Rotenone Attenuates Renal Injury in Aldosterone-Infused Rats by Inhibiting Oxidative Stress, Mitochondrial Dysfunction, and Inflammasome Activation

Rotenone activates the LKB1-AMPK-ULK1 signaling pathway to induce autophagy and apoptosis in rat thoracic aortic endothelial cells

BACKGROUND

The specific mechanism by which rotenone impacts thoracic aortic autophagy and apoptosis is unknown. We aimed to investigate the regulatory effects of rotenone on autophagy and apoptosis in rat thoracic aortic endothelial cells (RTAEC) via activation of the LKB1-AMPK-ULK1 signaling pathway and to elucidate the molecular mechanisms of rotenone on autophagy and apoptosis in vascular endothelial cells.

METHODS

In vivo, 60 male SD rats were randomly selected and divided into 5 groups: control (Con), DMSO, 1, 2, and 4 mg/kg groups, respectively. After 28 days of treatment, histopathological and ultrastructural changes in each group were observed using HE and transmission electron microscopy; Autophagy, apoptosis, and LKB1-AMPK-ULK1 pathway-related proteins were detected by Western blot; Apoptosis levels in the thoracic aorta were detected by TUNEL. In vitro, RTAEC were cultured and divided into control (Con), DMSO, 20, 100, 500, and 1000 nM groups. After 24 h of intervention, autophagy, apoptosis, and LKB1-AMPK-ULK1 pathway-related factors were detected by Western blot and qRT-PCR; Flow cytometry to detect apoptosis levels; Autophagy was inhibited with 3-MA and CQ to detect apoptosis levels, and changes in autophagy, apoptosis, and downstream factors were detected by the AMPK inhibitor CC intervention.

RESULTS

Gavage in SD rats for 28 days, some degree of damage was observed in the thoracic aorta and heart of the rotenone group, as well as the appearance of autophagic vesicles was observed in the thoracic aorta. TUNEL analysis revealed higher apoptosis in the rotenone group's thoracic aorta; RTAEC cultured in vitro, after 24 h of rotenone intervention, showed increased ROS production and significantly decreased ATP production. The flow cytometry data suggested an increase in the number of apoptotic RTAEC. The thoracic aorta and RTAEC in the rotenone group displayed elevated levels of autophagy and apoptosis, and the LKB1-AMPK-ULK1 pathway proteins were activated and expressed at higher levels. Apoptosis and autophagy were both suppressed by the autophagy inhibitors 3-MA and CQ. The AMPK inhibitor CC reduced autophagy and apoptosis in RTAEC and suppressed the production of the AMPK downstream factors ULK1 and P-ULK1.

CONCLUSIONS

Rotenone may promote autophagy in the thoracic aorta and RTAEC by activating the LKB1-AMPK-ULK1 signaling pathway, thereby inducing apoptosis.

Protective effect of natural products in the metabolic-associated kidney diseases via regulating mitochondrial dysfunction

Metabolic syndrome (MS) is a complex group of metabolic disorders syndrome with hypertension, hyperuricemia and disorders of glucose or lipid metabolism. As an important organ involved in metabolism, the kidney is inevitably attacked by various metabolic disorders, leading to abnormalities in kidney structure and function. Recently, an increasing number of studies have shown that mitochondrial dysfunction is actively involved in the development of metabolic-associated kidney diseases. Mitochondrial dysfunction can be used as a potential therapeutic strategy for the treatment of metabolic-associated kidney diseases. Many natural products have been widely used to improve the treatment of metabolic-associated kidney diseases by inhibiting mitochondrial dysfunction. In this paper, by searching several authoritative databases such as PubMed, Web of Science, Wiley Online Library, and Springer Link. We summarize the Natural Products Protect Against Metabolic-Associated Kidney Diseases by Regulating Mitochondrial Dysfunction. In this review, we sought to provide an overview of the mechanisms by which mitochondrial dysfunction impaired metabolic-associated kidney diseases, with particular attention to the role of mitochondrial dysfunction in diabetic nephropathy, gouty nephropathy, hypertensive kidney disease, and obesity-related nephropathy, and then the protective role of natural products in the kidney through inhibition of mitochondrial disorders, thus providing a systematic understanding of the targets of mitochondrial dysfunction in metabolic-associated kidney diseases, and finally a review of promising therapeutic targets and herbal candidates for metabolic-associated kidney diseases through inhibition of mitochondrial dysfunction.

NUCB2: roles in physiology and pathology

Nucleobindin2 (NUCB2) is a member of nucleobindin family which was first found in the nucleus of the hypothalamus, and had a relationship in diet and energy homeostasis. Its location in normal tissues such as stomach and islet further confirms that it plays a vital role in the regulation of physiological functions of the body. Besides, NUCB2 participates in tumorigenesis through activating various signal-pathways, more and more studies indicate that NUCB2 might impact tumor progression by promoting or inhibiting proliferation, apoptosis, autophagy, metastasis, and invasion of tumor cells. In this review, we comprehensively stated NUCB2's expression and functions, and introduced the role of NUCB2 in physiology and pathology and its mechanism. What is more, pointed out the potential direction of future research.

Involvement of Inflammasome Components in Kidney Disease

Inflammasomes are multiprotein complexes with an important role in the innate immune response. Canonical activation of inflammasomes results in caspase-1 activation and maturation of cytokines interleukin-1β and -18. These cytokines can elicit their effects through receptor activation, both locally within a certain tissue and systemically. Animal models of kidney diseases have shown inflammasome involvement in inflammation, pyroptosis and fibrosis. In particular, the inflammasome component nucleotide-binding domain-like receptor family pyrin domain containing 3 (NLRP3) and related canonical mechanisms have been investigated. However, it has become increasingly clear that other inflammasome components are also of importance in kidney disease. Moreover, it is becoming obvious that the range of molecular interaction partners of inflammasome components in kidney diseases is wide. This review provides insights into these current areas of research, with special emphasis on the interaction of inflammasome components and redox signalling, endoplasmic reticulum stress, and mitochondrial function. We present our findings separately for acute kidney injury and chronic kidney disease. As we strictly divided the results into preclinical and clinical data, this review enables comparison of results from those complementary research specialities. However, it also reveals that knowledge gaps exist, especially in clinical acute kidney injury inflammasome research. Furthermore, patient comorbidities and treatments seem important drivers of inflammasome component alterations in human kidney disease.

Environmental neurotoxicants and inflammasome activation in Parkinson's disease - A focus on the gut-brain axis

Inflammasomes are multi-protein complexes expressed in immune cells that function as intracellular sensors of environmental, metabolic and cellular stress. Inflammasome activation in the brain, has been shown to drive neuropathology and disease progression by multiple mechanisms, making it one of the most attractive therapeutic targets for disease modification in Parkinson's Disease (PD). Extensive inflammasome activation is evident in the brains of people with PD at the sites of dopaminergic degeneration and synuclein aggregation. While substantial progress has been made on validating inflammasome activation as a therapeutic target for PD, the mechanisms by which inflammasome activation is triggered and sustained over the disease course remain poorly understood. A growing body of evidence point to environmental and occupational chemical exposures as possible triggers of inflammasome activation in PD. The involvement of the gastrointestinal system and gut microbiota in PD pathophysiology is beginning to be elucidated, especially the profound link between gut dysbiosis and immune activation. While large cohort studies confirmed specific changes in the gut microbiota in PD patients compared to age-matched healthy controls, recent research suggest that synuclein pathology could be initiated in the gastrointestinal tract. In this review, we present a summarized perspective on current understanding on inflammasome activation and the gut-brain-axis link during PD pathophysiology. We discuss multiple environmental toxicants that are implicated as the etiological agents in causing idiopathic PD and their mechanistic underpinnings during neuroinflammatory events. We additionally present future directions that needs to address the research questions related to the gut-microbiome-brain mechanisms in PD.

Berberine Reduces Renal Cell Pyroptosis in Golden Hamsters with Diabetic Nephropathy through the Nrf2-NLRP3-Caspase-1-GSDMD Pathway

Objective. To observe the effect of berberine (BBR) on kidney cell pyroptosis in golden hamsters with diabetic nephropathy (DN) and to explore the molecular mechanism of its renal protection. Methods. Fifty clean-grade male golden hamsters were randomly divided into a control group (10) and a model building group (40). The DN model was established by high-sugar and high-fat feeding and injection of a small amount of STZ. After successful establishment of the model, they were randomly divided into a model group, western medicine group, and berberine high- and low-dose groups. The western medicine group was given irbesartan 13.5 mg/kg, and the berberine high- and low-dose groups were given BBR 200 mg/kg and 100 mg/kg, respectively, for 8 consecutive weeks. An automatic biochemical analyser was used to measure blood glucose, blood lipids, kidney function, MDA, and other indicators; radioimmunoassay was used to assess serum insulin; enzyme-linked immunosorbent assay (ELISA) was used to quantify IL-1β, IL-6, IL-18, TNF-α; HE, PAS, and Masson staining were used to observe kidney pathological tissue morphology; western blot and real-time fluorescent quantitative PCR were used to assess protein and mRNA expression of molecules, such as Nrf2, NLRP3, Caspase-1, and GSDMD; and TUNEL staining was used to detect DNA damage. SPSS statistical software was used for the data analysis. Results. The kidney tissues of golden hamsters in the control group were normal; Nrf2 was highly expressed, serum MDA level was low, NLRP3 expression in kidney tissue was not obvious, Caspase-1 and GSDMD were weakly expressed, and only a few TUNEL-positive cells were observed. Compared with the control group, the golden hamsters in the model group had obvious renal pathological damage; blood glucose, blood lipids, renal function-related indexes, insulin, and inflammatory factors IL-1β, IL-6, IL-18, and TNF-α were increased ( $P<0.05$ ); NLRP3, Caspase-1, and GSDMD expression was increased; Nrf2 expression was decreased; MDA level was increased ( $P<0.05$ ); and the number of TUNEL-positive cells was increased. Compared with the model group, the pathological morphology of the kidney tissue of golden hamsters in the three treatment groups was significantly improved; blood glucose, blood lipids, renal function, and the expression of inflammatory factors IL-1β and IL-6 were reduced ( $P<0.05$ ); NLRP3, Caspase-1, GSDMD, and other molecular proteins and mRNA expression were decreased; Nrf2 expression was increased; MDA level was decreased ( $P<0.05$ ); and the number of TUNEL-positive cells was decreased. Conclusion. DN golden hamster kidney NLRP3-Caspase-1-GSDMD signalling was enhanced. BBR can reduce oxidative stress damage by regulating antioxidative Nrf2 and then regulating NLRP3-Caspase-1-GSDMD signalling to inhibit pyroptosis, antagonizing DN inflammation-induced damage.

Autophagosome protects proximal tubular cells from aldosterone-induced senescence through improving oxidative stress

Aldosterone exerts an enormous function on proximal tubular cells (PTC) senescence, which is a common pathomechanism contributing to renal dysfunction. Numerous studies have shown that oxidative stress is deeply involved in the pathophysiologic processes of chronic kidney diseases. The study aims to investigate whether autophagy could regulate the process of senescence through oxidative stress in PTC both in vivo and ex vivo. Our results suggested that aldosterone treatment increased the senescence and oxidative stress as evidenced by increased percent of SA-β-Gal positive cells, reactive oxygen species level, expression of NADPH oxidase 4 (NOX4) rather than NOX2, and the up-regulation of p21 in cultured PTC. Furthermore, the alternation of the expression of p62 and LC3-II/LC3-I demonstrated that aldosterone treatment remarkably influenced autophagic flux. NOX4 siRNA treatment or autophagy induction with rapamycin reduced the oxidative stress and senescence in aldosterone-induced PTC. On the contrary, inhibition of autophagy with chloroquine worsened these changes. Similar results were further confirmed in vivo. Our results suggested that autophagy may become a realistic therapeutic strategy against aldosterone-induced PTC injury via improving oxidative stress.

Rotenone and 3-bromopyruvate toxicity impacts electrical and structural cardiac remodeling in rats

3-Bromopyruvate (3-BrPA) is a promising agent that has been widely studied in the treatment of cancer and pulmonary hypertension. Rotenone is a pesticide commonly used on farms and was shown to have anti-cancer activity and delay fibrosis progression in chronic kidney disease in a recent study. However, there are few studies showing the toxicity of rotenone and 3-BrPA in the myocardium. To support further medical exploration, it is necessary to clarify the side effects of these compounds on the heart. This study was designed to examine the cardiotoxicity of 3-BrPA and rotenone by investigating electrical and structural cardiac remodeling in rats. Forty male rats were divided into 4 groups (n = 10 in each group) and injected intraperitoneally with 3-BrPA, rotenone or a combination of 3-BrPA and rotenone. The ventricular effective refractory period (VERP), corrected QT interval (QTc), and ventricular tachycardia/ventricular fibrillation (VT/VF) inducibility were measured. The expression of Cx43, Kir2.1, Kir6.2, DHPRα₁, KCNH2, caspase3, caspase9, Bax, Bcl2, and P53 was detected. Masson's trichrome, TUNEL, HE, and PAS staining and transmission electron microscopy were used to detect pathological and ultrastructural changes. Our results showed that rotenone alone and rotenone combined with 3-BrPA significantly increased the risk of ventricular arrhythmias. Rotenone combined with 3-BrPA caused myocardial apoptosis, and rotenone alone and rotenone combined with 3-BrPA caused electrical and structural cardiac remodeling in rats.

Inhibition of Mitochondrial Complex I Aggravates Folic Acid-Induced Acute Kidney Injury

Background: Some researches revealed that mitochondrial dysfunction is associated with various kidney injury. However, the role of mitochondrial dysfunction in the pathogenesis of acute kidney injury (AKI) still needs evidence. Methods: We evaluated the effect of mitochondrial complex I inhibitor rotenone on folic acid (FA)-induced AKI in mice. Results: Strikingly, the mice pretreated with rotenone at a dose of 200 ppm in food showed exacerbated kidney injury as shown by higher levels of blood urea nitrogen and creatinine compared with FA alone group. Meanwhile, both renal tubular injury score and the expression of renal tubular injury marker neutrophil gelatinase-associated lipocalin were further elevated in rotenone-pretreated mice, suggesting the deteriorated renal tubular injury. Moreover, the decrements of mitochondrial DNA copy number and the expressions of mitochondrial Cytochrome c oxidase subunit 1, mitochondrial NADH dehydrogenase subunit 1, and mitochondria-specific superoxide dismutase (SOD2) in the kidneys of FA-treated mice were further reduced in rotenone-pretreated mice, indicating the aggravated mitochondrial damage. In parallel with the SOD2 reduction, the oxidative stress markers of malondialdehyde and HO-1 displayed greater increment in AKI mice with rotenone pretreatment in line with the deteriorated apoptotic response and inflammation. Conclusion: Our results suggested that the inhibition of mitochondrial complex I activity aggravated renal tubular injury, mitochondrial damage, oxidative stress, cell apoptosis, and inflammation in FA-induced AKI.

Mitochondrial activity contributes to impaired renal metabolic homeostasis and renal pathology in STZ-induced diabetic mice

Diabetic nephropathy (DN) has become the main cause of end-stage renal disease worldwide, but the efficacy of current therapeutic strategies on DN remains unsatisfactory. Recent research has reported the involvement of metabolic rearrangement in the pathological process of DN, and of all the disturbances in metabolism, mitochondria serve as key regulatory hubs. In the present study, high-resolution mass spectrometry-based nontarget metabolomics was used to uncover the metabolic characteristics of the early diabetic kidney with or without the inhibition of mitochondrial activity. At first, we observed a moderate enhancement of mitochondrial complex-1 activity in the diabetic kidney, which was completely normalized by the specific mitochondrial complex-1 inhibitor rotenone (ROT). Meanwhile, metabolomics data indicated an overactivated pentose phosphate pathway, purine and pyrimidine metabolism, hexosamine biosynthetic pathway, and tricarboxylic acid cycle, which were strikingly corrected by ROT. In addition, ROT also strikingly corrected imbalanced redox homeostasis, possibly by increasing the ratio of antioxidant metabolites glutathione and NADPH against their oxidative form. In agreement with the improved metabolic status and oxidative response, ROT attenuated glomerular and tubular injury efficiently. Fibrotic markers (fibronectin, α-smooth muscle actin, collagen type I, and collagen type III), inflammatory factors (TNF-α, IL-1β, and ICAM-1), and oxidative stress were all markedly blocked by ROT. In vitro, ROT dose dependently attenuated high glucose-induced proliferation and extracellular matrix production in mesangial cells. Collectively, these findings revealed that the overactivation of mitochondrial activity in the kidney could contribute to metabolic disorders and the pathogenesis of early DN.

Roles of Inflammasomes in Inflammatory Kidney Diseases

The immune system has a central role in eliminating detrimental factors, by frequently launching inflammatory responses towards pathogen infection and inner danger signal outbreak. Acute and chronic inflammatory responses are critical determinants for consequences of kidney diseases, in which inflammasomes were inevitably involved. Inflammasomes are closely linked to many kidney diseases such as acute kidney injury and chronic kidney diseases. Inflammasomes are macromolecules consisting of multiple proteins, and their formation initiates the cleavage of procaspase-1, resulting in the activation of gasdermin D as well as the maturation and release of interleukin-1β and IL-18, leading to pyroptosis. Here, we discuss the mechanism in which inflammasomes occur, as well as their roles in inflammatory kidney diseases, in order to shed light for discovering new therapeutical targets for the prevention and treatment of inflammatory kidney diseases and consequent end-stage renal disease.

NLRP inflammasome as a key role player in the pathogenesis of environmental toxicants

Exposure to environmental toxicants (ET) results in specific organ damage and auto-immune diseases, mostly mediated by inflammatory responses. The NLRP3 inflammasome has been found to be the major initiator of the associated pathologic inflammation. It has been found that ETs can trigger all the signals required for an NLRP3-mediated response. The exaggerated activation of the NLRP3 inflammasome and its end product IL-1β, is responsible for the pathogenesis caused by many ETs including pesticides, organic pollutants, heavy metals, and crystalline compounds. Therefore, an extensive study of these chemicals and their mechanisms of inflammasome (INF) activation may provide the scientific evidence for possible targeting of this pathway by proposing possible protective agents that have been previously shown to affect INF compartments and its activation. Melatonin and polyunsaturated fatty acids (PUFA) are among the safest and the most studied of these agents, which affect a wide variety of cellular and physiological processes. These molecules have been shown to suppress the NLRP3 inflammasome mostly through the regulation of cellular redox status and the nuclear factor-κB (NF-κB) pathway, rendering them potential promising compounds to overcome ET-mediated organ damage. In the present review, we have made an effort to extensively review the ETs that exert their pathogenesis via the stimulation of inflammation, their precise mechanisms of action and the possible protective agents that could be potentially used to protect against such toxicants.

Inhibition of the mitochondrial complex-1 protects against carbon tetrachloride-induced acute liver injury

Mitochondrial dysfunction has been documented to play a crucial role in the pathogenesis of liver injury. In the present study, we investigated the role of rotenone, a mitochondrial complex-1 inhibitor, in carbon tetrachloride (CCl₄) -induced acute liver injury, as well as the underlying mechanisms. Before CCl₄ administration, the mice were pretreated with rotenone at a dose of 250 ppm in food for three days. Then CCl₄ was administered to the mice for 16 h by intraperitoneal injection. The liver injury, mitochondrial status, oxidative stress, and inflammation were examined. Strikingly, CCl₄ treatment markedly induced liver injury as shown by enhanced serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and morphological lesions (HE stating), which was significantly attenuated by rotenone treatment in line with the reduced activity of mitochondrial complex-1. Meanwhile, oxidative stress markers of malondialdehyde (MDA), 4-hydroxynonenal (HNE), and dihydroethidium (DHE) and the inflammatory markers of IL-1β, MCP-1, TNF-α, TLR-4, and IL-6 were also significantly suppressed by rotenone. More importantly, the mitochondrial abnormalities shown by the reduction of SOD2, mitochondrial transcription factor A (TFAM), mitochondrial NADH dehydrogenase subunit 1 (mtND1), and Cytb were significantly restored, indicating that rotenone protected against mitochondrial damage induced by CCl₄ in liver. Moreover, rotenone treatment alone did not significantly alter liver morphology and liver enzymes ALT and AST. CYP2E1, a metabolic enzyme of CCl₄, was also not significantly affected by rotenone. In conclusion, rotenone protected the liver from CCl₄-induced damage possibly by inhibiting the mitochondrial oxidative stress and inflammation.

Inhibition of mitochondrial complex I by rotenone protects against acetaminophen-induced liver injury

Acetaminophen (APAP) is widely used as an antipyretic analgesic in clinic. However, overdose-related severe liver injury is a major concern of this drug. Recently, accumulating evidence indicated an important role of mitochondrial abnormality in the pathogenesis of APAP hepatoxicity. Thus, the present investigation was undertaken to evaluate the effect of mitochondrial complex I inhibition by rotenone on APAP hepatoxicity. In this study, male BALB/c mice were pretreated with 250 ppm of rotenone in food for 3 days, then the animals were intraperitoneally injected with 300 mg/kg APAP. After 24 h APAP administration, animals developed severe liver injury as shown by the remarkable elevation of ALT and AST and hepatic centrilobular necrosis in line with the reduced liver GSH content. Strikingly, rotenone treatment markedly attenuated liver injury as shown by the improved liver enzyme release and liver morphology and enhanced liver GSH content. Meanwhile, rotenone ameliorated mitochondrial abnormality, inflammatory response and oxidative stress. Moreover, the downregulation of NOX4, a documented protector against APAP hepatotoxicity, was significantly restored by rotenone. However, mitochondrial complex III inhibitor AZOX failed to protect liver against APAP-induced injury. Together, these results suggested that inhibition of mitochondrial complex I but not mitochondrial complex III played a potent role in protecting against APAP hepatotoxicity.

Ghrelin attenuates UUO-induced renal fibrosis via attenuation of Nlrp3 inflammasome and endoplasmic reticulum stress

Background/aims: All chronic kidney disease (CKD) can eventually develop into renal fibrosis. We explored the renoprotective effects of a gastric peptide, ghrelin, and investigated whether endoplasmic reticulum stress (ERS) and the NLR family pyrin domain-containing 3 (NLRP3) inflammasome mediate the protective effect of ghrelin in unilateral ureteral obstruction (UUO).

METHODS

Male C57BL/6J mice were divided into vehicle- or ghrelin-treated sham-operated groups and vehicle- or ghrelin-treated UUO groups. The kidneys were harvested on postoperative day 14. Renal fibrosis was evaluated by periodic acid-Schiff, Masson trichrome, and immunohistochemical (IHC) staining. To assess renal fibrosis, α-smooth muscle actin and type I collagen were detected. NLRP3 inflammasome and ERS activation were also detected via western blotting. The effect of ghrelin on cultured renal cells was further confirmed in HK-2 cells.

RESULTS

Compared with the sham mice, UUO mice developed obvious renal fibrosis; pathological and IHC staining showed increased matrix accumulation and elevated ERS, NLRP3 inflammasome was activated both in vivo and in vitro. Ghrelin significantly attenuated collagen fibril accumulation and apoptosis by reducing NLRP3 inflammasome activation and ERS in obstructed kidneys.

CONCLUSIONS

Ghrelin may attenuate UUO-induced renal fibrosis by inhibiting the NLRP3 inflammasome and ERS in vivo. Therefore, ghrelin might be an effective strategy for preventing CKD.

Cordyceps militaris polysaccharides exerted protective effects on diabetic nephropathy in mice via regulation of autophagy

The present study is designed to investigate the protective effects of Cordyceps militaris polysaccharides (CMP) on STZ-treated DN mice.

MnTBAP treatment ameliorates aldosterone-induced renal injury by regulating mitochondrial dysfunction and NLRP3 inflammasome signalling

Aldosterone plays an important role in the pathogenesis of chronic kidney disease (CKD) by directly damaging renal tubular cells. However, the treatment against aldosterone-induced renal injury is still limited. The present study was performed to examine the protection role of MnTBAP in modulating aldosterone-induced renal tubular injury both in vitro and vivo. MtD is induced by aldosterone in HK-2 cells, as evidenced by decreased expression of mtDNA and reduced mitochondrial membrane potential (MMP), which was markedly ameliorated by treatment with MnTBAP. HK-2 cells treated with MnTBAP demonstrated a reduction in cell apoptosis and improvements in cell phenotypic alterations following aldosterone challenge. Treatment with MnTBAP also inhibited the activation of the NLRP3 inflammasome and subsequent release of pro-inflammatory cytokines, IL-1β and IL-18. In addition, MnTBAP treatment of aldosterone-infused mice significantly improved mitochondrial morphology and function, suppressed the activation of NLRP3 inflammasome, reduced renal tubular cell apoptosis, decreased phenotypic alterations, and ameliorated renal apoptosis. We conclude that MnTBAP treatment ameliorates aldosterone-induced renal injury through regulating MtD and NLRP3 inflammsome signalling axis.

Oxidative stress does not contribute to the release of proinflammatory cytokines through activating the Nod-like receptor protein 3 inflammasome in patients with obstructive sleep apnoea

PURPOSE

The study was conducted to test the hypothesis that oxidative stress leads to the release of proinflammatory cytokines by activating the Nod-like receptor protein (NLRP)3 inflammasome in patients with obstructive sleep apnoea (OSA).

METHODS

The study recruited 247 participants who were divided into cases and healthy control groups. OSA patients were subdivided into four subgroups according to sex, blood pressure, body mass index (BMI), and severity of disease. No significant differences were found between cases and controls with respect to age or sex. Peripheral blood samples were collected for analysis after examination, and the serum concentrations of oxidative stress (8-isoprostane), inflammation (interleukin (IL)-18, IL-1β, IL-6, tumour necrosis factor (TNF)-α), and NLRP3 inflammasome components (NLRP3, caspase-1, and ASC) were detected by enzyme-linked immunosorbent assay.

RESULTS

The serum concentrations of both oxidative stress and proinflammatory factors were higher in OSA patients than healthy controls. Subgroup analysis also revealed significant differences according to the apnoea-hypopnea index and BMI. Additionally, correlations were identified between 8-isoprostane and proinflammatory factors (IL-1β, IL-18, and TNF-α). Multiple regression analysis suggested that sleep parameters and BMI affected inflammation. However, no differences were observed in the serum level of NLRP3 inflammasome components between patients and controls. Furthermore, stratified analysis revealed no additional differences.

CONCLUSIONS

The current study suggests that oxidative stress leads to inflammation by mechanisms other than activation of the NLRP3 inflammasome in OSA patients. Furthermore, both sleep apnoea and BMI influenced the serum concentration of inflammatory mediators.

Plasma nesfatin-1 level is associated with severity of depression in Chinese depressive patients

BACKGROUND

Nesfatin-1 plays a role in the regulation of emotional states like depression. The aim of this study was to investigate the plasma nesfatin-1levels in Chinese patients with depression and healthy subjects, and to determine the possible association between the plasma nesfatin-1 level and the severity of depression.

METHODS

A total of 103 depressive patients and 32 healthy subjects were assessed. According to HAMD-17scores, 51, 18, and 34 patients were enrolled in the mild depression, moderate depression, and severe depression groups, respectively. Plasma nesfatin-1 levels were determined by the ELISA method. Differences between groups were compared and associations between plasma nesfatin-1 and other variables were analyzed.

RESULTS

The plasma nesfatin-1 was significantly positively correlated with HAMD-17 score (r = 0.651). Compared with healthy controls (8.11 ± 3.31 ng/mL), the plasma nesfatin-1 level significantly increased in patients with mild depression (11.17 ± 3.58 ng/mL), with moderate depression (16.33 ± 8.78 ng/mL), and with severe depression (27.65 ± 8.26 ng/mL) respectively. Plasma nesfatin-1 level (Odds ratio [OR] = 1.269) was an independent indicator for severe depression by multivariate logistic regression analysis.

CONCLUSION

The plasma nesfatin-1 level is positively correlated with the severity of depression. Plasma nesfatin-1 level may be a potential indicator for depression severity.

The effects of Desflurane and Sevoflurane on Nesfatin-1 levels in laparoscopic Cholecystectomy: a randomized controlled trial

Background

Nesfatin-1 is involved in cardiovascular regulation, stress-related responses. The objective of this study is to investigate the impact of volatile anesthetics on Nesfatin-1 levels.

Method

Fourty-two patients aged 30–65 years with the American Society Anesthesiology (ASA) Class I-II who were scheduled for laparoscopic cholecystectomy were included in the study Patients were randomized into two group; desflurane administered group (Group I, n = 21) and sevoflurane administered group (Group II, n = 21). For anesthesia maintenance, the patients received 6% desflurane or 2% sevoflurane in 40% O2 and 60% air. The patient’s heart rate (HR), mean, systolic and diastolic arterial pressures (MAP, SAP, DAP), peripheral O2 saturation (SpO2) were monitored and recorded before induction, after induction, after intubation, and during extubation. Blood samples were collected before induction (T1), and after extubation when aldrete score was 10 (T2).

Results

Demographic data were similar between the groups. The preoperative levels of nesfatin were similar in the two groups (p = 0.715). In desflurane group, post-operative nesfatin levels were similar compared to preoperative levels (p = 0.073). In sevoflurane group, post-operative nesfatin levels were similar (p = 0.131). The nesfatin levels (postoperative vs preoperative) were similar between the groups (p = 0.900).

Conclusion

In conclusion, this study results suggest that nesfatin-1 levels are not affected by the use of sevoflurane or desflurane in patients undergoing laparoscopic cholecystectomy.

Trial registration

Australian New Zealand Clinical Trials Registry, ACTRN12617001023347, retrospectively registered on 17 July 2017.

The NLPR3 inflammasome and obesity-related kidney disease

Over the past decade, the prevalence of obesity has increased, accompanied by a parallel increase in the prevalence of chronic kidney disease (CKD). Mounting evidence suggests that high body mass index (BMI) and obesity are important risk factors for CKD, but little is known about the mechanisms of obesity‐related kidney disease (ORKD). The NLRP3 inflammasome is a polyprotein complex that plays a crucial role in the inflammatory process, and numerous recent studies suggest that the NLRP3 inflammasome is involved in ORKD development and may serve as a key modulator of ORKD. Moreover, inhibiting activation of the NLRP3 inflammasome has been shown to attenuate ORKD. In this review, we summarize recent progress in understanding the link between the NLRP3 inflammasome and ORKD and discuss targeting the NLRP3 inflammasome as a novel therapeutic approach for ORKD.

Microbiome: A Potential Component in the Origin of Mental Disorders

It is not surprising to find microbiome abnormalities present in psychiatric disorders such as depressive disorders, bipolar disorders, etc. Evolutionary pressure may provide an existential advantage to the host eukaryotic cells in that it survives in an extracellular environment containing non-self cells (e.g., bacteria). This phenomenon is both positive and negative, as with other intercellular processes. In this specific case, the phenomenal amount of information gained from combined bacterial genome could enhance communication between self and non-self cells. This can be coupled to both pathological processes and healthy ones. In this review, we chose to examine potential associated disorders that may be coupled to the microbiome, from the perspective of their bidirectional communication with eukaryotic cells in the gut. Cognition, being the newest neural networking functionality to evolve, consumes a good amount of organismic energy, 30% of which arises from the gut flora. Furthermore, the mammalian gut is highly innervated and has a highly developed immune component, reflecting brain complexity. The brain-gut axis uses similar molecular messengers as the brain, which affects bacterial processes as well. Thus, any modification of normal bacterial processes may manifest itself in altered behavior/cognition, originating from the gut. The origin of some disorders associated with this bidirectional communication may be harnessed to restore normal functioning.

Aging Reversal and Healthy Longevity is in Reach: Dependence on Mitochondrial DNA Heteroplasmy as a Key Molecular Target

Recent trends in biomedical research have highlighted the potential for effecting significant extensions in longevity with enhanced quality of life in aging human populations. Within this context, any proposed method to achieve enhanced life extension must include therapeutic approaches that draw upon essential biochemical and molecular regulatory processes found in relatively simple single cell organisms that are evolutionarily conserved within complex organ systems of higher animals. Current critical thinking has established the primacy of mitochondrial function in maintaining good health throughout plant and animal phyla. The mitochondrion represents an existentially defined endosymbiotic model of complex organelle development driven by evolutionary modification of a permanently enslaved primordial bacterium. Cellular mitochondria are biochemically and morphologically tailored to provide exponentially enhanced ATP-dependent energy production accordingly to tissue- and organ-specific physiological demands. Thus, individual variations in longevity may then be effectively sorted according to age-dependent losses of single-cell metabolic integrity functionally linked to impaired mitochondrial bioenergetics within an aggregate presentation of compromised complex organ systems. Recent empirical studies have focused on the functional role of mitochondrial heteroplasmy in the regulation of normative cellular processes and the initiation and persistence of pathophysiological states. Accordingly, elucidation of the multifaceted functional roles of mitochondrial heteroplasmy in normal aging and enhanced longevity will provide both a compelling genetic basis and potential targets for therapeutic intervention to effect meaningful life extension in human populations.

NLRP3 Deficiency Attenuates Renal Fibrosis and Ameliorates Mitochondrial Dysfunction in a Mouse Unilateral Ureteral Obstruction Model of Chronic Kidney Disease

Background and Aims. The nucleotide-binding domain and leucine-rich repeat containing PYD-3 (NLRP3) inflammasome has been implicated in the pathogenesis of chronic kidney disease (CKD); however, its exact role in glomerular injury and tubulointerstitial fibrosis is still undefined. The present study was performed to identify the function of NLRP3 in modulating renal injury and fibrosis and the potential involvement of mitochondrial dysfunction in the murine unilateral ureteral obstruction (UUO) model of CKD. Methods. Employing wild-type (WT) and NLRP3^−/− mice with or without UUO, we evaluated renal structure, tissue injury, and mitochondrial ultrastructure, as well as expression of some vital molecules involved in the progression of fibrosis, apoptosis, inflammation, and mitochondrial dysfunction. Results. The severe glomerular injury and tubulointerstitial fibrosis induced in WT mice by UUO was markedly attenuated in NLRP3^−/− mice as evidenced by blockade of extracellular matrix deposition, decreased cell apoptosis, and phenotypic alterations. Moreover, NLRP3 deletion reversed UUO-induced impairment of mitochondrial morphology and function. Conclusions. NLRP3 deletion ameliorates mitochondrial dysfunction and alleviates renal fibrosis in a murine UUO model of CKD.

The effects of rotenone-induced toxicity via the NF-κB-iNOS pathway in rat liver

Rotenone has been used as a pesticide for many years, it is an environmental poison reported to cause neurological diseases. However, the effects of rotenone on the rat liver are unclear, as are the mechanisms of toxicity. In the present study, Sprague-Dawley (SD) rats were divided into five groups: control, dimethyl sulfoxide (DMSO), rotenone low-dose (1 mg/kg), rotenone mid-dose (2 mg/kg) and rotenone high-dose (4 mg/kg). The treatments were orally administered daily for 28 days, we assessed health status, mRNA expression levels of inflammatory factors, protein levels, nitric oxide (NO) content and histological changes. The results showed that body weight was significantly decreased in each rotenone group in a dose-dependent manner, compared with the control group. Rotenone significantly increased the mRNA levels of cyclooxygenase-2 (COX-2), nuclear factor kappaB (NF-κB), prostaglandin E₂ (PGE₂), inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF-α) in each rotenone group compared with the control group, except iNOS and TNF-α mRNA expression in the low-dose group. The protein levels of COX-2 were significantly higher in each rotenone group compared with the control group, NF-κB protein expression were significantly higher in the rotenone mid and high-dose groups, but not in the low-dose group, compared with the control group, similar changes were observed in NO content. Additionally, histological analysis revealed that the most severe tissue damage occurred in the high-dose group. These results indicated that rotenone has toxic effect in rat liver relating to inflammatory factors. Our findings provide insight into the mechanisms of rotenone hepatotoxicity.

Mitochondrial reactive oxygen species-mediated NLRP3 inflammasome activation contributes to aldosterone-induced renal tubular cells injury

Aldosterone (Aldo) is an independent risk factor for chronic kidney disease (CKD), and although Aldo directly induces renal tubular cell injury, the underlying mechanisms remain unclear. NLRP3 inflammasome and mitochondrial reactive oxygen species (ROS) have recently been implicated in various kinds of CKD. The present study hypothesized that mitochondrial ROS and NLRP3 inflammasome mediated Aldo–induced tubular cell injury. The NLRP3 inflammasome is induced by Aldo in a dose- and time-dependent manner, as evidenced by increased NLRP3, ASC, caspase-1, and downstream cytokines, such as interleukin (IL)-1β and IL-18. The activation of the NLRP3 inflammasome was significantly prevented by the selective mineralocorticoid receptor (MR) antagonist eplerenone (EPL) (P < 0.01). Mice harboring genetic knock-out of NLRP3 (NLRP3^−/−) showed decreased maturation of renal IL-1β and IL-18, reduced renal tubular apoptosis, and improved renal epithelial cell phenotypic alternation, and attenuated renal function in response to Aldo-infusion. In addition, mitochondrial ROS was also increased in Aldo-stimulated HK-2 cells, as assessed by MitoSOX^TM red reagent. Mito-Tempo, the mitochondria-targeted antioxidant, significantly decreased HK-2 cell apoptosis, oxidative stress, and the activation of NLRP3 inflammasome. We conclude that Aldo induces renal tubular cell injury via MR dependent, mitochondrial ROS-mediated NLRP3 inflammasome activation.

NLRP3 inflammasome activation contributes to aldosterone-induced podocyte injury

Aldosterone (Aldo) has been shown as an important contributor of podocyte injury. However, the underlying molecular mechanisms are still elusive. Recently, the pathogenic role of NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome in mediating renal tubular damage was identified while its role in podocyte injury still needs evidence. Thus the present study was undertaken to investigate the role of NLRP3 inflammasome in Aldo-induced podocyte damage. In vitro, exposure of podocytes to Aldo enhanced NLRP3, caspase-1, and IL-18 expressions in dose- and time-dependent manners, indicating an activation of NLRP3 inflammasome, which was significantly blocked by the mineralocorticoid receptor antagonist eplerenone or the antioxidant N-acetylcysteine. Silencing NLRP3 by a siRNA approach strikingly attenuated Aldo-induced podocyte apoptosis and nephrin protein downregulation in line with the blockade of caspase-1 and IL-18. In vivo, since day 5 of Aldo infusion, NLRP3 inflammasome activation and podocyte injury evidenced by nephrin reduction occurred concurrently. More importantly, immunofluorescence analysis showed a significant induction of NLRP3 in podocytes of glomeruli following Aldo infusion. In the mice with NLRP3 gene deletion, Aldo-induced downregulation of nephrin and podocin, podocyte foot processes, and albuminuria was remarkably improved, indicating an amelioration of podocyte injury. Finally, we observed a striking induction of NLRP3 in glomeruli and renal tubules in line with an enhanced urinary IL-18 output in nephrotic syndrome patients with minimal change disease or focal segmental glomerular sclerosis. Together, these results demonstrated an important role of NLRP3 inflammasome in mediating the podocyte injury induced by Aldo.

Endoplasmic Reticulum Chaperon Tauroursodeoxycholic Acid Attenuates Aldosterone-Infused Renal Injury

Aldosterone (Aldo) is critically involved in the development of renal injury via the production of reactive oxygen species and inflammation. Endoplasmic reticulum (ER) stress is also evoked in Aldo-induced renal injury. In the present study, we investigated the role of ER stress in inflammation-mediated renal injury in Aldo-infused mice. C57BL/6J mice were randomized to receive treatment for 4 weeks as follows: vehicle infusion, Aldo infusion, vehicle infusion plus tauroursodeoxycholic acid (TUDCA), and Aldo infusion plus TUDCA. The effect of TUDCA on the Aldo-infused inflammatory response and renal injury was investigated using periodic acid-Schiff staining, real-time PCR, Western blot, and ELISA. We demonstrate that Aldo leads to impaired renal function and inhibition of ER stress via TUDCA attenuates renal fibrosis. This was indicated by decreased collagen I, collagen IV, fibronectin, and TGF-β expression, as well as the downregulation of the expression of Nlrp3 inflammasome markers, Nlrp3, ASC, IL-1β, and IL-18. This paper presents an important role for ER stress on the renal inflammatory response to Aldo. Additionally, the inhibition of ER stress by TUDCA negatively regulates the levels of these inflammatory molecules in the context of Aldo.

Epidermal growth factor receptor signaling mediates aldosterone-induced profibrotic responses in kidney

Aldosterone has been recognized as a risk factor for the development of chronic kidney disease (CKD). Studies have indicated that enhanced activation of epidermal growth factor receptor (EGFR) is associated with the development and progression of renal fibrosis. But if EGFR is involved in aldosterone-induced renal fibrosis is less investigated. In the present study, we examined the effect of erlotinib, an inhibitor of EGFR tyrosine kinase activity, on the progression of aldosterone-induced renal profibrotic responses in a murine model underwent uninephrectomy. Erlotinib-treated rats exhibited relieved structural lesion comparing with rats treated with aldosterone alone, as characterized by glomerular hypertrophy, mesangial cell proliferation and expansion. Also, erlotinib inhibited the expression of TGF-β, α-SMA and mesangial matrix proteins such as collagen Ⅳ and fibronectin. In cultured mesangial cells, inhibition of EGFR also abrogated aldosterone-induced expression of extracellular matrix proteins, cell proliferation and migration. We also demonstrated that aldosterone induced the phosphorylation of EGFR through generation of ROS. And the activation of EGFR resulted in the phosphorylation of ERK1/2, leading to the activation of profibrotic pathways. Taken together, we concluded that aldosterone-mediated tissue fibrosis relies on ROS induced EGFR/ERK activation, highlighting EGFR as a potential therapeutic target for modulating renal fibrosis.

NLRP3 deletion protects against renal fibrosis and attenuates mitochondrial abnormality in mouse with 5/6 nephrectomy

Progressive fibrosis in chronic kidney disease (CKD) is the well-recognized cause leading to the progressive loss of renal function. Emerging evidence indicated a pathogenic role of the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome in mediating kidney injury. However, the role of NLRP3 in the remnant kidney disease model is still undefined. The present study was undertaken to evaluate the function of NLRP3 in modulating renal fibrosis in a CKD model of 5/6 nephrectomy (5/6 Nx) and the potential involvement of mitochondrial dysfunction in the pathogenesis. Employing NLRP3+/+ and NLRP3−/− mice with or without 5/6 Nx, we examined renal fibrotic response and mitochondrial function. Strikingly, tubulointerstitial fibrosis was remarkably attenuated in NLRP3−/− mice as evidenced by the blockade of extracellular matrix deposition. Meanwhile, renal tubular cells in NLRP3−/− mice maintained better mitochondrial morphology and higher mitochondrial DNA copy number, indicating an amelioration of mitochondrial abnormality. Moreover, NLRP3 deletion also blunted the severity of proteinuria and CKD-related hypertension. To further evaluate the direct role of NLRP3 in triggering fibrogenesis, mouse proximal tubular cells (PTCs) were subjected to transforming growth factor β1 (TGF-β1), and the cellular phenotypic changes were detected. As expected, TGF-β1-induced alterations of PTC phenotype were abolished by NLRP3 small interfering RNA, in line with a protection of mitochondrial function. Taken together, NLRP3 deletion protected against renal fibrosis in the 5/6 Nx disease model, possibly via inhibiting mitochondrial dysfunction.