Beneficial effects of Huaiqihuang on hyperglycemia-induced MPC5 podocyte dysfunction through the suppression of mitochondrial dysfunction and endoplasmic reticulum stress

Huaiqihuang (HQH) protects podocytes from high glucose-induced apoptosis and inflammation response by regulating PI3K/AKT/mTOR pathway

Diabetic kidney disease (DKD) is one of the common microvascular complications of diabetes, and there are still lack of effective treatments. Huaiqihuang (HQH) is a kind of traditional Chinese medicine mixed preparation, which is mainly made of Trametes robiniophila Murr, Fructus Lycii, and Polygonatum sibiricumhas. It has been shown to be effective in the treatment of DKD, but the specific mechanism has not been fully elucidated. Our results showed that HQH increased the protein expressions of synaptopodin, podocin, WT-1, and Bcl-2, decreased the protein expressions of Bax and cleaved-casepase-3, and activated the NF-ĸB and PI3K/AKT/mTOR pathway in MPC5 cells exposed to high-glucose (HG). Real-time PCR results showed that HQH reduced the mRNA expression of TNF-α, IL-1β, MCP-1, and IL-6. In conclusion, our results showed that HQH may attenuate podocyte injury by inhibiting MPC5 cell apoptosis induced by HG and NF-κB-mediated inflammation response through activation of the PI3K/AKT/mTOR pathway.

Epigenetics and endoplasmic reticulum in podocytopathy during diabetic nephropathy progression

Proteinuria or nephrotic syndrome are symptoms of podocytopathies, kidney diseases caused by direct or indirect podocyte damage. Human health worldwide is threatened by diabetic nephropathy (DN), the leading cause of end-stage renal disease (ESRD) in the world. DN development and progression are largely dependent on inflammation. The effects of podocyte damage on metabolic disease and inflammatory disorders have been documented. Epigenetic and endoplasmic reticulum (ER) stress are also evident in DN. Targeting inflammation pathway and ER stress in podocytes may be a prospective therapy to prevent the progression of DN. Here, we review the mechanism of epigenetics and ER stress on podocyte inflammation and apoptosis, and discuss the potential amelioration of podocytopathies by regulating epigenetics and ER stress as well as by targeting inflammatory signaling, which provides a theoretical basis for drug development to ameliorate DN.

A critical role of the podocyte cytoskeleton in the pathogenesis of glomerular proteinuria and autoimmune podocytopathies

Selective glomerular filtration relies on the membrane separating the glomerular arterioles from the Bowman space. As a major component of the glomerular filtration barrier, podocytes form foot processes by the actin cytoskeleton, which dynamically adjusts in response to environmental changes to maintain filtration barrier integrity. The slit diaphragms bridge the filtration slits between neighboring foot processes and act as signaling hubs interacting with the actin cytoskeleton. Focal adhesions relay signals to regulate actin dynamics while allowing podocyte adherence to the basement membrane. Mutations in actin regulatory and signaling proteins may disrupt the actin cytoskeleton, resulting in foot process retraction, effacement, and proteinuria. Large-scale gene expression profiling platforms, transgenic animal models, and other in vivo gene delivery methods now enhance our understanding of the interactions among podocyte focal adhesions, slit diaphragms, and actin dynamics. In addition, our team found that at least 66% of idiopathic nephrotic syndrome (INS) children have podocyte autoantibodies, which was defined as a new disease subgroup-, autoimmune podocytopathies. This review outlines the pathophysiological mechanisms of podocyte cytoskeleton protein interactions in proteinuria and glomerular podocytopathy.

Mitochondrial Oxidative Stress and Cell Death in Podocytopathies

Podocytopathies are kidney diseases that are driven by podocyte injury with proteinuria and proteinuria-related symptoms as the main clinical presentations. Albeit podocytopathies are the major contributors to end-stage kidney disease, the underlying molecular mechanisms of podocyte injury remain to be elucidated. Mitochondrial oxidative stress is associated with kidney diseases, and increasing evidence suggests that oxidative stress plays a vital role in the pathogenesis of podocytopathies. Accumulating evidence has placed mitochondrial oxidative stress in the focus of cell death research. Excessive generated reactive oxygen species over antioxidant defense under pathological conditions lead to oxidative damage to cellular components and regulate cell death in the podocyte. Conversely, exogenous antioxidants can protect podocyte from cell death. This review provides an overview of the role of mitochondrial oxidative stress in podocytopathies and discusses its role in the cell death of the podocyte, aiming to identify the novel targets to improve the treatment of patients with podocytopathies.

Recent Advances in Traditional Chinese Medicine for Treatment of Podocyte Injury

Podocyte is also called glomerular epithelial cell, which has been considered as the final gatekeeper of glomerular filtration barrier (GFB). As a major contributor to proteinuria, podocyte injury underlies a variety of glomerular diseases and becomes the challenge to patients and their families in general. At present, the therapeutic methods of podocyte injury mainly include angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, steroid and immunosuppressive medications. Nevertheless, the higher cost and side effects seriously disturb patients with podocyte injury. Promisingly, traditional Chinese medicine (TCM) has received an increasing amount of attention from different countries in the treatment of podocyte injury by invigorating spleen and kidney, clearing heat and eliminating dampness, as well enriching qi and activating blood. Therefore, we searched articles published in peer-reviewed English-language journals through Google Scholar, PubMed, Web of Science, and Science Direct. The protective effects of active ingredients, herbs, compound prescriptions, acupuncture and moxibustion for treatment of podocyte injury were further summarized and analyzed. Meanwhile, we discussed feasible directions for future development, and analyzed existing deficiencies and shortcomings of TCM in the treatment of podocyte injury. In conclusion, this paper shows that TCM treatments can serve as promising auxiliary therapeutic methods for the treatment of podocyte injury.

Huaiqihuang (HQH) granule alleviates cyclophosphamide-induced nephrotoxicity via suppressing the MAPK/NF-κB pathway and NLRP3 inflammasome activation

CONTEXT

Severe nephrotoxicity greatly limits the clinical use of the common effective chemotherapeutic agent cyclophosphamide (CYP). Huaiqihuang (HQH) is a Chinese herbal complex with various pharmacological activities, widely used for treating kidney disease.

OBJECTIVE

This study estimates the protective effect of HQH against CYP-induced nephrotoxicity in rats.

MATERIALS AND METHODS

Four groups of 10 Sprague-Dawley rats were pre-treated with once-daily oral gavage of 3 and 6 mg/kg HQH for 5 days before receiving a single dose of CYP (200 mg/kg i.p.) on the 5th day; the control group received equivalent dose of saline. Renal function indices, morphological changes, oxidative stress, apoptosis and inflammatory mediators were measured. In addition, phosphorylation of the NF-κB/MAPK pathway and the activation of the NLRP3 inflammasome were analysed.

RESULTS

Both doses of HQH reduced the levels of serum creatinine (31.27%, 43.61%), urea nitrogen (22.66%, 32.27%) and urine protein (12.87%, 15.98%) in the CYP-treated rats, and improved histopathological aberrations. Additionally, HQH decreased the production of MDA (37.02%, 46.18%) and increased the activities of antioxidant enzyme CAT (59.18%, 112.25%) and SOD (67.10%, 308.34%) after CYP treatment. HQH protected against CYP-induced nephrotoxicity by modulating apoptosis-related protein and suppressing the inflammatory responses. Furthermore, the phosphorylation of the NF-κB/MAPK pathway and the activation of the NLRP3 inflammasome were significantly boosted in CYP-treated rats, which was also abrogated by HQH treatment.

CONCLUSIONS

HQH effectively protected against CYP-induced nephrotoxicity, which was associated with regulating oxidative stress, apoptosis and inflammation, and so HQH may be a useful agent for treating nephrotoxicity caused by CYP.

A Review of Traditional Chinese Medicine in Treating Renal Interstitial Fibrosis via Endoplasmic Reticulum Stress-Mediated Apoptosis

Renal interstitial fibrosis (RIF) is the main pathological manifestation of end-stage renal disease. Recent studies have shown that endoplasmic reticulum (ER) stress is involved in the pathogenesis and development of RIF. Traditional Chinese medicine (TCM), as an effective treatment for kidney diseases, can improve kidney damage by affecting the apoptotic signaling pathway mediated by ER stress. This article reviews the apoptotic pathways mediated by ER stress, including the three major signaling pathways of unfolded protein response, the main functions of the transcription factor C/EBP homologous protein. We also present current research on TCM treatment of RIF, focusing on medicines that regulate ER stress. A new understanding of using TCM to treat kidney disease by regulating ER stress will promote clinical application of Chinese medicine and discovery of new drugs for the treatment of RIF.

Huaier Extract Attenuates Acute Kidney Injury to Chronic Kidney Disease Transition by Inhibiting Endoplasmic Reticulum Stress and Apoptosis via miR-1271 Upregulation

Endoplasmic reticulum stress (ERS) is strongly associated with acute kidney injury (AKI) to chronic kidney disease (CKD) transition. Huaier extract (HE) protects against kidney injury; albeit, the underlying mechanism is unknown. We hypothesized that HE reduces kidney injury by inhibiting ERS. In this study, using an AKI-CKD mouse model of ischemia-reperfusion injury (IRI), we evaluated the effect of HE on AKI-CKD transition. We also explored the underlying molecular mechanisms in this animal model and in the HK-2 human kidney cell line. The results showed that HE treatment improved the renal function, demonstrated by a significant decrease in serum creatinine levels after IRI. HE appreciably reduced the degree of kidney injury and fibrosis and restored the expression of the microRNA miR-1271 after IRI. Furthermore, HE reduced the expression of ERS markers glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) and inhibited apoptosis in the IRI group. This in vivo effect was supported by in vitro results in which HE inhibited apoptosis and decreased the expression of CHOP and GRP78 induced by ERS. We demonstrated that CHOP is a target of miR-1271. In conclusion, HE reduces kidney injury, probably by inhibiting apoptosis and decreasing the expression of GRP78 and CHOP via miR-1271 upregulation.

The Effect of Chinese Traditional Medicine Huaiqihuang (HQH) on the Protection of Nephropathy

Kidney disease is one of the common diseases with high morbidity and high mortality, which brings a huge burden to the society and the patient's family. The pathogenesis, treatment, and prognosis of kidney diseases are related to oxidative stress, inflammation, mitochondrial damage, and immune dysfunction. However, existing treatments always cause some damage to the kidneys. Kidney disease and immunosuppressant used together often lead to drug toxicity, patients with weakened immunity, organic rupture of the normal structure of the kidney, damage to the physiological function of the kidney, etc. Huaiqihuang is a kind of traditional Chinese medicine with a history of more than one thousand years. According to research, Robinia pseudoacacia can regulate the immune function by regulating oxidative stress, calcium inflow, and mitochondrial ATP. At the same time, it is also involved in regulating the ways of cell death, such as apoptosis, autophagy, ferroptosis, pyroptosis, and clockophagy, to reduce kidney damage, which has important clinical value. This article reviews the exact mechanism and clinical application of Huaiqihuang in different types of nephropathy. The aim is to provide new ideas for the treatment of clinical nephropathy.