; gentamicin plus fulvestrant; genistein; gentamicin plus genistein; estradiol benzoate; gentamicin plus estradiol benzoate. Just post-treatment termination, the traditional kidney injury biomarkers (serum creatinine and blood urea nitrogen) and novel biomarkers (serum Kidney injury molecule -1, cystatin C, lactate dehydrogenase and, gamma-glutamyl transferase) were determined. Bovine serum albumin labeled with fluorescence isothiocyanate assessed megalin expression/endocytic functionality in the proximal tubules epithelial cells (PTECs). The immunohistochemical investigation for the same-sectioned slides of PTECs assessed the correlation between estrogen receptors α and megalin receptors expression. Histopathological examination of PTECs and subjective scoring system graded the damage markers.

KEY FINDINGS

Estrogen receptor α expression was markedly dimensioned post-ovariectomy, co-localized and inversely correlated to megalin expression. Serum levels of the novel biomarkers were directly proportional to megalin expression in the PTECs and inversely correlated with estrogen receptor α expression. The injury was exaggerated in ovariectomized and intact rats received fulvestrant. Supplementation with estrogen or genistein ameliorated this injury.

SIGNIFICANCE

Estrogen/estrogen receptors have a protective impact on gentamicin-induced acute kidney injury. Estrogen receptors antagonist exacerbate the injury, and oppositely, estrogens or phytoestrogens improve it.

MicroRNA-1291 promotes endometrial fibrosis by regulating the ArhGAP29-RhoA/ROCK1 signaling pathway in a murine model

Intrauterine adhesions (IUAs) are caused by endometrial damage and are associated with a poor pregnancy prognosis including infertility, oligomenorrhea and recurrent pregnancy loss. Understanding the pathogenesis of IUAs may help prevent and treat this condition more effectively. The aim of the current study was to investigate the function of microRNA-1291 (miR-1291) during the development of IUAs following endometrial damage and elucidate the potential molecular mechanisms involved. The expression of Rho GTPase activating protein 29 (ArhGAP29), a putative target mRNA of miR-1291, was determined by immunohistochemical staining of human endometrial tissue from patients with IUAs and compared with normal endometrial tissues. ArhGAP29 expression was significantly decreased in endometrial tissues with IUAs compared with normal endometrium. Additionally, a murine IUAs model was developed and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) demonstrated that miR-1291 levels were significantly increased in the uterine tissue and plasma of the IUAs group compared with the normal mice. Furthermore, an miR-1291 antagomir was injected into the uterine cavity of experimental IUAs mice to block miR-1291. Hematoxylin and eosin and Masson's stain revealed that blocking miR-1291 significantly ameliorated endometrial fibrosis. Furthermore, levels of epithelial mesenchymal transition (EMT)-associated proteins, and ArhGAP29-RhoA/Rho-associated coiled coil containing protein kinase 1 (ROCK1) were measured in uterine tissue by western blot, RT-qPCR analysis and immunofluorescence staining. Levels of the mesenchymal marker proteins, vimentin and N-cadherin, were increased in the IUAs group mice, accompanied by a relative decrease in the epithelial marker proteins, cytokeratin and E-cadherin compared with normal murine endometrium. miR-1291 inhibition decreased RhoA/ROCK1 expression in the EMT pathway, but increased ArhGAP29 expression. Taken together, the findings indicate that miR-1291 acts upstream of ArhGAP29 to negatively regulate the RhoA/ROCK1 EMT pathway, ultimately leading to endometrial fibrosis. These studies may provide new potential therapeutic options and pave the way to use circulating miR-1291 as a clinical biomarker of endometrial fibrosis.

Effect of RhoC on the epithelial-mesenchymal transition process induced by TGF-β1 in lung adenocarcinoma cells

According to recent research, Ras homolog gene family member C (RhoC) is confirmed to have a powerful regulatory effect on cell motility mediated by the cytoskeleton, and this process is closely associated with tumor invasion and metastasis. In addition, the epithelial-mesenchymal transition (EMT) process which causes cytoskeleton rearrangement, also plays a pivotal role in tumor invasion and metastasis.Consequently, in the present study, we aimed to ascertain whether RhoC has an effect on the EMT process induced by TGF-β1 in lung adenocarcinoma cells and whether RhoC promotes tumor invasion by mediating the occurrence of EMT. Based on the findings, we demonstrated that RhoC was an essential mediator of the EMT process in lung adenocarcinoma cell line A549 which was evaluated by observing the morphological characteristics of the cells and by assessing the expression levels of two EMT marker proteins: E-cadherin and vimentin. During the process of EMT in the A549 cells induced by TGF-β1 (5 ng/ml), upregulated RhoC protein and RhoC activity were detected, which was associated with the enhanced invasive capability of the cells in vitro. Conversely, downregulation of the expression of RhoC by shRNA markedly impeded EMT progression as well as the invasion of A549 cells. Our results may provide a novel target towards the prevention of metastasis in advanced lung adenocarcinoma.

Links between coagulation, inflammation, regeneration, and fibrosis in kidney pathology

Acute kidney injury (AKI) involves nephron injury leading to irreversible nephron loss, ie, chronic kidney disease (CKD). Both AKI and CKD are associated with distinct histological patterns of tissue injury, but kidney atrophy in CKD involves tissue remodeling with interstitial inflammation and scarring. No doubt, nephron atrophy, inflammation, fibrosis, and renal dysfunction are associated with each other, but their hierarchical relationships remain speculative. To better understand the pathophysiology, we provide an overview of the fundamental danger response programs that assure host survival upon traumatic injury from as early as the first multicellular organisms, ie, bleeding control by coagulation, infection control by inflammation, epithelial barrier restoration by re-epithelialization, and tissue stabilization by mesenchymal repair. Although these processes assure survival in the majority of the populations, their dysregulation causes kidney disease in a minority. We discuss how, in genetically heterogeneous population, genetic variants shift balances and modulate danger responses toward kidney disease. We further discuss how classic kidney disease entities develop from an insufficient or overshooting activation of these danger response programs. Finally, we discuss molecular pathways linking, for example, inflammation and regeneration or inflammation and fibrosis. Understanding the causative and hierarchical relationships and the molecular links between the danger response programs should help to identify molecular targets to modulate kidney injury and to improve outcomes for kidney disease patients.