scholarly journals Role of TLR4/MyD88 Signaling Pathway in the Occurrence and Development of Uremia-Induced Myocardial Hypertrophy and Possible Mechanism

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Huiping Zhu ◽  
Liutong Pan ◽  
Yuanting Dai ◽  
Dan Zheng ◽  
Shasha Cai

The morbidity and mortality of cardiovascular disease (CVD) are relatively high. Studies have shown that most patients with chronic kidney disease (CKD) die from cardiovascular complications. Clinically, the pathophysiological state in which heart disease and kidney disease are causal and influence each other is called cardiorenal syndrome (CRS). Myocardial hypertrophy is the key stage of the heart structure changing from reversible to irreversible. It is an important pathophysiological basis for heart failure. Therefore, this study intends to start with the end-stage uremic phase of CKD to construct an animal model of uremia in rats to study the relationship between uremia, TLR4/MyD88 signaling pathway, and myocardial hypertrophy. The results showed that the uremic rats showed slow weight gain and were thinner. At 12 weeks (w), the serum creatinine and urea nitrogen of the uremic rats increased, and the global hypertrophy index increased. Detecting the expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor (MyD88) in blood samples of rats, we found that the expression of TLR4 and MyD88 increased at 12 w in the uremia group; pathological observation showed that at 4 weeks of uremia model rats, renal tissue compensatory hypertrophy, renal fibrous membrane proliferation, renal parenchyma atrophy, a large number of fibrous proliferation and inflammatory cell infiltration in the interstitium, and protein casts in the renal tubules were observed. Myocardial cells were obviously hypertrophy and disordered. At 12 w, renal tubules were obviously expanded, the epithelium was flat, the brush border disappeared, and the interstitial fibrous connective tissue of the myocardial tissue was proliferated. The detection of TLR4 and MyD88 in kidney tissue and myocardial tissue revealed that the positive expression of TLR4 and MyD88 gradually increased over time. Therefore, the final result of the study is that uremia can gradually lead to myocardial hypertrophy and TLR4 and MyD88 are highly expressed in serum, kidney, and myocardial tissues of uremic rats, suggesting that TLR4 and MyD88 may be related to the degree of uremic disease and the myocardium caused by it. Hypertrophy is related.

2013 ◽  
Vol 124 (12) ◽  
pp. 709-717 ◽  
Author(s):  
Chaodong Fang ◽  
Lei Shen ◽  
Liang Dong ◽  
Meng Liu ◽  
Sensen Shi ◽  
...  

Corin is a cardiac protease that regulates BP (blood pressure) by activating natriuretic peptides. Recent animal studies identified corin expression in the kidney where it may regulate renal function. In the present study, we tested the hypothesis that corin may be present in human urine and that urinary corin levels may be altered in patients with kidney disease. We obtained urine and kidney tissue samples from normal individuals and CKD (chronic kidney disease) patients. Using ELISA, we detected corin protein in human urine. In normal individuals, urinary corin levels did not correlate with that of plasma, indicating that urinary corin is probably of kidney origin. Compared with normal controls, CKD patients had markedly reduced urinary corin levels and this reduction correlated with disease severity. By immunostaining, human corin protein was identified on the epithelial cell surface in renal tubules. The renal corin mRNA and protein levels were significantly lower in CKD patients than non-CKD controls. The results indicate that renal tubular corin may be shed into urine and that urinary and renal corin levels were reduced in CKD patients. These data suggest that reduced corin levels in the kidney may reflect the underlying pathology in CKD.


2022 ◽  
Vol 2022 ◽  
pp. 1-7
Author(s):  
Suhua Li ◽  
Xuan Huang ◽  
Shun Wang ◽  
Xueqian Chu ◽  
Munire Aierken

Background. Ischemia-reperfusion acute kidney injury (I/R AKI) is a severe kidney disease with high mortality and morbidity. This study aimed to explore the protective mechanism of glutamine (GLN) against I/R AKI. Methods.The I/R AKI rat model was established, and HE staining of kidney tissue and serum creatinine (SCr) and blood urea nitrogen (BUN) detection were performed. The miRNAs were sequenced by high throughput in rat kidney tissue samples. Differentially expressed miRNAs (DEmiRs) between the I/R group and I/R + GLN group were screened, and enrichment analysis for target genes of DEmiRs was performed. Meanwhile, human HK-2 cells were cultured, and an I/R model was established to verify the expression of DEmiRs. Results. Compared with the I/R group, the SCr and BUN levels at each time point were lower in the I/R + GLN group. Vacuolar degeneration of renal tubules in the I/R + GLN group was significantly reduced. In the 104 DEmiRs, we selected miR-132-5p, miR-205, and miR-615 as key miRNAs. KEGG analysis showed that the Notch signaling pathway, PI3K-Akt signaling pathway, and cGMP signaling pathway were mainly related to the GLN against I/R. qRT-PCR verified the downregulation of miR-205 in the I/R group, compared to the sham and I/R + GLN group. The I/R model was established with HK-2 cells, and the expression of miR-132-5p and miR-205 was decreased. Conclusion. GLN reduced I/R-induced AKI. There were significant differences between miRNAs expression in I/R after GLN treatment. The process of GLN against I/R-induced AKI may be related to the Notch and PI3K-Akt signaling pathway.


2021 ◽  
Author(s):  
Jianshu Chen ◽  
Jing Yu ◽  
Ruowen Yuan ◽  
Ningyin Li ◽  
Caie Li ◽  
...  

Compelling evidence have described the incidence of hypertension and left ventricular hypertrophy (LVH) in postmenopausal women is significantly increased worldwide. Our team’s previous research identified that androgen was an underlying factor contributing to increased blood pressure and LVH in postmenopausal women. However, little is known about how androgens affect LVH in postmenopausal hypertensive women. The purpose of this study was to evaluate the role of mTOR signaling pathway in myocardial hypertrophy in androgen-induced postmenopausal hypertension and whether mTOR inhibitors can protect the myocardium from androgen-induced interference to prevent and treat cardiac hypertrophy. For that, ovariectomized (OVX) spontaneously hypertensive rats (SHR) aged 12 weeks were used to study the effects of testosterone (T 2.85 mg/kg/weekly im) on blood pressure and myocardial tissue. On the basis of antihypertensive therapy (chlorthalidone 8mg/kg/day ig), the improvement of blood pressure and myocardial hypertrophy in rats treated with different dose gradients of rapamycin (0.8mg/kg/day Vs 1.5mg/kg/day Vs 2mg/kg/day ip) in OVX+ estrogens(E 9.6 mg/Kg/day, ig)+T group was further evaluated. After T intervention, the OVX female rats exhibited significant increments in the heart weight / tibial length (TL), area of cardiomyocytes and the mRNA expressions of atrial natriuretic peptide, β- myosin heavy chain and matrix metalloproteinase 9 accompanied by a significant reduction in the uterine weight/TL and issue inhibitor of metalloproteinase 1. Mammalian rapamycin receptor (mTOR), ribosomal protein S6 kinase (S6K1),4E-bindiong protein 1(4EBP1) and eukaryotic translation initiation factor 4E in myocardial tissue of OVX+E+T group were expressed at higher levels than those of the other four groups. On the other hand, rapamycin abolished the effects of T-induced cardiac hypertrophy, decreased the systolic and diastolic blood pressure of SHR, and inhibited the activation of mTOR/ S6K1/4EBP1 signaling pathway in a concentration-dependent manner. Collectively, these data suggest that the mTOR/S6K1/4EBP1 pathway is an important therapeutic target for the prevention of LVH in postmenopausal hypertensive female rats with high T levels. Our findings also support the standpoint that the mTOR inhibitor, rapamycin, can eliminate T-induced cardiomyocyte hypertrophy


2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Tomoaki Takata ◽  
Kohshiro Hosokawa ◽  
Takaaki Sugihara ◽  
Tomomitsu Matono ◽  
Masahiko Koda ◽  
...  

Abstract Background and Aims Chronic kidney disease (CKD) is a major health issue closely related to metabolic syndrome. Although a potential link between ectopic lipid-induced ER stress and the progression of CKD has been suggested, the underlying mechanism has not yet been fully elucidated. SGLT2 inhibitors have been reported to be effective in reducing fat accumulation. However the effect on lipid-associated kidney disease remains unclear. The aim of this study was to investigate the role of ectopic lipid and ER stress in the development of CKD, and evaluate the efficacy of an SGLT2 inhibitor. Method FLS-ob/ob mice, a model that shows significant ectopic lipid deposition and closely imitate the pathophysiology of non-alcoholic steatohepatitis, were treated with vehicle or an SGLT2 inhibitor, Ipragliflozin (1 mg/kg body weight) for 12 weeks. Metabolic characteristics, histology of the kidney, ER stress and apoptotic signals were evaluated. Results Ipragliflozin significantly reduced the serum triglyceride level. Ectopic lipid deposition in renal tubules found in FLS-ob/ob mice was prevented by Ipragliflozin, accompanied by reduced interstitial fibrosis. Both GRP78, a master regulator or ER stress, and CHOP, a downstream mediator of ER stress, were significantly downregulated in mice treated with Ipragliflozin. Apoptotic signal in kidney tissue was also reduced. Conclusion Ipragliflozin improved the pathogenesis of CKD by reducing ER stress through preventing ectopic lipid deposition in the kidney. SGLT2 inhibitors may have therapeutic effect on lipid-associated kidney disease.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yi Zhang ◽  
Shaohua Yang ◽  
Xiao Cui ◽  
Juhong Yang ◽  
Miaoyan Zheng ◽  
...  

Aims. We investigated the changes of renal structure and its function in normal glucose tolerance (NGT), impaired glucose tolerance (IGT), diabetes mellitus (DM), and diabetic kidney disease (DKD) stages in OLETF rats and explored the role of the INS/IRS-1/PI3-K/Akt signaling pathway. Methods. OLETF rats were assigned into four groups on the basis of OGTT results and 24 h urinary microalbumin: NGT, IGT, DM, and DKD groups. The changes of renal structure and function and the corresponding pathological changes were observed. The absorption of albumin and the expression of megalin, cubilin, IRS-1, PI3-K, and Akt in NRK-52E cells were measured after being stimulated by different concentrations of insulin. Results. In the IGT group, the index which reflects the function of renal tubule-like N-acetyl-β-glucosaminidase, neutrophil gelatinase-associated lipocalin, retinol-binding protein, and cystatin C was higher than those in the control group and the NGT group (P<0.05). Significant renal structure damages, especially in renal tubules, were observed in the IGT group. In the presence of insulin at a high concentration, the IRS-1/PI3-K/Akt signaling pathway in renal tubular epithelial cells was inhibited, and the expression of megalin and cubilin was significantly downregulated which was accompanied by a minimum uptake of albumin. Conclusions. In contrast to DKD, the renal structural damage and functional changes in the IGT stage, in which we propose the term “IGT kidney disease,” mainly manifest as renal tubular injury. Insulin resistance and compensatory hyperinsulinemia may be involved in its pathogenesis.


2019 ◽  
Vol 17 (3) ◽  
pp. 329-336
Author(s):  
Wang Jinli ◽  
Xu Fenfen ◽  
Zheng Yuan ◽  
Cheng Xu ◽  
Zhang Piaopiao ◽  
...  

Cardiovascular disease including cerebral ischemic stroke is the major complication that increases the morbidity and mortality in patients with diabetes mellitus as much as four times. It has been well established that irisin, with its ability to regulate glucose and lipid homeostasis as well as anti-inflammatory and anti-apoptotic properties, has been widely examined for its therapeutic potentials in managing metabolic disorders. However, the mechanism of irisin in the regulation of cerebral ischemic stroke remains unclear. Using PC12 cells as a model, we have shown that hypoxia/reoxygenation inhibits cell viability and increases lactic dehydrogenase. Irisin, in a dose-dependent manner, reversed these changes. The increase in inflammatory mediators (IL-1β, IL-6, and TNF-α) by hypoxia/reoxygenation was reversed by irisin. Furthermore, the cell apoptosis promoted by hypoxia/reoxygenation was also inhibited by irisin. Irisin suppressed TLR4/MyD88 signaling pathway leading to amelioration of inflammation and apoptosis in PC12 cells. Thus, inhibition of TLR4/MyD88 signaling pathway via irisin could be an important mechanism in the regulation of hypoxia/reoxygenation-induced inflammation and apoptosis in PC12 cells.


2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Bohan Chen ◽  
Pei Wang ◽  
Xianhui Liang ◽  
Chunming Jiang ◽  
Yan Ge ◽  
...  

AbstractRenal tubular epithelial cells (TECs) play a key role in renal fibrogenesis. After persistent injuries that are beyond self-healing capacity, TECs will dedifferentiate, undergo growth arrest, convert to profibrogenic phenotypes, and resort to maladaptive plasticity that ultimately results in renal fibrosis. Evidence suggests that glycogen synthase kinase (GSK) 3β is centrally implicated in kidney injury. However, its role in renal fibrogenesis is obscure. Analysis of publicly available kidney transcriptome database demonstrated that patients with progressive chronic kidney disease (CKD) exhibited GSK3β overexpression in renal tubulointerstitium, in which the predefined hallmark gene sets implicated in fibrogenesis were remarkably enriched. In vitro, TGF-β1 treatment augmented GSK3β expression in TECs, concomitant with dedifferentiation, cell cycle arrest at G2/M phase, excessive accumulation of extracellular matrix, and overproduction of profibrotic cytokines like PAI-1 and CTGF. All these profibrogenic phenotypes were largely abrogated by GSK3β inhibitors or by ectopic expression of a dominant-negative mutant of GSK3β but reinforced in cells expressing the constitutively active mutant of GSK3β. Mechanistically, GSK3β suppressed, whereas inhibiting GSK3β facilitated, the activity of cAMP response element-binding protein (CREB), which competes for CREB-binding protein, a transcriptional coactivator essential for TGF-β1/Smad signaling pathway to drive TECs profibrogenic plasticity. In vivo, in mice with folic acid-induced progressive CKD, targeting of GSK3β in renal tubules via genetic ablation or by microdose lithium mitigated the profibrogenic plasticity of TEC, concomitant with attenuated interstitial fibrosis and tubular atrophy. Collectively, GSK3β is likely a pragmatic therapeutic target for averting profibrogenic plasticity of TECs and improving renal fibrosis.


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