KEY POINTS:Integrated stress response promotes drug-induced AKI. Activating transcription factor 4 promoted tubular epithelial cell pyroptosis in drug-induced AKI by activating signal transducer and activator of transcription 1-guanylate-binding protein 2 signaling. BACKGROUND:Pyroptosis plays a critical role in eliminating pathogens and facilitating tissue repair; however, sustained pyroptosis-driven inflammation accelerates kidney injury and disease progression. Thus, elucidating the mechanisms governing pyroptosis is essential for developing effective therapies for inflammatory kidney diseases, such as AKI, which currently lacks specific treatment options. METHODS:Changes in tubular epithelial cells (TEC) after drug-induced AKI were assessed using single-cell RNA sequencing, immunohistochemistry, and immunofluorescence. Mechanistic insights were obtained through RNA sequencing, genomic manipulation, transcriptomic profiling, luciferase reporter assays, coimmunoprecipitation, and Western blotting. TEC fate was further evaluated using transgenic mouse models and pharmacological interventions. RESULTS:We identified activating transcription factor 4 (ATF4) as a key regulator of inflammation in drug-induced AKI. As the master regulator of the integrated stress response, ATF4 was markedly upregulated in renal tubules and positively correlated with kidney dysfunction in both human and murine AKI models. The specific deletion of ATF4 in TECs significantly ameliorated kidney dysfunction, inflammation, and mitochondrial apoptosis, whereas ATF4 activation exacerbated these pathological features. Mechanistically, ATF4 suppression inhibited signal transducer and activator of transcription 1 phosphorylation and disrupted its interaction with guanylate-binding protein 2, thereby attenuating NLR family pyrin domain-containing 3 inflammasome activation, preventing TECs' pyroptosis, and improving kidney function. Notably, inhibition of ATF4-either pharmacologically using our prioritized integrated stress response antagonist ERMT1 or through engineered nanobiologics-mediated silencing of TECs-significantly reduced renal inflammation and injury. CONCLUSIONS:ATF4 promoted pyroptosis in drug-induced AKI through signal transducer and activator of transcription 1-guanylate-binding protein 2 signaling.

Key PointsIntegrated stress response promotes drug-induced AKI.Activating transcription factor 4 promoted tubular epithelial cell pyroptosis in drug-induced AKI by activating signal transducer and activator of transcription 1-guanylate-binding protein 2 signaling.BackgroundPyroptosis plays a critical role in eliminating pathogens and facilitating tissue repair; however, sustained pyroptosis-driven inflammation accelerates kidney injury and disease progression. Thus, elucidating the mechanisms governing pyroptosis is essential for developing effective therapies for inflammatory kidney diseases, such as AKI, which currently lacks specific treatment options.MethodsChanges in tubular epithelial cells (TEC) after drug-induced AKI were assessed using single-cell RNA sequencing, immunohistochemistry, and immunofluorescence. Mechanistic insights were obtained through RNA sequencing, genomic manipulation, transcriptomic profiling, luciferase reporter assays, coimmunoprecipitation, and Western blotting. TEC fate was further evaluated using transgenic mouse models and pharmacological interventions.ResultsWe identified activating transcription factor 4 (ATF4) as a key regulator of inflammation in drug-induced AKI. As the master regulator of the integrated stress response, ATF4 was markedly upregulated in renal tubules and positively correlated with kidney dysfunction in both human and murine AKI models. The specific deletion of ATF4 in TECs significantly ameliorated kidney dysfunction, inflammation, and mitochondrial apoptosis, whereas ATF4 activation exacerbated these pathological features. Mechanistically, ATF4 suppression inhibited signal transducer and activator of transcription 1 phosphorylation and disrupted its interaction with guanylate-binding protein 2, thereby attenuating NLR family pyrin domain-containing 3 inflammasome activation, preventing TECs' pyroptosis, and improving kidney function. Notably, inhibition of ATF4-either pharmacologically using our prioritized integrated stress response antagonist ERMT1 or through engineered nanobiologics-mediated silencing of TECs-significantly reduced renal inflammation and injury.ConclusionsATF4 promoted pyroptosis in drug-induced AKI through signal transducer and activator of transcription 1-guanylate-binding protein 2 signaling.

BACKGROUND:Inflammation and oxidative stress are important pathological processes of contrast-induced acute renal injury (CIAKI). This study explored whether DMF had therapeutic effects and investigated the underlying mechanism in CIAKI. METHODS:A CIAKI animal model was established in C57BL/6J mice with iohexol, and DMF was used as an intervention. In vitro, HK-2 cells were treated with iohexol and DMF. RNA-seq analysis was performed on the renal tissue of the mice. Protein-protein interaction (PPI), and enrichment analysis were subsequently conducted. In addition, endoplasmic reticulum stress (ERS) activation and STAT3 inhibition were used to study the relationships among ERS, the JAK2-STAT3 pathway and pyroptosis. RESULTS:DMF improved the renal function of CIAKI model mice. Enrichment analysis revealed that the differentially expressed genes (DEGs) were enriched mostly in the acute phase response and the JAK-STAT pathway. The results revealed that inflammation, ERS and pyroptosis increased in the CIAKI group but decreased after DMF treatment. Further study revealed that the JAK2-STAT3 pathway was overactivated in vivo and in vitro and that DMF inhibited the JAK2-STAT3 pathway. In addition, ERS activation could increase the JAK2-STAT3 pathway and pyroptosis, while STAT3 knockdown could reverse pyroptosis, indicating that ERS could activate the JAK2-STAT3 pathway, further triggering pyroptosis. DMF ameliorated pyroptosis through regulating ERS and the JAK2-STAT3 pathway in CIAKI. CONCLUSION:This study demonstrated that DMF had renoprotective effects on CIAKI. DMF ameliorated pyroptosis through the inhibition of ERS and the JAK2-STAT3 pathway.

Abstract Background The treatment options to delay the progression of diabetic nephropathy (DN), a key contributor to chronic kidney disease (CKD), are urgently needed. Previous studies reported that traditional Chinese medicine Panax notoginseng (PNG) exerted beneficial effects on DN. However, the renoprotective effects of Notoginsenoside R2 (NR2), an active component of PNG, on DN have not been investigated. This study aimed to assess the therapeutic potential of NR2 in DN and explore its underlying mechanisms. Methods In vivo models were developed using db/db mice, while in vitro models utilized HK-2 cells exposed to high glucose and palmitic acid (HGPA). Online databases and Cytoscape software were employed to predict the potential targets of NR2. The expression of associated proteins was measured using immunohistochemistry and western blot. Lipid accumulation, oxidative stress levels, mitochondrial function and cell apoptosis were also assessed. Small interfering RNA was used in in vitro experiments to examine the effect of c-Src. Results NR2 ameliorated albuminuria, renal function and renal pathology in db/db mice. The activation of c-Src was suppressed in db/db mice and in HK-2 cells exposed to HGPA. NR2 inhibited JNK/STAT1 phosphorylation and CD36 overexpression. NR2 also ameliorated lipid accumulation, oxidative stress, mitochondrial dysfunction and cell apoptosis in vivo and in vitro. By inhibiting c-Src, HK-2 cells exposed to HGPA experienced less lipid deposition and mitochondrial damage, indicating the renoprotective effects of NR2 were correlated with the inhibition of c-Src. Conclusion NR2 ameliorated mitochondrial dysfunction and delayed the progression of DN partly through suppression of c-Src. The protective effects of NR2 might be related to a reduction in lipid accumulation. Graphical Abstract

ETHNOPHARMACOLOGICAL RELEVANCE:Qingyihuaji Formula (QYHJ) has been used to treat human pancreatic cancer for many years and are fully documented in the Pharmacopoeia of the People's Republic of China (2020 Edition), however, its pharmacological mechanisms remain largely unknown. AIM OF THE STUDY:Here, we aimed to provide evidences for uncovering the underlying molecular mechanisms of QYHJ for pancreatic cancer management. MATERIALS AND METHODS:Bioinformatic analysis, quantitative real-time PCR, western blotting, glucose consumption, immunofluorescence and glycolytic activity assay were performed to determine the underlying mechanisms. The effects of QYHJ treatment, overexpression or knockdown of LINC00346 and ATF4 on the cell proliferation, migration, cellular ROS, apoptosis and metabolism were investigated. A xenograft mouse model was further established to evaluate the mechanism in vivo. RESULTS:We found that QYHJ inhibits LINC00346-OMA1-ATF4 signal transduction and aerobic glycolysis in pancreatic cancer cells. Overexpression of LINC00346 and ATF4 reversed the inhibition of glycolytic metabolism and growth-suppressive effects after QYHJ treatment in vitro and in vivo. Moreover, there was a significant negative correlation between expression levels of LINC00346-OMA1 with overall survival in patients with pancreatic cancer and a positive correlation between OMA1 and ATF4 levels in human tumors. CONCLUSION:Our findings indicate QYHJ shows the ability to suppress pancreatic cancer growth and progression, which is in mediated through antagonization of LINC00346 and activation of OMA1-ATF4. Targeting LINC00346-OMA1-ATF4 signaling may be promising effective therapeutic strategies for pancreatic cancer intervention.

Background: Diabetic nephropathy (DN) is the primary cause of end-stage renal disease (ESRD), and the therapeutic strategies for DN are limited. Notoginsenoside Fc (Fc), a novel saponin isolated from Panax Notoginseng (PNG), has been reported to alleviate vascular injury in diabetic rats. However, the protective effects of Fc on DN remain unclear. Purpose: To investigate the beneficial effects and mechanisms of Fc on DN. Methods: Db/db mice were treated with 2.5, 5 and 10 mg center dot kg(-1)center dot d(-1) of Fc for 8 weeks. High glucose (HG) induced mouse glomerular endothelial cells (GECs) were treated with 2.5, 5 and 10 mu M of Fc for 24 h. Results: Our data found that Fc ameliorated urinary microalbumin level, kidney dysfunction and histopathological damage in diabetic mice. Moreover, Fc alleviated the accumulation of oxidative stress, the collapse of mitochondrial membrane potential and the expression of mitochondrial fission proteins, such as Drp-1 and Fis1, while increased the expression of mitochondrial fusion protein Mfn2. Fc also decreased pyroptosis-related proteins levels, such as TXNIP, NLRP3, cleaved caspase-1, and GSDMD-NT, indicating that Fc ameliorated GECs pyroptosis. In addition, 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) expression was increased in diabetic group, which was partially abrogated by Fc. Our data further proved that knockdown of HMGCS2 could restrain HG-induced GECs mitochondrial dysfunction and pyroptosis. These results indicated that the inhibitory effects of Fc on mitochondrial damage and pyroptosis were associated with the suppression of HMGCS2. Conclusion: Taken together, this study clearly demonstrated that Fc ameliorated GECs pyroptosis and mitochondrial dysfunction partly through regulating HMGCS2 pathway, which might provide a novel drug candidate for DN.

Axons have intrinsically poor regenerative capacity in the mature central nervous system (CNS), leading to permanent neurological impairments in individuals. There is growing evidence that exercise is a powerful physiological intervention that can obviously enhance cell rejuvenate capacity, but its molecular mechanisms that mediate the axonal regenerative benefits remain largely unclear. Using the eye as the CNS model, here it is first indicated that placing mice in an exercise stimulation environment induced DNA methylation patterns and transcriptomes of retinal ganglion cell, promoted axon regeneration after injury, and reversed vision loss in aged mice. These beneficial effects are dependent on the DNA demethylases TET3-mediated epigenetic effects, which increased the expression of genes associated with the regenerative growth programs, such as STAT3, Wnt5a, Klf6. Exercise training also shows with the improved mitochondrial and metabolic dysfunction in retinas and optic nerves via TET3. Collectively, these results suggested that the increased regenerative capacity induced by enhancing physical activity is mediated through epigenetic reprogramming in mouse model of optic nerve injury and in aged mouse. Understanding the molecular mechanism underlying exercise-dependent neuronal plasticity led to the identification of novel targets for ameliorating pathologies associated with etiologically diverse diseases.

Abstract Acute kidney injury (AKI) is a disease with high morbidity and mortality and ischemia-reperfusion (IR) injury is the main cause of AKI. It has been reported that hyperglycemia was a crucial risk factor for renal IRI in diabetes patients with renal IR-induced AKI. Whereas there is no effective treatment. Here, we explored the nephroprotective effects of combination of Astragaloside II and Notoginsenoside Fc on diabetes with IR-induced AKI and its potential mechanisms. We established hyperglycemia with renal hypoxia reoxygenation (H/R) injury model in vivo and in vitro. We first found that combination of Astragaloside II and Notoginsenoside Fc could improve biochemical indexes and renal histologic injury in model mice. We provided relevant evidence that combination of Astragaloside II and Notoginsenoside Fc significantly reduced apoptosis level. In addition, our data suggested that combination of Astragaloside II and Notoginsenoside Fc could have inhibited effects on oxidative stress and NLRP3 activation, further suppressing inflammatory cell aggregation and inflammatory factor secretion. Further studies found that the combination of Astragaloside II and Notoginsenoside Fc could prevent SHP-1-induced VEGF inhibition and activate PDGFB to ameliorate renal tubular epithelial cells (TECs) function. In conclusion, our study indicated that combined treatment of Astragaloside II and Notoginsenoside Fc exerted beneficial protective effects on renal tubular injury and mitochondrial oxidative stress in diabetes with ischemia-reperfusion induced AKI via activating PDGFB and inhibiting SHP-1/VEGFA signaling pathway. Therefore, combination of Astragaloside II and Notoginsenoside Fc may be a potential therapeutic strategy to treat diabetes with IR-induced AKI.

Introduction Mitochondria dysfunction is one of the primary causes of tubular injury in acute kidney injury (AKI). Notoginsenoside Fc (Fc), a new saponin isolated from Panax notoginseng, exhibited numerous pharmacological actions. However, the beneficial effects of Fc on renal tubular impairment and mitochondrial dysfunction in AKI have not been fully studied. Methods In this study, we established acetaminophen (APAP)-induced AKI model in mice to examine the therapeutic impacts of Fc on AKI. Results Our results showed that Fc could decrease the levels of the serum creatinine (Scr), blood urea nitrogen (BUN) and Cystatin C in mice with AKI. Fc also ameliorated renal histopathology, renal tubular cells apoptosis and restored expression of apoptosis-related proteins such as Bax, Bcl-2 and caspase3 (C-caspase3). Additionally, Fc increased the protein expression of SIRT3 and SOD2 in kidneys from mice with AKI. In vitro studies further showed Fc reduced the apoptosis of HK-2 cells exposure to APAP, attenuated the loss of mitochondrial membrane potential and decreased the formation of mitochondrial superoxide. Fc also partly restored the protein expression of Bax, Bcl-2, C-Caspase3, SIRT3, and SOD2 in HK-2 cells exposure to APAP. Conclusion In summary, Fc might reduce renal tubular injury and mitochondrial dysfunction in AKI partly through the regulation of SIRT3/SOD2 pathway.

The pathogenesis of diabetic kidney disease (DKD) is complicated. Current clinical treatments fail to achieve satisfactory efficacy in the prevention of DKD progression, it urgently needs novel and effective treatment for DKD. In this study, we firstly demonstrated that renal lipid metabolism abnormality and inflammation significantly changed in DKD conditions by mining public transcriptomic data of DKD patient samples. KEGG analysis further exhibited the critical role of vascular endothelial growth factor B (VEGF-B) and interleukin 17A (IL-17A) signal pathways in DKD progression, indicating that VEGF-B and IL-17A might be the promising targets for DKD treatment. Then the potential of a novel combination therapy, anti-VEGF-B plus anti-IL-17A antibody, was evaluated for DKD treatment. Our results demonstrated that simultaneous blockade of VEGF-B and IL-17A signaling with their neutralizing antibodies alleviated renal damage and ameliorated renal function. The therapeutic effectiveness was not only related to the reduced lipid deposition especially the neutral lipids in kidney but also associated with the decreased inflammation response. Moreover, the therapy alleviated renal fibrosis by reducing collagen deposition and the expression of fibronectin and α-SMA in kidney tissues. RNA-seq analysis indicated that differential expression genes (DEGs) in db/db mice were significantly clustered into lipid metabolism, inflammation, fibrosis and DKD pathology-related pathways, and 181 of those DEGs were significantly reversed by the combinatory treatment, suggesting the underlying mechanism of administration of anti-VEGF-B and anti-IL-17A antibodies in DKD treatment. Taken together, this study identified that renal lipid metabolism abnormality and inflammation were critically involved in the progression of DKD, and simultaneous blockade of VEGF-B and IL-17A signaling represents a potential DKD therapeutic strategy.

Diabetic nephropathy (DN), the principal pathogeny of end-stage renal disease (ESRD), is related to metabolic disorders, chronic inflammation, and oxidative stress. It was reported that high expression of interleukin-17A (IL-17A) was intimately related to the progression of DN, and targeting IL-17A exhibited regulating effects on inflammation and autoimmunity but had only limited impact on the oxidative stress damage in DN. Recent studies showed that interleukin-22 (IL-22) could inhibit mitochondrial damage and inflammatory response. Thus, the cytokine IL-22 was first fused to anti-IL-17A antibody for endowing the antibody with the anti-hyperglycemia and anti-inflammation activity. Our study demonstrated that the fusion molecule, anti-IL17A/IL22 fusion protein, could not only lead to the increase of M1 macrophages and the decrease of M2 macrophages, further improving the immune microenvironment, but also prevent the loss of mitochondrial membrane potential by reducing the production of ROS in murine DN model. In addition, the fusion protein could block TRAF6/NF-κB and AKT/ROS/TXNIP signaling pathways, further synergistically restraining the production of NLRP3, thus suppressing the inflammatory response and playing beneficial effect on slowing down the progression of DN. In conclusion, our findings demonstrated that the bifunctional IL-17A antibody and IL-22 fusion protein were of great benefit to DN, which highlighted a potential therapeutic strategy. KEY POINTS: • Anti-IL17A/IL22 fusion protein could improve the immune microenvironment and reduce the production of ROS. • Anti-IL17A/IL22 fusion protein could block TRAF6/NF-κB and AKT/ROS/TXNIP signaling pathways and then restrain the activation of NLRP3.

Oxalate-induced crystalline kidney injury is one of the most common types of crystalline nephropathy. Unfortunately, there is no effective treatment to reduce the deposition of calcium oxalate crystals and alleviate kidney damage. Thus, proactive therapeutic is urgently needed to alleviate the suffering it causes to patient. Here, we investigated whether IL-22 exerted nephroprotective effects to sodium oxalate-mediated kidney damage and its potential mechanism. Crystalline kidney injury models were developed in vitro and in vivo that was often observed in clinic. We provided evidence that IL-22 could effectively decrease the accumulation of ROS and mitochondrial damage in cell and animal models and reduce the death of TECs. Moreover, IL-22 decreased the expression of the NLRP3 inflammasome and mature IL-1β in renal tissue induced by sodium oxalate. Further studies confirmed that IL-22 could play an anti-inflammatory role by reducing the levels of cytokines such as IL-1β, IL-18, and TNF-α in serum. In conclusion, our study confirmed that IL-22 has protective effects on sodium oxalate-induced crystalline kidney injury by reducing the production of ROS, protecting mitochondrial membrane potential, and inhibiting the inflammatory response. Therefore, IL-22 may play a potential preventive role in sodium oxalate-induced acute renal injury. KEY POINTS: • IL-22 could reduce sodium oxalate-mediated cytotoxicity and ameliorate renal injury. • IL-22 could alleviate oxidative stress and mitochondrial dysfunction induced by sodium oxalate. • IL-22 could inhibit inflammatory response of renal injury caused by sodium oxalate.

Mitochondrial abnormality is one of the main factors of tubular injury in diabetic nephropathy (DN). Formononetin (FMN), a novel isoflavonoid isolated from Astragalus membranaceus, has diverse pharmacological activities. However, the beneficial effects of FMN on renal tubular impairment and mitochondrial dysfunction in DN have yet to be studied. In this study, we performed in vivo tests in Streptozotocin (STZ) -induced diabetic rats to explore the therapeutic effects of FMN on DN. We demonstrated that FMN could ameliorate albuminuria and renal histopathology. FMN attenuated renal tubular cells apoptosis, mitochondrial fragmentation and restored expression of mitochondrial dynamics-associated proteins, such as Drp1, Fis1 and Mfn2, as well as apoptosis-related proteins, such as Bax, Bcl-2 and cleaved-caspase-3. Moreover, FMN upregulated the protein expression of Sirt1 and PGC-1α in diabetic kidneys. In vitro studies further demonstrated that FMN could inhibit high glucose-induced apoptosis of HK-2 cells. FMN also reduced the production of mitochondrial superoxide and alleviated mitochondrial membrane potential (MMP) loss. Furthermore, FMN partially restored the protein expression of Drp1, Fis1 and Mfn2, Bax, Bcl-2, cleaved-caspase-3, Sirt1 and PGC-1α in HK-2 cells exposure to high glucose. In conclusion, FMN could attenuate renal tubular injury and mitochondrial damage in DN partly by regulating Sirt1/PGC-1α pathway.

植物药被广泛用于治疗疾病己有数千年的历史,对人类健康起到重要作用.植物药中含有多种天然化合物,活性成分相对复杂,可能会产生不同程度的不良反应.植物药中可以造成肾毒性的成分主要是马兜铃酸和其他植物生物碱.此外,植物药中的黄酮类、蒽醌类和糖苷类也可能会引起肾毒性.本文旨在论述引起肾毒性的植物药中的有毒成分,此类有毒成分的毒性机制以及防治策略,以期为植物药合理使用提供参考.

Astragaloside II (AS II), a novel saponin purified from Astragalus membranes, has been reported to modulate the immune response, repair tissue injury, and prevent inflammatory response. However, the protective effects of AS II on podocyte injury in diabetic nephropathy (DN) have not been investigated yet. In this study, we aimed to investigate the beneficial effects of AS II on podocyte injury and mitochondrial dysfunction in DN. Diabetes was induced with streptozotocin (STZ) by intraperitoneal injection at 55 mg/kg in rats. Diabetic rats were randomly divided into four groups, namely, diabetic rats and diabetic rats treated with losartan (10 mg·kg−1·d−1) or AS II (3.2 and 6.4 mg·kg−1·d−1) for 9 weeks. Normal Sprague-Dawley rats were chosen as nondiabetic control group. Urinary albumin/creatinine ratio (ACR), biochemical parameters, renal histopathology and podocyte apoptosis, and morphological changes were evaluated. Expressions of mitochondrial dynamics-related and autophagy-related proteins, such as Mfn2, Fis1, P62, and LC3, as well as Nrf2, Keap1, PINK1, and Parkin, were examined by immunohistochemistry, western blot, and real-time PCR, respectively. Our results indicated that AS II ameliorated albuminuria, renal histopathology, and podocyte foot process effacement and podocyte apoptosis in diabetic rats. AS II also partially restored the renal expression of mitochondrial dynamics-related and autophagy-related proteins, including Mfn2, Fis1, P62, and LC3. AS II also increased the expression of PINK1 and Parkin associated with mitophagy in diabetic rats. Moreover, AS II facilitated antioxidative stress ability via increasing Nrf2 expression and decreasing Keap1 protein level. These results suggested that AS II ameliorated podocyte injury and mitochondrial dysfunction in diabetic rats partly through regulation of Nrf2 and PINK1 pathway. These important findings might provide an innovative therapeutic strategy for the treatment of DN.

AbstractKidney damage initiates the deteriorating metabolic states in tubule cells that lead to the development of end‐stage renal disease (ESTD). Interleukin‐22 (IL‐22) is an effective therapeutic antidote for kidney injury via promoting kidney recovery, but little is known about the underlying molecular mechanisms. Here, we first provide evidence that IL‐22 attenuates kidney injury via metabolic reprogramming of renal tubular epithelial cells (TECs). Specifically, our data suggest that IL‐22 regulates mitochondrial function and glycolysis in damaged TECs. Further observations indicate that IL‐22 alleviates the accumulation of mitochondrial reactive oxygen species (ROS) and dysfunctional mitochondria via the induction of AMPK/AKT signaling and PFBFK3 activities. In mice, amelioration of kidney injury and necrosis and improvement of kidney functions via regulation of these metabolism relevant signaling and mitochondrial fitness of recombinant IL‐22 are certificated in cisplatin‐induced kidney damage and diabetic nephropathy (DN) animal models. Taken together, our findings unravel new mechanistic insights into protective effects of IL‐22 on kidneys and highlight the therapeutic opportunities of IL‐22 and the involved metabolic regulators in various kidney diseases.

Acetaminophen (APAP) overdose can lead to acute, severe kidney injury, which has recently attracted considerable attention among researchers and clinicians. Unfortunately, there are no well-established treatments for APAP-induced renal injury, and the molecular mechanism of APAP-induced kidney injury is still unclear. Herein, we explored the protective effects of interleukin (IL)-22 on APAP-induced renal injury and the underlying molecular basis. We found that IL-22 could significantly alleviate the accumulation of reactive oxygen species (ROS) and ameliorate mitochondrial dysfunction, reducing APAP-induced renal tubular epithelial cell (TEC) death in vitro and in vivo. Furthermore, IL-22 could downregulate the APAP-induced NLRP3 inflammasome activation and mature IL-1β release in kidney injury. Additionally, the APAP-mediated upregulation of the serum levels of IL-18, TNF-α, IL-6, and IL-1β was obviously decreased, suggesting IL-22 has inhibitory effects on inflammatory responses. Conclusively, our study demonstrated that IL-22 exerted ameliorative effects on APAP-induced kidney injury by alleviating mitochondrial dysfunction and NLRP3 inflammasome activation, suggesting that IL-22 represents a potential therapeutic approach to treat APAP-induced kidney injury. KEY POINTS: • IL-22 could ameliorate APAP that triggered oxidative stress and mitochondrial dysfunction. • IL-22 could reduce APAP that caused inflammatory responses. Graphical abstract.

Diabetic nephropathy (DN) is considered the primary causes of end-stage renal disease (ESRD) and is related to abnormal glycolipid metabolism, hemodynamic abnormalities, oxidative stress and chronic inflammation. Antagonism of vascular endothelial growth factor B (VEGF-B) could efficiently ameliorate DN by reducing renal lipotoxicity. However, this pharmacological strategy is far from satisfactory, as it ignores numerous pathogenic factors, including anomalous reactive oxygen species (ROS) generation and inflammatory responses. We found that the upregulation of VEGF-B and downregulation of interleukin-22 (IL-22) among DN patients were significantly associated with the progression of DN. Thus, we hypothesized that a combination of a VEGF-B antibody and IL-22 could protect against DN not only by regulating glycolipid metabolism but also by reducing the accumulation of inflammation and ROS. To meet these challenges, a novel anti-VEGFB/IL22 fusion protein was developed, and its therapeutic effects on DN were further studied. We found that the anti-VEGFB/IL22 fusion protein reduced renal lipid accumulation by inhibiting the expression of fatty acid transport proteins and ameliorated inflammatory responses via the inhibition of renal oxidative stress and mitochondrial dysfunction. Moreover, the fusion protein could also improve diabetic kidney disease by increasing insulin sensitivity. Collectively, our findings indicate that the bifunctional VEGF-B antibody and IL-22 fusion protein could improve the progression of DN, which highlighted a novel therapeutic approach to DN.

Rationale: Interleukin 22 (IL-22) is an epithelial survival cytokine that is at present being explored as therapeutic agents for acute and chronic liver injury. However, its molecular basis of protective activities remains poorly understood. Methods: Here we demonstrate that IL-22 inhibits the deteriorating metabolic states induced by stimuli in hepatocytes. Utilizing cell biological, molecular, and biochemical approaches, we provide evidence that IL-22 promotes oxidative phosphorylation (OXPHOS) and glycolysis and regulates the metabolic reprogramming related transcriptional responses. Results: IL-22 controls metabolic regulators and enzymes activity through the induction of AMP-activated protein kinase (AMPK), AKT and mammalian target of rapamycin (mTOR), thereby ameliorating mitochondrial dysfunction. The upstream effector lncRNA H19 also participates in the controlling of these metabolic processes in hepatocytes. Importantly, amelioration of liver injury by IL-22 through activation of metabolism relevant signaling and regulation of mitochondrial function are further demonstrated in cisplatin-induced liver injury and steatohepatitis. Conclusions: Collectively, our results reveal a novel mechanism underscoring the regulation of metabolic profiles of hepatocytes by IL-22 during liver injury, which might provide useful insights from the bench to the clinic in treating and preventing liver diseases.