Protein acetylation and related potential therapeutic strategies in kidney disease.

Kidney disease can be caused by various internal and external factors that have led to a continual increase in global deaths. Current treatment methods can alleviate but do not markedly prevent disease development. Further research on kidney disease has revealed the crucial function of epigenetics, especially acetylation, in the pathology and physiology of the kidney. Histone acetyltransferases (HATs), histone deacetylases (HDACs), and acetyllysine readers jointly regulate acetylation, thus affecting kidney physiological homoeostasis. Recent studies have shown that acetylation improves mechanisms and pathways involved in various types of nephropathy. The discovery and application of novel inhibitors and activators have further confirmed the important role of acetylation. In this review, we provide insights into the physiological process of acetylation and summarise its specific mechanisms and potential therapeutic effects on renal pathology.

Insulin-like growth factor binding protein 7 promotes acute kidney injury by alleviating poly ADP ribose polymerase 1 degradation.

The novel biomarker, insulin-like growth factor binding protein 7 (IGFBP7), is used clinically to predict different types of acute kidney injury (AKI) and has drawn significant attention as a urinary biomarker. However, as a secreted protein in the circulation of patients with AKI, it is unclear whether IGFBP7 acts as a key regulator in AKI progression, and if mechanisms underlying its upregulation still need to be determined. Here we found that IGFBP7 is highly expressed in the blood and urine of patients and mice with AKI, possibly via a c-Jun-dependent mechanism, and is positively correlated with kidney dysfunction. Global knockout of IGFBP7 ameliorated kidney dysfunction, inflammatory responses, and programmed cell death in murine models of cisplatin-, kidney ischemia/reperfusion-, and lipopolysaccharide-induced AKI. IGFBP7 mainly originated from kidney tubular epithelial cells. Conditional knockout of IGFBP7 from the kidney protected against AKI. By contrast, rescue of IGFBP7 expression in IGFBP7-knockout mice restored kidney damage and inflammation. IGFBP7 function was determined in vitro using recombinant IGFBP7 protein, IGFBP7 knockdown, or overexpression. Additionally, IGFBP7 was found to bind to poly [ADP-ribose] polymerase 1 (PARP1) and inhibit its degradation by antagonizing the E3 ubiquitin ligase ring finger protein 4 (RNF4). Thus, IGFBP7 in circulation acts as a biomarker and key mediator of AKI by inhibiting RNF4/PARP1-mediated tubular injury and inflammation. Hence, over-activation of the IGFBP7/PARP1 axis represents a promising target for AKI treatment.

Catalytic divergent synthesis of imidazoles via reaction condition-dependent [3 + 2] cyclization of TosMIC.

A base-catalyzed divergent synthesis of multisubstituted imidazoles through TosMIC-based [3 + 2] cyclization reaction has been developed. In the presence of ketenimines and tBuONa, 1,4,5-trisubstituted imidazoles were obtained. Nonetheless, in the absence of ketenimines, 1,4-disubstituted imidazole was produced through cyclodimerization of TosMIC.

DNA methylation of FTO promotes renal inflammation by enhancing m6A of PPAR-α in alcohol-induced kidney injury.

Alcohol consumption is one of the risk factors for kidney injury. The underlying mechanism of alcohol-induced kidney injury remains largely unknown. We previously found that the kidney in a mouse model of alcoholic kidney injury had severe inflammation. In this study, we found that the administration of alcohol was associated with the activation of NLRP3 inflammasomes and NF-κB signaling, and the production of pro-inflammatory cytokines. Whole-genome methylation sequencing (WGBS) showed that the DNA encoding fat mass and obesity-associated protein (FTO) was significantly methylated in the alcoholic kidney. This finding was confirmed with the bisulfite sequencing (BSP), which showed that alcohol increased DNA methylation of FTO in the kidney. Furthermore, inhibition of DNA methyltransferases (DNMTs) by 5-azacytidine (5-aza) reversed alcohol-induced kidney injury and decreased the mRNA and protein levels of FTO. Importantly, we found that FTO, the m6A demethylase, epigenetically modified peroxisome proliferator activated receptor-α (PPAR-α) in a YTH domain family 2 (YTHDF2)-dependent manner, which resulted in inflammation in alcoholic kidney injury models. In conclusion, our findings indicate that alcohol increases the methylation of PPAR-α m6A by FTO-mediated YTHDF2 epigenetic modification, which ultimately leads to the activation of NLRP3 inflammasomes and NF-κB-driven renal inflammation in the kidney. These findings may provide novel strategies for preventing and treating alcoholic kidney diseases.

Pyrazoline derivatives as tubulin polymerization inhibitors with one hit for Vascular Endothelial Growth Factor Receptor 2 inhibition.

In this work, to check the effect of the transposition of the rings in typical patterns, a series of pyrazoline derivatives 3a-3t bearing the characteristic 3,4,5-trimethoxy phenyl and thiophene moieties were synthesized and evaluated as tubulin polymerization inhibitors. Basically, as the concise output of our design, a majority of the synthesized compounds showed potency in inhibiting the tubulin polymerization. The top hit, 3q, exhibited potent anti-proliferation activity on cancer cell lines. It was comparable on tubulin-polymerization inhibition with the positive control Colchicine but lower toxic. The VEGFR2 inhibitory potency was introduced occasionally. The flow cytometry assay confirmed the apoptotic procedure and the confocal imaging revealed the tubulin-microtubule dynamics pattern. The anti-cancer mechanism of 3q was similar to Colchicine but not exactly the same on forming multi-polar spindles. The docking simulation visualized the possible binding patterns of 3q into tubulin and VEGFR2, respectively. The results inferred that further investigations on the transposition of the rings might lead to the improvement of tubulin polymerization inhibitory activity and the steadily introduction of the VEGFR2 inhibition.

LncRNA H19 promotes triple-negative breast cancer cells invasion and metastasis through the p53/TNFAIP8 pathway.

BACKGROUND: Long non-coding RNA H19 (lncRNA H19) has been implicated in tumorigenesis and metastasis of breast cancer through regulating epithelial to mesenchymal transition (EMT); however, the underlying mechanisms remain elusive. METHODS: LncRNA H19 and TNFAIP8 were identified by qRT-PCR and western blotting. CCK-8 assay, clone formation assay, transwell assay, and flow cytometry assay were performed to determine cell proliferation, migration, invasion and cell cycle of breast cancer respectively. Western blotting and immunohistochemistry (IHC) were utilized to evaluate the protein expression levels of p53, TNFAIP8, and marker proteins of EMT cascades in vivo. Dual luciferase reporter assay and RNA pull down assay were conducted to evaluate the interactions of lncRNA H19, p53 and TNFAIP8. RESULTS: The expression of lncRNA H19 and TNFAIP8 was up-regulated in breast cancer tissues and cell lines, especially in triple-negative breast cancer (TNBC). Functionally, knockdown of lncRNA H19 or TNFAIP8 coused the capacities of cell proliferation, migration, and invasion were suppressed, and cell cycle arrest was induced, as well as that the EMT markers were expressed abnormal. Mechanistically, lncRNA H19 antagonized p53 and increased expression of its target gene TNFAIP8 to promote EMT process. Furthermore, silencing of lncRNA H19 or TNFAIP8 also could inhibit tumorigenesis and lymph node metastases of MDA-MB-231 cells in xenograft nude mouse models. CONCLUSIONS: Our findings provide insight into a novel mechanism of lncRNA H19 in tumorigenesis and metastases of breast cancer and demonstrate H19/p53/TNFAIP8 axis as a promising therapeutic target for breast cancer, especially for TNBC.

RIPK1 inhibitor Cpd-71 attenuates renal dysfunction in cisplatin-treated mice via attenuating necroptosis, inflammation and oxidative stress.

Acute kidney injury (AKI) is a destructive clinical condition induced by multiple insults including ischemic reperfusion, nephrotoxic drugs and sepsis. It is characterized by a sudden decline in renal function, in addition to excessive inflammation, oxidative stress and programmed cell death of renal tubular epithelial cells. RIPK1-mediated necroptosis plays an important role in AKI. In the present study, we evaluated the treatment effects of Compound-71 (Cpd-71), a novel RIPK1 inhibitor, by comparing with Necrostatin-1 (Nec-1), a classic RIPK1 inhibitor, which has several drawbacks like the narrow structure-activity relationship (SAR) profile, moderate potency and non-ideal pharmacokinetic properties, in vivo and in vitro Our results showed that pretreatment of Cpd-71 attenuated cisplatin-induced renal injury, restored renal function and suppressed renal inflammation, oxidative stress and cell necroptosis. In addition, Cpd-71 inhibited renal damage while reducing the up-regulated serum creatinine (Cr) and blood urea nitrogen (BUN) levels in established AKI mice model. Consistently, we confirmed that Cpd-71 exhibited more effectively suppressive effect on cisplatin-induced renal tubular cell necroptosis than Nec-1, by physically binding to the allosteric type III ligand binding site of RIPK1, thereby reduced RIPK1 kinase activity, RIPK1/RIPK3 complex formation and phosphor-MLKL membrane translocation by molecular docking, Western blot, co-immunoprecipitation and cellular thermal shift assay (CETSA). Taken together, we currently showed that targeting RIPK1 with Cpd-71 may serve as a promising clinical candidate for AKI treatment.

Discovery of novel oxoindolin derivatives as atypical dual inhibitors for DNA Gyrase and FabH.

The antibacterial agents and therapies today are facing serious problems such as drug resistance. Introducing dual inhibiting effect is a valid approach to solve this trouble and bring advantages including wide adaptability, favorable safety and superiority of combination. We started from potential DNA Gyrase inhibitory backbone isatin to develop oxoindolin derivatives as atypical dual Gyrase (major) and FabH (assistant) inhibitors via a two-round screening. Aiming at blocking both duplication (Gyrase) and survival (FabH), most of synthesized compounds indicated potency against Gyrase and some of them inferred favorable inhibitory effect on FabH. The top hit I18 suggested comparable Gyrase inhibitory activity (IC50 = 0.025 µM) and antibacterial effect with the positive control Novobiocin (IC50 = 0.040 µM). FabH inhibitory activity (IC50 = 5.20 µM) was also successfully introduced. Docking simulation hinted possible important interacted residues and binding patterns for both target proteins. Adequate Structure-Activity Relation discussions provide the future orientations of modification. With high potency, low initial toxicity and dual inhibiting strategy, advanced compounds with therapeutic methods will be developed for clinical application.

[Wnt5a modulates vincristine resistance through PI3K/Akt/GSK3ß signaling pathway in human ovarian carcinoma SKOV3/VCR cells].

The aim of this study was to investigate the effect of Wnt5a on the vincristine (VCR) resistance in human ovarian carcinoma SKOV3 cells and its possible mechanism. The drug-resistant SKOV3/VCR cells were established by stepwise exposure to VCR, and then the SKOV3/VCR cells were stably transfected with specific shRNA interference plasmid vector targeting for Wnt5a. The mRNA expression level of Wnt5a was measured by RT-PCR. CCK-8 assay was used to detect the cell viability of SKOV3/VCR cells. The apoptosis was analyzed by flow cytometry. The protein expression levels of Wnt5a, MDR1, Survivin, ß-catenin, Akt, p-Akt(S473), GSK3ß and p-GSK3ß(Ser9) were detected by Western blot. The result showed that SKOV3/VCR cells had significantly higher protein expression levels of Wnt5a, MDR1, Survivin and ß-catenin, phosphorylation levels of Akt and GSK3ß, and mRNA expression level of Wnt5a, compared with SKOV3 cells (P < 0.05). WNT5A gene silencing significantly increased the sensitivity of SKOV3/VCR cells to VCR, the IC50 of VCR being decreased from 38.412 to 9.283 mg/L (P < 0.05), synergistically enhanced VCR-induced apoptosis of SKOV3/VCR cells (P < 0.05), down-regulated the protein expression levels of MDR1, ß-catenin and Survivin (P < 0.05), and inhibited phosphorylation of Akt and GSK3ß (P < 0.05). Meanwhile, LY294002 (PI3K inhibitor) decreased the protein expression levels of MDR1, ß-catenin and Survivin, as well as the phosphorylation levels of Akt and GSK3ß in SKOV3/VCR cells (P < 0.05). These results suggest that WNT5A gene silencing reverses VCR resistance in SKOV3/VCR cells possibly through blocking the PI3K/Akt/GSK3ß/ß-catenin signaling pathway, and thus down-regulating the protein expression levels of MDR1 and Survivin.

Madecassoside alleviates acute kidney injury by regulating JNK-mediated oxidative stress and programmed cell death.

BACKGROUND: Acute kidney injury (AKI) has high morbidity and mortality, which is manifested by inflammation and apoptosis. Effective treatment methods for AKI are currently lacking. OBJECTIVE: This study demonstrated the protecting effects of Madecassoside (MA) in the cisplatin- and hypoxia-reoxygenation-induced renal tubular epithelial cells in vitro and AKI mice in vivo. METHODS: In vivo AKI mouse models were established by inducing them with cisplatin and renal ischemia-reperfusion. In vitro injury models of mouse renal tubular epithelial cells were established by inducing them with cisplatin and hypoxia and reoxygenation, respectively. The mechanism of MA effects was further explored using molecular docking and RNA-sequencing. RESULTS: MA could significantly reduce kidney injury in the cisplatin-and renal ischemia-reperfusion (IRI)-induced AKI. Further validation in the two cellular models also showed that MA had protect effects. MA can alleviate AKI in vitro and in vivo by inhibiting inflammation, cell apoptosis, and oxidative stress. MA exhibited high permeability across the Caco-2 cell, can enter cells directly. Through RNA-seq and molecular docking analysis, this study further demonstrated that MA inhibits its activity by directly binding to JNK kinase, thereby inhibiting c-JUN mediated cell apoptosis and improving AKI. In addition, MA has better renal protective effects compared to curcumin and JNK inhibitor SP600125. CONCLUSION: The results demonstrate that MA might be a potential drug for the treatment of AKI and act through the JNK/c-JUN signaling pathway.

MiR-199a-5p enhances neuronal differentiation of neural stem cells and promotes neurogenesis by targeting Cav-1 after cerebral ischemia.

AIMS: MicroRNAs (miRs) are involved in endogenous neurogenesis, enhancing of which has been regarded as a potential therapeutic strategy for ischemic stroke treatment; however, whether miR-199a-5p mediates postischemic neurogenesis remains unclear. This study aims to investigate the proneurogenesis effects of miR-199a-5p and its possible mechanism after ischemic stroke. METHODS: Neural stem cells (NSCs) were transfected using Lipofectamine 3000 reagent, and the differentiation of NSCs was evaluated by immunofluorescence and Western blotting. Dual-luciferase reporter assay was performed to verify the target gene of miR-199a-5p. MiR-199a-5p agomir/antagomir were injected intracerebroventricularly. The sensorimotor functions were evaluated by neurobehavioral tests, infarct volume was measured by toluidine blue staining, neurogenesis was detected by immunofluorescence assay, and the protein levels of neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP), caveolin-1 (Cav-1), vascular endothelial growth factor (VEGF), and brain-derived neurotrophic factor (BDNF) were measured by Western blotting. RESULTS: MiR-199a-5p mimic enhanced neuronal differentiation and inhibited astrocyte differentiation of NSCs, while a miR-199a-5p inhibitor induced the opposite effects, which can be reversed by Cav-1 siRNA. Cav-1 was through the dual-luciferase reporter assay confirmed as a target gene of miR-199a-5p. miR-199a-5p agomir in rat stroke models manifested multiple benefits, such as improving neurological deficits, reducing infarct volume, promoting neurogenesis, inhibiting Cav-1, and increasing VEGF and BDNF, which was reversed by the miR-199a-5p antagomir. CONCLUSION: MiR-199a-5p may target and inhibit Cav-1 to enhance neurogenesis and thus promote functional recovery after cerebral ischemia. These findings indicate that miR-199a-5p is a promising target for the treatment of ischemic stroke.

Novel insights into STAT3 in renal diseases.

Signal transducer and activator of transcription 3 (STAT3) is a cell-signal transcription factor that has attracted considerable attention in recent years. The stimulation of cytokines and growth factors can result in the transcription of a wide range of genes that are crucial for several cellular biological processes involved in pro- and anti-inflammatory responses. STAT3 has attracted considerable interest as a result of a recent upsurge in study because of their role in directing the innate immune response and sustaining inflammatory pathways, which is a key feature in the pathogenesis of many diseases, including renal disorders. Several pathological conditions which may involve STAT3 include diabetic nephropathy, acute kidney injury, lupus nephritis, polycystic kidney disease, and renal cell carcinoma. STAT3 is expressed in various renal tissues under these pathological conditions. To better understand the role of STAT3 in the kidney and provide a theoretical foundation for STAT3-targeted therapy for renal disorders, this review covers the current work on the activities of STAT3 and its mechanisms in the pathophysiological processes of various types of renal diseases.

Two adenovirus serotype 3 outbreaks associated with febrile respiratory disease and pharyngoconjunctival fever in children under 15 years of age in Hangzhou, China, during 2011.

Adenovirus serotype 3 and 7 outbreaks have occurred periodically in northern, eastern, and southern China since 1955, but there has been no report since the adenovirus serotype 7 outbreak first occurred in Hangzhou, China, in 1991. Here we explored the epidemiology and etiology of two adenovirus serotype 3 outbreaks in Hangzhou in 2011. One acute respiratory outbreak was found in Chun'an County, where a total of 371 cases were confirmed in 5 of 23 towns from 4 to 31 May 2011. The outbreak affected 18.57% (13/70) of schools and 14.49% (90/621) of classes. The incidence was 5.18% (371/7,163). The population was distributed among individuals ages 7 to 15 years. No parents or teachers were infected. Another pharyngoconjunctival fever outbreak was discovered in the Chenjinglun Swimming Center located in the Xihu District between 1 and 15 July 2011. A total of 134 cases were confirmed in 900 amateur swimmers, with an incidence of 14.89% (134/900). The ages ranged from 4 to 9 years. The two outbreaks had no severe complications or death. The viruses in 66.67% (10/15) of throat swabs from children with acute respiratory infections and 100% (10/10) of the swabs from children with pharyngoconjunctival fever were confirmed to be adenovirus serotype 3 with 100% homology by PCR. Of these samples, 60.0% (12/20) had a classical characteristic cytopathic effect, presented as grape-like clusters at 72 h after infection in HEp-2 cells. In conclusion, the acute respiratory infection and pharyngoconjunctival fever outbreak in Hangzhou were caused by the completely homologous type 3 adenovirus in subgenus B. Moreover, these outbreaks demonstrated rapid transmission rates, possibly due to close contact and droplet transmission.

Direct electrochemistry and electrocatalytic behavior of hemoglobin entrapped in Ag@C nanocables/gold nanoparticles nanocomposites film.

Direct electrochemistry of hemoglobin (Hb) was successfully fabricated by immobilizing Hb on the nanocomposites containing of Ag@C nanocables and Au nanoparticles (AuNPs) modified glassy carbon electrode (GCE). The immobilized Hb retained its biological activity and shown high catalytic activities to the reduction of H2O2 by circular dicroism (CD) spectrum, fourier transform infrared (FT-IR) spectrum and cyclic voltammetry (CV). Experimental conditions such as scan rate and pH Value were studied and optimized. The results indicated that the resulting biosensor are linear to the concentrations of H2O2 in the ranges of 6.67 x 10(-7)-2.40 x 10(5) M, and the detection limit is 2.02 x 10(-7) M. The electrochemical biosensor has also high stability and good reproducibility.

A fluorescent probe derived from Berberrubine for detecting hydrogen polysulfide in food samples.

In this work, we chose the fluorophore Berberrubine to develop a selective probe for hydrogen polysulfide (H2Sn), and applied it into the detection in both food samples and living cells. The developed probe, HER9SS, suggested practical steadiness and serviceability, especially for multi-scene detection. The detecting system was stable in relatively wide pH (7.0-11.0) and temperature (25-45 °C) ranges. Both the storage of BER9SS in solid or in solution could maintain the steadiness over 7 d. BER9SS also indicated advantages including rapid response (within 15 min), high sensitivity (LOD = 0.02 µM; LOQ = 0.01 µM), long linear range (0-15.0 equivalent) and high selectivity among competing analytes. The recovery ranging in 95.23% - 104.8% in the applications in food sources samples (including water and plants) and food samples inferred the practical potential of BER9SS. In biological imaging, BER9SS could achieve both the dose-dependent monitoring and the ß-lapachone-induced generation of H2Sn. Therefore, the information in this work might be useful for the development of fluorescent probes from natural products for multi-scene applications in future, especially with the corresponding attentions on the practicability and serviceability.

A berberrubine-derived fluorescent probe for hydrazine and its practical application in water and food samples.

In this work, we attempted to develop a fluorescent probe for hydrazine in real samples. Accordingly, we designed BER9-HZ to fulfill the set rules as solubility, anti-interference capability and functional compatibility. The selected reporting group BER9 dissolved 100% within 10 min, which indicated much better solubility than Berberine. The 615 nm reporting signal was in the Near-Infrared region. BER9-HZ presented advantages including wide linear range (0-20 equivalent), high sensitivity (detection limit 0.076 µM), steadiness (pH 7.0-13.0, temperature 25-45 °C), rapid response (within 20 min) and high selectivity in both independent and co-existing systems. Significantly, BER9-HZ could work steadily in real environmental, plant and food samples, thus be used in the detection of hydrazine (directly incubated or pre-treated with real sample) in living cells. Therefore, this work marched one step further to the systematic managing of hydrazine in real samples, and raised useful information for future investigations on Nitrogen circulation.

Smad3-Targeted Therapy Protects against Cisplatin-Induced AKI by Attenuating Programmed Cell Death and Inflammation via a NOX4-Dependent Mechanism.

BACKGROUND: Transforming growth factor-ß (TGF-ß)/Smad signaling is the central mediator in renal fibrosis, yet its functional role in acute kidney injury (AKI) is not fully understood. Recent evidence showed that TGF-ß/Smad3 may be involved in the pathogenesis of AKI, but its functional role and mechanism of action in cisplatin-induced AKI are unclear. OBJECTIVES: Demonstrating that Smad3 may play certain roles in cisplatin nephropathy due to its potential effect on programmed cell death and inflammation. METHODS: Here, we established a cisplatin-induced AKI mouse model with Smad3 knockout mice and created stable in vitro models with Smad3 knockdown tubular epithelial cells. In addition, we tested the potential of Smad3-targeted therapy using 2 in vivo protocols - lentivirus-mediated Smad3 silencing in vivo and use of naringenin, a monomer used in traditional Chinese medicine and a natural inhibitor of Smad3. RESULTS: Disruption of Smad3 attenuated cisplatin-induced kidney injury, inflammation, and NADPH oxidase 4-dependent oxidative stress. We found that Smad3-targeted therapy protected against loss of renal function and alleviated apoptosis, RIPK-mediated necroptosis, renal inflammation, and oxidative stress in cisplatin nephropathy. CONCLUSIONS: These findings show that Smad3 promotes cisplatin-induced AKI and Smad3-targeted therapy protects against this pathological process. These findings have substantial clinical relevance, as they suggest a therapeutic target for AKI.

The Efficacy of Percutaneous Patent Foramen Ovale Closure on Migraine: a Meta-Analysis of Randomized Controlled Trials and Observational Studies.

OBJECTIVES: Whether patent foramen ovale (PFO) closure is effective on migraine is controversial. This article was aimed at assessing the efficacy of PFO closure on migraine based on randomized controlled trials (RCTs) and observational studies. METHODS: We searched PubMed, Embase, and Cochrane databases up to October 2020 evaluating PFO closure versus control in patients with migraine, then conducted a meta-analysis of all RCTs and observational studies, respectively. The main outcomes were (1) respond rate: complete cessation of migraine; (2) reduction in the frequency of migraine attacks per month; and (3) reduction in migraine days per month. RESULTS: Seven studies (3 RCTs and 4 observational studies), containing 887 migraine patients, were identified. (1) The respond rate of PFO closure on migraine was significantly higher than control group both in RCT subgroup and observational studies subgroup (OR 3.86, 95% CI 1.35-11.04, P = 0.01 in RCTs; OR 8.28, 95% CI 2.31-29.67, P = 0.001 in observational studies). (2) Reduction in frequency of migraine attacks was higher in PFO closure group compared with control group in the RCT subgroup analysis (mean difference (MD) = 0.57, 95% CI 0.23-0.90, P = 0.0009). (3) Reduction in migraine days was also higher in PFO closure group compared with control group in the RCT subgroup analysis (MD = 1.33, 95% CI 0.35-2.31, P = 0.008). CONCLUSIONS: PFO closure might be suitable for migraine patients, especially for migraine with aura, by cessation of migraine headaches or reducing migraine attacks and migraine days.

Stereoselective Access to Spirooxindoles and Bisoxindoles Through Organocatalyzed Asymmetric Divergent Transformations of Isatin-derived MBH Carbonates.

An interesting ß-isoquinidine catalyzed divergent reaction was developed to produce either spirocyclopentene oxindoles, spirocyclopentadiene oxindoles or bisoxindoles in a high enantioselective fashion. The utility of this protocol was demonstrated by the versatile transformations of the products. This work not only represents the first highly stereoselective intermolecular catalytic asymmetric allylic alkylation reaction between two isatin-derived MBH carbonate molecules but also constitutes a rare example of isatin-derived MBH carbonate-based enantioselective and α-regioselective [3+2] cycloaddition reactions.

Gypenoside XLIX protects against acute kidney injury by suppressing IGFBP7/IGF1R-mediated programmed cell death and inflammation.

BACKGROUND: Acute kidney injury (AKI), characterised by excessive inflammatory cell recruitment and programmed cell death, has a high morbidity and mortality; however, effective and specific therapies for AKI are still lacking. OBJECTIVE: This study aimed to evaluate the renoprotective effects of gypenoside XLIX (Gyp XLIX) in AKI. METHODS: The protective effects of Gyp XLIX were tested in two AKI mouse models established using male C57BL/6 mice (aged 6-8 weeks) by a single intraperitoneal injection of cisplatin (20 mg/kg) or renal ischemia-reperfusion for 40 min. Gyp XLIX was administered intraperitoneally before cisplatin administration or renal ischemia-reperfusion. Renal function, tubular injury, renal inflammation and programmed cell death were evaluated. In addition, the renoprotective effects of Gyp XLIX were also evaluated in cisplatin- or hypoxia-treated tubular epithelial cells. The mechanisms underlying these effects were then explored using RNA sequencing. RESULTS: In vivo, Gyp XLIX substantially suppressed the increase in serum creatinine and blood urea nitrogen levels. Moreover, tubular damage was alleviated by Gyp XLIX as shown by periodic acid-Schiff staining, electron microscopy and molecular analysis of KIM-1. Consistently, we found that Gyp XLIX suppressed renal necroptosis though the RIPK1/RIPK3/MLKL pathway. The anti-inflammatory and antinecroptotic effects were further confirmed in vitro. Mechanistically, RNA sequencing showed that Gyp XLIX markedly suppressed the levels of IGF binding protein 7 (IGFBP7). Co-immunoprecipitation and western blot analysis further showed that Gyp XLIX reduced the binding of IGFBP7 to IGF1 receptor (IGF1R). Additionally, picropodophyllin, an inhibitor of IGF1R, abrogated the therapeutic effects of Gyp XLIX on cisplatin-induced renal cell injury; this finding indicated that Gyp XLIX may function by activating IGF1R-mediated downstream signalling Additionally, we also detected the metabolic distribution of Gyp XLIX after injection; Gyp XLIX had a high concentration in the kidney and exhibited a long retention time. These findings may shed light on the application of Gyp XLIX for AKI treatment clinically. CONCLUSION: Gyp XLIX may serve as a potential therapeutic agent for AKI treatment via IGFBP7/ IGF1R-dependent mechanisms.