Hypertension exaggerates renovascular resistance via miR-122-associated stress response in aging

MicroRNAs (miRNAs) role in hypertension: pathogenesis and promising therapeutics

Background

MicroRNAs (miRNAs) are small, non-coding RNA molecules that play a crucial role in regulating various cellular processes, including cell proliferation, differentiation, apoptosis, and disease development. Recent studies have highlighted the importance of miRNAs in the development and progression of essential hypertension, a common form of high blood pressure that affects millions of individuals worldwide. The molecular mechanisms by which miRNAs regulate hypertension are complex and multifaceted. MiRNAs target the 3' untranslated regions of mRNA molecules, thereby regulating the synthesis of specific proteins involved in cardiovascular function. For instance, miRNAs are known to regulate the expression of genes involved in blood vessel tone, cardiac function, and inflammation. The growing body of research on miRNAs in hypertension has highlighted their potential as therapeutic targets for managing this condition. Studies have shown that miRNA-based therapies can modulate the expression of key genes involved in hypertension, leading to improvements in blood pressure and cardiovascular function. However, more research is needed to fully understand the mechanisms of miRNA-mediated hypertension and to develop effective therapeutic strategies.

Conclusions

In summary, this review highlights the current understanding of the role of miRNAs in essential hypertension, including their molecular mechanisms and potential therapeutic applications. Further research is needed to fully understand the impact of miRNAs on hypertension and to develop new treatments for this common and debilitating condition.

MiR-155-5p Attenuates Vascular Smooth Muscle Cell Oxidative Stress and Migration via Inhibiting BACH1 Expression

The malfunction of vascular smooth muscle cells (VSMCs) is an initiating factor in the pathogenesis of pathological vascular remodeling, including hypertension-related vascular lesions. MicroRNAs (miRNAs) have been implicated in the pathogenesis of VSMC proliferation and migration in numerous cases of cardiovascular remodeling. The evidence for the regulatory role of miR-155-5p in the development of the cardiovascular system has been emerging. However, it was previously unclear whether miR-155-5p participated in the migration of VSMCs under hypertensive conditions. Thus, we aimed to define the exact role and action of miR-155-5p in VSMC migration by hypertension. Here, we detected that the level of miR-155-5p was lower in primary VSMCs from spontaneously hypertensive rats (SHRs). Its overexpression attenuated, while its depletion accelerated, the migration and oxidative damage of VSMCs from SHRs. Our dual-luciferase reporter assay showed that miRNA-155-5p directly targeted the 3'-untranslated region (3'-UTR) of BTB and CNC homology 1 (BACH1). The miR-155-5p mimic inhibited BACH1 upregulation in SHR VSMCs. By contrast, the deletion of miR-155-5p further elevated the upregulation of BACH1 in SHR-derived VSMCs. Importantly, the overexpression of miR-155-5p and knockdown of BACH1 had synergistic effects on the inhibition of VSMCs in hypertension. Collectively, miR-155-5p attenuates VSMC migration and ameliorates vascular remodeling in SHRs, via suppressing BACH1 expression.

Sex- and age-related differences in renal and cardiac injury and senescence in stroke-prone spontaneously hypertensive rats

BACKGROUND

Sex differences play a critical role in the incidence and severity of cardiovascular diseases, whereby men are at a higher risk of developing cardiovascular disease compared to age-matched premenopausal women. Marked sex differences at the cellular and tissue level may contribute to susceptibility to cardiovascular disease and end-organ damage. In this study, we have performed an in-depth histological analysis of sex differences in hypertensive cardiac and renal injury in middle-aged stroke-prone spontaneously hypertensive rats (SHRSPs) to determine the interaction between age, sex and cell senescence.

METHODS

Kidneys, hearts and urine samples were collected from 6.5- and 8-month-old (Mo) male and female SHRSPs. Urine samples were assayed for albumin and creatinine content. Kidneys and hearts were screened for a suite of cellular senescence markers (senescence-associated β-galactosidase, p16^INK4a, p21, γH2AX). Renal and cardiac fibrosis was quantified using Masson's trichrome staining, and glomerular hypertrophy and sclerosis were quantified using Periodic acid-Schiff staining.

RESULTS

Marked renal and cardiac fibrosis, concomitant with albuminuria, were evident in all SHRSPs. These sequelae were differentially affected by age, sex and organ. That is, the level of fibrosis was greater in the kidney than the heart, males had greater levels of fibrosis than females in both the heart and kidney, and even a 6-week increase in age resulted in greater levels of kidney fibrosis in males. The differences in kidney fibrosis were reflected by elevated levels of cellular senescence in the kidney in males but not females. Senescent cell burden was significantly less in cardiac tissue compared to renal tissue and was not affected by age or sex.

CONCLUSIONS

Our study demonstrates a clear sex pattern in age-related progression of renal and cardiac fibrosis and cellular senescence in SHRSP rats. A 6-week time frame was associated with increased indices of cardiac and renal fibrosis and cellular senescence in male SHRSPs. Female SHRSP rats were protected from renal and cardiac damage compared to age-matched males. Thus, the SHRSP is an ideal model to investigate the effects of sex and aging on organ injury over a short timeframe.

Roles of extracellular vesicles in ageing-related chronic kidney disease: demon or angel

Ageing is a universal and unavoidable phenomenon that significantly increases the risk of developing chronic kidney disease (CKD). It has been reported that ageing is associated with functional disruption and structural damage to the kidneys. Extracellular vesicles (EVs), which are nanoscale membranous vesicles containing lipids, proteins, and nucleic acids, are secreted by cells into the extracellular spaces. They have diverse functions such as repairing and regenerating different forms of ageing-related CKD and playing a crucial role in intercellular communication. This paper reviews the etiology of ageing in CKD, with particular attention paid to the roles of EVs as carriers of ageing signals and anti-ageing therapeutic strategies in CKD. In this regard, the double-edged role of EVs in ageing-related CKD is examined, along with the potential for their application in clinical settings.

Noncoding RNAs in age-related cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality in the adult population worldwide and represent a severe economic burden and public health concern. The majority of human genes do not code for proteins. However, noncoding transcripts play important roles in ageing that significantly increases the risk for CVDs. Noncoding RNAs (ncRNAs) are critical regulators of multiple biological processes related to ageing such as oxidative stress, mitochondrial dysfunction and chronic inflammation. NcRNAs are also involved in pathophysiological developments within the cardiovascular system including arrhythmias, cardiac hypertrophy, fibrosis, myocardial infarction and heart failure. In this review article, we cover the roles of ncRNAs in cardiovascular ageing and disease as well as their potential therapeutic applications in CVDs.

MicroRNA-122-5p Aggravates Angiotensin II-Mediated Myocardial Fibrosis and Dysfunction in Hypertensive Rats by Regulating the Elabela/Apelin-APJ and ACE2-GDF15-Porimin Signaling

Hypertension is the leading risk factor for cardiovascular disorders. This study aimed to explore roles of microRNA (miR)-122-5p in hypertension. Angiotensin II (Ang II; 1.5 mg/kg/day) with an osmotic minipump was used to induce hypertensive rats pretreated by rAAV-miR-122-5p or rAAV-GFP, respectively. Notably, Ang II infusion caused marked increases in myocardial fibrosis, inflammation, oncosis, and oxidant injury in rats, which were aggravated by rAAV-miR-122-5p. RAAV-miR-122-5p exacerbated Ang II–mediated cardiac dysfunction and structural injury in hypertensive rats, with downregulated levels of apelin, elabela, ACE2, and GDF15, as well as upregulated expression of porimin and CTGF. In cultured rat cardiac fibroblasts, Ang II contributed to augmentation of cellular oncosis, migration, inflammation, and oxidative stress, with reduction of apelin, elabela, ACE2, and GDF15 levels, which were rescued by miR-122 inhibitor. In summary, miR-122-5p exacerbates myocardial fibrosis and dysfunction in hypertensive rats by modulating the elabela/apelin-ACE2-GDF15 signaling. MiR-122-5p has potential therapeutic significance for hypertension and hypertensive cardiac injury.

MicroRNA-122-5p promotes renal fibrosis and injury in spontaneously hypertensive rats by targeting FOXO3

Hypertensive renal injury is accompanied by tubular interstitial fibrosis leading to increased risk for renal failure. This study aimed to explore the influences of miR-122-5p in hypertension-mediated renal fibrosis and damage. 14-week-old male SHR and WKY rats were randomly assigned to treat with rAAV-miR-122-5p or rAAV-GFP for 8 weeks. There were marked increases in miR-122-5p and Kim-1 levels and decreases in FOXO3 and SIRT6 levels in hypertensive rats. Transfection with rAAV-miR-122-5p triggered exacerbation of renal fibrosis, apoptosis and inflammatory injury in SHR, associated with downregulated levels of FOXO3, SIRT6, ATG5 and BNIP3 as well as upregulated expression of Kim-1, NOX4, CTGF, and TGF-β1. In cultured primary mouse renal tubular interstitial fibroblasts, exposure to angiotensin II resulted in obvious downregulation of FOXO3, SIRT6, ATG5, BNIP3 and nitric oxide levels as well as augmented cellular migration, oxidative stress, and inflammation, which were exacerbated by miR-122-5p mimic while rescued by miR-122-5p inhibitor and rhFOXO3, respectively. Notably, knockdown of FOXO3 strikingly blunted cellular protective effects of miR-122-5p inhibitor. In summary, miR-122-5p augments renal fibrosis, inflammatory and oxidant injury in hypertensive rats by suppressing the expression of FOXO3. Pharmacological inhibition of miR-122-5p has potential therapeutic significance for hypertensive renal injury and fibrosis-related kidney diseases.

Lipid Disorders in NAFLD and Chronic Kidney Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver dysfunction and is characterized by exaggerated lipid accumulation, inflammation and even fibrosis. It has been shown that NAFLD increases the risk of other chronic diseases, particularly chronic kidney disease (CKD). Lipid in excess could lead to liver and kidney lesions and even end-stage disease through diverse pathways. Dysregulation of lipid uptake, oxidation or de novo lipogenesis contributes to the toxic effects of ectopic lipids which promotes the development and progression of NAFLD and CKD via triggering oxidative stress, apoptosis, pro-inflammatory and profibrotic responses. Importantly, dyslipidemia and release of pro-inflammatory cytokines caused by NAFLD (specifically, nonalcoholic steatohepatitis) are considered to play important roles in the pathological progression of CKD. Growing evidence of similarities between the pathogenic mechanisms of NAFLD and those of CKD has attracted attention and urged researchers to discover their common therapeutic targets. Here, we summarize the current understanding of molecular aberrations underlying the lipid metabolism of NAFLD and CKD and clinical evidence that suggests the relevance of these pathways in humans. This review also highlights the orchestrated inter-organ cross-talk in lipid disorders, as well as therapeutic options and opportunities to counteract NAFLD and CKD.

Sirt6-mediated Nrf2/HO-1 activation alleviates angiotensin II-induced DNA DSBs and apoptosis in podocytes

Recent studies suggested that DNA double-strand breaks (DSBs) were associated with the pathogenesis of chronic kidney disease (CKD). The purpose of this investigation was to determine the role of Sirtuin6 (Sirt6), a histone deacetylase related to DNA damage repair, in angiotensin (Ang) II-induced DNA DSBs and the cell injury of podocytes and explore the possible mechanism. Here we showed that an increase of DNA DSBs was accompanied by a reduction in Sirt6 expression in the glomeruli of patients with hypertensive nephropathy (HN). Similar results were found in rat kidneys infused with Ang II and in cultured podocytes stimulated with Ang II. Sirt6 overexpression inhibited Ang II-induced ROS generation and DNA DSBs, and thus served as a protection against Ang II-induced apoptosis in podocytes. Moreover, Sirt6 activation enhanced Nrf2 and HO-1 gene expressions in podocytes after Ang II treatment. Furthermore, Nrf2 knockdown could partly reverse the cytoprotective effects of Sirt6 activation. In conclusion, our observations demonstrated that the Sirt6-Nrf2-HO-1 pathway played a vital role in relieving Ang II-mediated oxidative DNA damage and podocyte injury.

Roles of MicroRNA-122 in Cardiovascular Fibrosis and Related Diseases

Fibrotic diseases cause annually more than 800,000 deaths worldwide, where of the majority accounts for cardiovascular fibrosis, which is characterized by endothelial dysfunction, myocardial stiffening and reduced dispensability. MicroRNAs (miRs), small noncoding RNAs, play critical roles in cardiovascular dysfunction and related disorders. Intriguingly, there is a critical link among miR-122, cardiovascular fibrosis, sirtuin 6 (SIRT6) and angiotensin-converting enzyme 2 (ACE2), which was recently identified as a coreceptor for SARS-CoV2 and a negative regulator of the rennin-angiotensin system. MiR-122 overexpression appears to exacerbate the angiotensin II-mediated loss of autophagy and increased inflammation, apoptosis, extracellular matrix deposition, cardiovascular fibrosis and dysfunction by modulating the SIRT6-Elabela-ACE2, LGR4-β-catenin, TGFβ-CTGF and PTEN-PI3K-Akt signaling pathways. More importantly, the inhibition of miR-122 has proautophagic, antioxidant, anti-inflammatory, anti-apoptotic and antifibrotic effects. Clinical and experimental studies clearly demonstrate that miR-122 functions as a crucial hallmark of fibrogenesis, cardiovascular injury and dysfunction. Additionally, the miR-122 level is related to the severity of hypertension, atherosclerosis, atrial fibrillation, acute myocardial infarction and heart failure, and miR-122 expression is a risk factor for these diseases. The miR-122 level has emerged as an early-warning biomarker cardiovascular fibrosis, and targeting miR-122 is a novel therapeutic approach against progression of cardiovascular dysfunction. Therefore, an increased understanding of the cardiovascular roles of miR-122 will help the development of effective interventions. This review summarizes the biogenesis of miR-122; regulatory effects and underlying mechanisms of miR-122 on cardiovascular fibrosis and related diseases; and its function as a potential specific biomarker for cardiovascular dysfunction.

Cholesterol impairs hepatocyte lysosomal function causing M1 polarization of macrophages via exosomal miR-122-5p

Nonalcoholic steatohepatitis (NASH) is a major threat to health worldwide. Lipotoxicity and macrophage-mediated inflammation play key roles in the pathogenesis of NASH. In this study, we found that individuals with higher serum LDL-C levels have a higher prevalence of nonalcoholic fatty liver disease (NAFLD) and elevated levels of glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase and alkaline phosphatase. A logistic regression analysis revealed that serum LDL-C level is an independent risk factor for the prevalence and prognosis of NAFLD. In vitro, we used ox-LDL and MβCD-cholesterol to treat Huh7 cells and found that cholesterol loading reduced lysosomal quantity and impaired lysosomal acidification, reducing the number of multivesicular bodies (MVBs) colocalizing with lysosomes. The bafilomycin A1 inhibition of lysosomal function also inhibited lysosomal MVBs degradation, promoting the release of exosomes from the Huh7 cells. Next, we found that cholesterol loading promoted exosome release from the Huh7 cells. The exosomes from the cholesterol-loaded cells increased the ratio of the THP-1 cells positive for the M1 marker (iNOS-1) without affecting the ratio of the cells positive for the M2 marker (CD206). Moreover, an elevated level of miR-122-5p was observed in exosomes derived from the Huh7 cells loaded with cholesterol. While the miR-122-5p mimics promoted THP-1 M1 polarization, downregulating miR-122-5p in the Huh7 cells inhibited the exosome-induced activation of macrophages and macrophage-related inflammation. These findings suggest that cholesterol plays an important role in the development and progression of NASH. Cholesterol-induced lysosomal dysfunction increases exosome release from hepatocytes, resulting in M1 polarization and macrophage-induced inflammation in a miR-122-5p-dependent manner.

COMPREHENSIVE EXPRESSION ANALYSIS OF MIRNAS IN MICE EXPOSED TO LETHAL RADIATION AND/OR RADIO-MITIGATIVE DRUG

New minimally invasive indicators that are capable of predicting the biological effects and radiation damage to various organs and systems are urgently needed for the development of optimal treatment protocols for victims of radiation accidents. In the present study, we focused on microRNA (miRNA) that have recently emerged as biomarkers for predicting and diagnosing various pathological conditions and identified the serum miRNA signatures. All of the mice treated with lethal radiation alone strongly expressed certain serum miRNAs detectable for 24 h after radiation exposure, whereas the administration of radio-mitigative drug immediately after irradiation suppressed these miRNA expressions to the same levels as in control mice. These results suggest that serum miRNAs may reflect the degree of radiation damage and can be used to predict the radiation-mitigative information in victims of accidental radiation exposure.

Novel Contributors and Mechanisms of Cellular Senescence in Hypertension-Associated Premature Vascular Aging

Hypertension has been described as a condition of premature vascular aging, relative to actual chronological age. In fact, many factors that contribute to the deterioration of vascular function as we age are accelerated in hypertension. Nonetheless, the precise mechanisms that underlie the aged phenotype of arteries from hypertensive patients and animals remain elusive. Cellular senescence is an age-related physiologic process in which cells undergo irreversible growth arrest. Although controlled senescence negatively regulates cell proliferation and promotes tissue regeneration, uncontrolled senescence can contribute to disease pathogenesis by presenting the senescence-associated secretory phenotype, in which molecules such as proinflammatory cytokines, matrix metalloproteases, and reactive oxygen species are released into tissue microenvironments. This review will address and critically evaluate the current literature on the role of cellular senescence in hypertension, with particular emphasis on cells types that mediate and modulate vascular function and structure.