Multi-omics analysis reveals the functional transcription and potential translation of enhancers.

Enhancer can transcribe RNAs, however, most of them were neglected in traditional RNA-seq analysis workflow. Here, we developed a Pipeline for Enhancer Transcription (PET, http://fun-science.club/PET) for quantifying enhancer RNAs (eRNAs) from RNA-seq. By applying this pipeline on lung cancer samples and cell lines, we showed that the transcribed enhancers are enriched with histone marks and transcription factor motifs (JUNB, Hand1-Tcf3 and GATA4). By training a machine learning model, we demonstrate that enhancers can predict prognosis better than their nearby genes. Integrating the Hi-C, ChIP-seq and RNA-seq data, we observe that transcribed enhancers associate with cancer hallmarks or oncogenes, among which LcsMYC-1 (Lung cancer-specific MYC eRNA-1) potentially supports MYC expression. Surprisingly, a significant proportion of transcribed enhancers contain small protein-coding open reading frames (sORFs) and can be translated into microproteins. Our study provides a computational method for eRNA quantification and deepens our understandings of the DNA, RNA and protein nature of enhancers.

Potent Therapy and Transcriptional Profile of Combined Erythropoietin-Derived Peptide Cyclic Helix B Surface Peptide and Caspase-3 siRNA against Kidney Ischemia/Reperfusion Injury in Mice.

Cause-specific treatment and timely diagnosis are still not available for acute kidney injury (AKI) apart from supportive therapy and serum creatinine measurement. A novel erythropoietin-derived cyclic helix B surface peptide (CHBP) protects kidneys against AKI with different causes, but the underlying mechanism is not fully defined. Herein, we investigated the transcriptional profile of renoprotection induced by CHBP and its potential synergistic effects with siRNA targeting caspase-3, an executing enzyme of apoptosis and inflammation (CASP3siRNA), on ischemia/reperfusion (IR)-induced AKI. Utilizing a mouse model with 30-minute renal bilateral ischemia and 48-hour reperfusion, the renoprotection of CHBP or CASP3siRNA was demonstrated in renal function and structure, active caspase-3 and HMGB1 expression. Combined treatment of CHBP and CASP3siRNA further preserved kidney structure and reduced active caspase-3 and HMGB1. Furthermore, differentially expressed genes (DEGs) were identified with fold change >1.414 and P < 0.05. In IR kidneys, 281 DEGs induced by CHBP were mainly involved in promoting cell division and improving cellular function and metabolism (upregulated signal transducer and activator of transcription 5B and solute carrier family 22 member 7). The additional administration of CASP3siRNA caused 504 and 418 DEGs in IR + CHBP kidneys with or without negative control small-interfering RNA, with 37 genes in common. These DEGs were associated with modulated apoptosis and inflammation (upregulated BCL6, SLPI, and SERPINA3M) as well as immunity, injury, and microvascular homeostasis (upregulated complement factor H and GREM1 and downregulated ANGPTL2). This proof-of-effect study indicated the potent renoprotection of CASP3siRNA upon CHBP at the early stage of IR-induced AKI. Underlying genes, BCL6, SLPI, SERPINA3M, GREM1, and ANGPTL2, might be potential new biomarkers for clinical applications. SIGNIFICANCE STATEMENT: It is imperative to explore new strategies of cause-specific treatment and timely diagnosis for acute kidney injury (AKI). CHBP and CASP3siRNA synergistically protected kidney structure after 48-hour ischemia/reperfusion-induced AKI with reduced injury mediators CASP3 and high mobility group box 1. CHBP upregulated cell division-, function-, and metabolism-related genes, whereas CASP3siRNA further regulated immune response- and tissue homeostasis-associated genes. Combined CHBP and CASP3siRNA might be a potent and specific treatment for AKI, and certain dysregulated genes secretory leukocyte peptidase inhibitor and SERPINA3M could facilitate timely diagnosis.

Effect of rapamycin on the level of autophagy in rats with early heart failure.

OBJECTIVES: Heart failure (HF) progression can be prevented by an inhibitor of the mammalian target of rapamycin and an autophagy enhancer rapamycin. This current study aimed to investigate the effect of rapamycin on HF progression and myocardial cells apoptosis. METHODS: HF rats were injected with low-, middle-, and high-dose rapamycin. Echocardiography, hematoxylin-eosin staining, plasma brain natriuretic peptide, myocardial cells apoptosis, and Akt activation in rapamycin-treated rats were detected. RESULTS: HF rats showed reduced cardiac functions, destructive pathological changes in the myocardium, enhanced Akt activation and myocardial cells apoptosis. However, rapamycin reversed all the changes in a dose-dependent manner. Cardiac functions were enhanced by rapamycin. Myocardial cells apoptotic percentage, Akt expression, and pathological changes of the myocardium in HF rats were inhibited by rapamycin administration. CONCLUSIONS: Rapamycin protected against myocardial hypertrophy and myocardial cells apoptosis in HF rats in a dose-dependent manner.

Role of angiotensin-converting enzyme insertion/deletion polymorphism in sudden cardiac arrest.

OBJECTIVE: This study aimed to investigate the relationship between angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and to understand sudden cardiac arrest (SCA) in the Chinese population. METHODS: In this study, 232 patients were divided into the SCA group and the coronary disease group with coronary disease, but no SCA occurred during the treatment period. After comparing the genotype frequencies of the two groups, all patients were further divided into three groups as the II homozygotes, ID heterozygotes, and DD homozygotes to investigate the relationship in ACE I/D polymorphism and other risk factors of SCA. RESULTS: The frequencies of DD genotype in the SCA group were significantly higher than the coronary disease group, as well as the D allele frequencies in the SCA group were high when compared with the coronary disease group. According to the genotypes of the ACE I/D polymorphism, the distribution of patients' characteristics had no significant differences among all the characteristics. Both, the patients who survived SCA, with II genotype and the ones who died of SCA, with DD genotype had significant higher percentages. CONCLUSION: The DD genotype was associated with a higher prevalence of SCA and might be a risk factor of survival rate in sudden cardiac death.

Downregulation of Nedd4L predicts poor prognosis, promotes tumor growth and inhibits MAPK/ERK signal pathway in hepatocellular carcinoma.

Accumulating evidence indicates that the neural precursor cell-expressed, developmentally downregulated 4-like (Nedd4L) related with some tumor progression pathways and was found abnormally expressed in several kinds of solid cancers. However, the role and mechanism of Nedd4L in HCC remain unknown. This study was to assess the role of Nedd4L in HCC tumorigenesis and prognosis. The real-time quantitative RT-PCR and immunohistochemistry results revealed that Nedd4L was downregulated in HCC tissues compared to corresponding peri-noncancerous tissue, and HCC patients with low expression of Nedd4L exhibited poor prognosis assessed by Kaplan-Meier and Cox regression analysis in 78 HCC patients. Furthermore, knockdown of Nedd4L could significantly promote proliferation of HCC cells by CCK-8 and colony formation assays in vitro; whereas ectopic expression of Nedd4L resulted in attenuating proliferation in vitro and tumor growth in vivc determined by nude mice xenografts model. Mechanically, Nedd4L could phosphorylate ERK1/2 and regulate genes related with apoptosis. Collectively, Nedd4L plays a tumor suppressive role in HCC, possibly through triggering MAPK/ERK-mediated apoptosis, and Nedd4L downregulation may be a potential prognostic biomarker as well as a therapeutic target for HCC.

Effects of vagus nerve stimulation on cognitive functioning in rats with cerebral ischemia reperfusion.

BACKGROUND: Vagus nerve stimulation (VNS) has become the most common non-pharmacological treatment for intractable drug-resistant epilepsy. However, the contribution of VNS to neurological rehabilitation following stroke has not been thoroughly examined. Therefore, we investigated the specific role of acute VNS in the recovery of cognitive functioning and the possible mechanisms involved using a cerebral ischemia/reperfusion (I/R) injury model in rats. METHODS: The I/R-related injury was modeled using occlusion and reperfusion of the middle cerebral artery (MCAO/R) in Sprague-Dawley rats. VNS was concurrently applied to the vagus nerve using a stimulation intensity of 1 mA at a fixed frequency of 20 Hz with a 0.4-ms bipolar pulse width. The stimulation duration and inter-train interval were both 3 s. Next, Morris water maze and shuttle-box behavioral experiments were conducted to assess the effects of VNS on the recovery of learning, memory, and inhibitory avoidance following I/R injury. Intracerebroventricular injection of N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4), a selective neurotoxin for noradrenergic neurons, was used to evaluate the role of norepinephrine (NE) as a mediator of therapeutic effects of VNS on cognitive recovery. RESULTS: Compared with the MCAO/R group, the VNS+MCAO/R group had improved spatial memory as indicated by swimming path lengths and escape latencies in the Morris water maze, and fear memory, as indicated by the avoidance conditioned response rate, mean shock duration, and avoidance time in shuttle-box behavior experiments. Compared with the VNS+MCAO/R group, the DSP-4+VNS+MCAO/R group, which had reduced NE levels in cortical and hippocampal brain regions, showed a reversal of the VNS-induced benefits on spatial and fear memory performance. CONCLUSIONS: VNS improves spatial and fear memory in a rat model of MCAO/R injury. However, a reduction in NE from the administration of DSP-4 blocks these protective effects, suggesting that NE may contribute to the influence exhibited by VNS on memory performance in rats with cerebral I/R-related injury.

Human embryonic mesenchymal stem cells alleviate pathologic changes of MRL/Lpr mice by regulating Th7 cell differentiation.

Recent evidence indicates that mesenchymal stem cells (MSC) derived from early embryonic tissues have better therapeutic ability as compared with adult tissue-derived stem cells. In the present study, we transplanted human early embryonic MSC (hMSC) into MRL/Lpr mice via tail vein injection to observe the therapeutic efficacy of hMSC and their impact on T helper 17 (Th17) cell differentiation in MRL/Lpr mice. Animals in hMSC treatment group received hMSC (1 × 106/200 µL) via the tail vein at the age of 16 and 19 weeks. We found that hMSC treatment prolonged the survival of MRL/Lpr mice without inducing tumorigenesis, reduced urine protein, and alleviated the renal pathologic changes. In addition, it reduced the proportion of Th17 cells in the spleen of MRL/Lpr mice and the serum interleukin 17 (IL-17) concentration. Our in vitro experiment also demonstrated that hMSC could secrete Th17 differentiation-related cytokines of PGE2, IL-10 and TGF-ß, and IFN-γ stimulation up-regulated the secretion of these immune regulating factors. The results of the present study suggest that hMSC therapy could alleviate systemic and local renal lesions in MRL/Lpr mice, probably by secreting immune regulating factors and regulating Th17 cell differentiation in MRL/Lpr mice.

Hypoxia-induced TRPM7 promotes glycolytic metabolism and progression in hepatocellular carcinoma.

BACKGROUND: Hypoxia disrupts glucose metabolism in hepatocellular carcinoma (HCC). Transient receptor potential cation channel, subfamily M, member 7 (TRPM7) plays an ontogenetic role. Thus, we aimed to explore the regulation of TRPM7 by hypoxia-induced factor (HIF) and its underlying mechanisms in HCC. METHODS: hypoxia was induced in multiple HCC cells using 1% O2 or CoCl2 treatment, and subsequently blocked using siRNAs targeting HIF-1α or HIF-2α as well as a HIF-1α protein synthesis inhibitor. The levels of HIF-1α and TRPM7 were assessed using quantitative PCR (qPCR) and Western blot analysis. Chromatin immunoprecipitation (ChIP) and luciferase assays were performed to observe the regulation of TRPM7 promoter regions by HIF-1α. A PCR array was utilized to screen glucose metabolism-related enzymes in HEK293 cells overexpressing TRPM7 induced by tetracycline, and then verified in TRPM7-overexpressed huh7 cells. Finally, CCK-8, transwell, scratch and tumor formation experiments in nude mice were conducted to examine the effect of TRPM7 on proliferation and metastasis in HCC. RESULTS: Exposure to hypoxia led to increase the levels of TRPM7 and HIF-1α in HCC cells, which were inhibited by HIF-1α siRNA or enhanced by HIF-1α overexpression. HIF-1α directly bound to two hypoxia response elements (HREs) in the TRPM7 promoter. Several glycolytic metabolism-related enzymes, were simultaneously upregulated in HEK293 and huh7 cells overexpressing TRPM7 during hypoxia. In vitro and in vivo experiments demonstrated that TRPM7 promoted the proliferation and metastasis of HCC cells. CONCLUSIONS: TRPM7 was directly transcriptionally regulated by HIF-1α, leading to glycolytic metabolic reprogramming and the promotion of HCC proliferation and metastasis in vitro and in vivo. Our findings suggest that TRPM7 might be a potential diagnostic indicator and therapeutic target for HCC.

Protective effects of HBSP on ischemia reperfusion and cyclosporine a induced renal injury.

Ischemia reperfusion (IR) and cyclosporine A (CsA) injuries are unavoidable in kidney transplantation and are associated with allograft dysfunction. Herein, the effect and mechanism of a novel tissue protective peptide, helix B surface peptide (HBSP) derived from erythropoietin, were investigated in a rat model. The right kidney was subjected to 45 min ischemia, followed by left nephrectomy and 2-week reperfusion, with or without daily treatment of CsA 25 mg/kg and/or HBSP 8 nmol/kg. Blood urea nitrogen was increased by CsA but decreased by HBSP at 1 week and 2 weeks, while the same changes were revealed in urinary protein/creatinine only at 2 weeks. HBSP also significantly ameliorated tubulointerstitial damage and interstitial fibrosis, which were gradually increased by IR and CsA. In addition, apoptotic cells, infiltrated inflammatory cells, and active caspase-3+ cells were greatly reduced by HBSP in the both IR and IR + CsA groups. The 17 kD active caspase-3 protein was decreased by HBSP in the IR and IR + CsA kidneys, with decreased mRNA only in the IR + CsA kidneys. Taken together, it has been demonstrated, for the first time, that HBSP effectively improved renal function and tissue damage caused by IR and/or CsA, which might be through reducing caspase-3 activation and synthesis, apoptosis, and inflammation.

Inhibition of microRNA-19a-3p alleviates the neuropathic pain (NP) in rats after chronic constriction injury (CCI) via targeting KLF7.

BACKGROUND/PURPOSE: Neuropathic pain(NP) is derived from the dysfunctions of nerve system. The current research is to explore the impact and mechanism of miR-19a-3p in neuropathic pain in rats. METHODS: The NP was induced through the chronic constriction injury (CCI) surgery in rats. The pro-inflammatory factors (IL-1ß, IL-6, TNF-α) in spinal cord tissues from rats were measured using Elisa kits. Moreover, the different levels of thermal hyperalgesia and mechanical allodynia in rats were examined through paw withdrawal latency (PWL) and paw withdrawal threshold (PWT). To investigate into the role of miR-19a-3p and KLF7 in NP of rats, the knockdown of miR-19a-3p alone or along with KLF7 downregulation in rats were achieved through lentivirus injection. The miR-19a-3p and KLF7 expression in spinal cord of rats on Day 3,7,14 after CCI were detected using RT-qPCR. The protein expression of KLF7 were measured by Western blot. Bioinformatics and luciferase assays were used for the prediction and verification of bindings between KLF7 and miR-19a-3p. RESULTS: CCI surgery caused neuropathic pain in rats with the levels of inflammatory cytokines increased and PWL and PWT decreased. Moreover, miR-19a-3p expression was increased while the protein and mRNA levels were decreased in spinal cord tissues in rats after CCI surgery. In rat microglial cells, miR-19a-3p downregulation could promote the KLF7 in both mRNA and protein expression. In spinal cord tissues of rats, the inhibition of miR-19a-3p enhanced the KLF7 expression. Furthermore, miR-19a-3p downregulation suppressed the IL-1ß, IL-6 and TNF-α concentrations, and could decrease the NP but inhibition of KLF7 could partially reverse this in CCI rats. CONCLUSION: miR-19a-3p inhibition may alleviate NP via KLF7 in CCI rats.

H2O as the Hydrogen Donor: Stereo-Selective Synthesis of E- and Z-Alkenes by Palladium-Catalyzed Semihydrogenation of Alkynes.

It is very desirable to develop a facile controllable method for selective semihydrogenation of alkynes to alkenes with a cheap and safe hydrogen donor but remains a big challenge. H2O is one of the best choices of the transfer hydrogenation agent of the world, and the development of methods for synthesizing E- and Z-alkenes using H2O as the hydrogen source is worthwhile. In this article, a palladium-catalyzed synthesis of E- and Z-alkenes from alkynes using H2O as the hydrogenation agent was reported. The use of di-tert-butylphosphinous chloride (t-Bu2PCl) and triethanolamine/sodium acetate (TEOA/NaOAc) was essential for the stereo-selective semihydrogenation of alkynes. The general applicability of this procedure was highlighted by the synthesis of more than 48 alkenes, with good yields and high stereoselectivities.

Neuroprotective Strategies for Stroke by Natural Products: Advances and Perspectives.

Cerebral ischemic stroke is a disease with high prevalence and incidence. Its management focuses on rapid reperfusion with intravenous thrombolysis and endovascular thrombectomy. Both therapeutic strategies reduce disability, but the therapy time window is short, and the risk of bleeding is high. Natural products (NPs) have played a key role in drug discovery, especially for cancer and infectious diseases. However, they have made little progress in clinical translation and pose challenges to the treatment of stroke. Recently, with the investigation of precise mechanisms in cerebral ischemic stroke and the technological development of NP-based drug discovery, NPs are addressing these challenges and opening up new opportunities in cerebral stroke. Thus, in this review, we first summarize the structure and function of diverse NPs, including flavonoids, phenols, terpenes, lactones, quinones, alkaloids, and glycosides. Then we propose the comprehensive neuroprotective mechanism of NPs in cerebral ischemic stroke, which involves complex cascade processes of oxidative stress, mitochondrial damage, apoptosis or ferroptosis-related cell death, inflammatory response, and disruption of the blood-brain barrier (BBB). Overall, we stress the neuroprotective effect of NPs and their mechanism on cerebral ischemic stroke for a better understanding of the advances and perspective in NPs application that may provide a rationale for the development of innovative therapeutic regimens in ischemic stroke.

Properties and functions of KATP during mouse perinatal development.

BACKGROUND: Prevailing data suggest that ATP-sensitive potassium channels (K(ATP)) contribute to a surprising resistance to hypoxia in mammalian embryos, thus we aimed to characterize the developmental changes of K(ATP) channels in murine fetal ventricular cardiomyocytes. METHODS: Patch clamp was applied to investigate the functions of K(ATP). RT-PCR, Western blot were used to further characterize the molecular properties of K(ATP) channels. RESULTS: Similar K(ATP) current density was detected in ventricular cardiomyocytes of late development stage (LDS) and early development stage (EDS). Molecular-biological study revealed the upregulation of Kir6.1/SUR2A in membrane and Kir6.2 remained constant during development. Kir6.1, Kir6.2, and SUR1 were detectable in the mitochondria without marked difference between EDS and LDS. Acute hypoxia-ischemia led to cessation of APs in 62.5% of tested EDS cells and no APs cessation was observed in LDS cells. SarcK(ATP) blocker glibenclamide rescued 47% of EDS cells but converted 42.8% of LDS cells to APs cessations under hypoxia-ischemic condition. MitoK(ATP) blocker 5-HD did not significantly influence the response to acute hypoxia-ischemia at either EDS or LDS. In summary, sarcK(ATP) played distinct functional roles under acute hypoxia-ischemic condition in EDS and LDS fetal ventricular cardiomyocytes, with developmental changes in sarcK(ATP) subunits. MitoK(ATP) were not significantly involved in the response of fetal cardiomyocytes to acute hypoxia-ischemia and no developmental changes of K(ATP) subunits were found in mitochondria.

Hypoxia-induced RNASEH2A limits activation of cGAS-STING signaling in HCC and predicts poor prognosis.

BACKGROUND: Hypoxia is a hallmark of solid cancers, including hepatocellular carcinoma (HCC). There is scarce information about how hypoxia avoids immunologic stress and maintains a cancer-promoting microenvironment. METHODS: The Cancer Genome Atlas, RNA-seq data, and Oncomine database were used to discover the correlation of RNASEH2A with tumor progression; then expression of RNASEH2A mRNA and protein were detected in HCC tissues and cells subjected to hypoxia or with the treatment of CoCl2 via real-time quantitative polymerase chain reaction and immunochemistry assays. Finally, the effect of RNASEH2A on cell proliferation and the involved signaling pathway was explored further. RESULTS: RNASEH2A was positively correlated with tumor grade, size, vascular invasion, and poor prognosis. The expression of RNASEH2A mRNA and protein were increased and dependent on hypoxia-inducible factor 2α in HCC tissues and cell lines. Knockout of RNASEH2A in HCC cells greatly reduced cell proliferation and induced the transcription of multiple cGAS-STING (cyclic GMP-AMP synthase-stimulator of interferon genes) targeted type 1 interferon-related genes, including IFIT1, USP18, and CXCL10, which suggests knockout of RNASEH2A may produce immunologic stress and tumor suppressive effects. CONCLUSIONS: RNASEH2A plays a critical role and potentially predicts patient outcomes in HCC, which uncovers a new mechanism that RNASEH2A contributes to limit immunologic stress of cancer cells in the context of hypoxia.

Long-Term Protection of CHBP Against Combinational Renal Injury Induced by Both Ischemia-Reperfusion and Cyclosporine A in Mice.

Renal ischemia-reperfusion (IR) injury and cyclosporine A (CsA) nephrotoxicity affect allograft function and survival. The prolonged effects and underlying mechanisms of erythropoietin derived cyclic helix B peptide (CHBP) and/or caspase-3 small interfering RNA (CASP-3siRNA) were investigated in mouse kidneys, as well as kidney epithelial cells (TCMK-1), subjected to transplant-related injuries. Bilateral renal pedicles were clamped for 30 min followed by reperfusion for 2 and 8 weeks, with/without 35 mg/kg CsA gavage daily and/or 24 nmol/kg CHBP intraperitoneal injection every 3 days. The ratio of urinary albumin to creatinine was raised by IR injury, further increased by CsA and lowered by CHBP at 2, 4, 6 and 8 weeks, whereas the level of SCr was not significantly affected. Similar change trends were revealed in tubulointerstitial damage and fibrosis, HMGB1 and active CASP-3 protein. Increased apoptotic cells in IR kidneys were decreased by CsA and CHBP at 2 and/or 8 weeks. p70 S6 kinase and mTOR were reduced by CsA with/without CHBP at 2 weeks, so were S6 ribosomal protein and GSK-3ß at 8 weeks, with reduced CASP-3 at both time points. CASP-3 was further decreased by CHBP in IR or IR + CsA kidneys at 2 or 8 weeks. Furthermore, in TCMK-1 cells CsA induced apoptosis was decreased by CHBP and/or CASP-3siRNA treatment. Taken together, CHBP predominantly protects kidneys against IR injury at 2 weeks and/or CsA nephrotoxicity at 8 weeks, with different underlying mechanisms. Urinary albumin/creatinine is a good biomarker in monitoring the progression of transplant-related injuries. CsA divergently affects apoptosis in kidneys and cultured kidney epithelial cells, in which CHBP and/or CASP-3siRNA reduces inflammation and apoptosis.

Functional characterization of inward rectifier potassium ion channel in murine fetal ventricular cardiomyocytes.

AIMS: Previous studies have shown the dramatic changes in electrical properties of murine fetal cardiomyocytes, while details on inward rectifier potassium current (IK1) are still seldom discussed. Thus we aimed to characterize the functional expression and functional role of IK1 in murine fetal ventricular cardiomyocytes. METHODS: Whole cell patch clamp was applied to investigate the electrophysiological properties of IK1. Quantitative real-time PCR, western blotting and double-label immunofluorescence were further utilized to find out the molecular basis of IK1. RESULTS: Compared to early developmental stage (EDS), IK1 at late developmental stage (LDS) displayed higher current density, stronger rectifier property and faster activation kinetics. It was paralleled with the downregulation of Kir2.3 and the upregulation of Kir2.1/Kir2.2. IK1 contributed to maintain the maximum diastolic potential (MDP), late repolarization phase (LRP) as well as the action potential duration (APD). However, the contribution to MDP and velocity of LRP did not change significantly with maturation. CONCLUSIONS: During fetal development, the switch of IK1 subtypes from Kir2.1/Kir2.3 to Kir2.1 resulted in the dramatic changes in IK1 electrophysiological properties.

New insights into toxic effects of arsenate on four Microcystis species under different phosphorus regimes.

Very little information is available on the stressed growth of Microcystis imposed by arsenate (As(V)) under different phosphorus (P) regimes. In this study, we examined the growth characteristics and arsenic transformation of four Microcystis species exposed under As(V) with two P sources involving dissolved inorganic phosphorus (IP) and organophosphate (D-glucose-6-phosphate disodium salt, GP). Results showed that all the four chosen Microcystis species could grow and reproduce with GP as the only P source, and the difference was insignificant when compared with IP. From optical density (OD), chlorophyll a (Chla), and actual quantum yield (Yield), the tolerance to As(V) of the chosen species was following as FACHB 905 > FACHB 1028 > FACHB 1334 > FACHB 912. Specifically, the 96 h EC50 of As(V) for FACHB 905 in IP was approx. 4 orders of magnitude higher than that in GP, but for other three algal species, the 96 h EC50 values were similar under the two given different P conditions. Furthermore, all antioxidant enzyme activities of superoxide dismutase (SOD), peroxide dismutase (POD), glutathione S-transferases (GSTs), and metalloproteinase (MTs) in algal cells were significantly increased in GP conditions. Moreover, the enzyme activities of AKP, GSTs, and MTs were inhibited with increasing As(V) levels under both IP and GP conditions. In addition, arsenite (As(III)) and methylated As of monomethylarsonic acid (MMA) and dimethylthioarsinic acid (DMA) were found in FACHB 912 and FACHB 1334 media, indicating that these Microcystis could detoxify As(V) by As biotransformation under IP and GP conditions. Specifically, As(V) reduction was elevated in media of FACHB 1334 and FACHB 905, but was decreased in media of FACHB 912 under GP conditions. Our results highlight the different P sources that impact the toxic effects of arsenate exposure on Microcystis and subsequent As biotransformation.

Erythropoietin Derived Peptide Improved Endoplasmic Reticulum Stress and Ischemia-Reperfusion Related Cellular and Renal Injury.

Ischemia-reperfusion (IR) injury often affects transplant and native kidneys alike. IR injury is one of the main causes of acute kidney injury (AKI) and further associated with the progression of chronic kidney disease. Our previous study revealed the renoprotection of erythropoietin derived cyclic helix-B surface peptide (CHBP) against IR injury. However, the precise role and underlying mechanism of endoplasmic reticulum stress (ERS) in the injury and the renoprotection induced by IR or CHBP, respectively, have not been fully defined. This study using mouse kidney epithelial cells (TCMK-1) revealed that the level of CHOP (a key marker of ERS), PERK, and JNK (regulators of CHOP) was gradually increased by the prolonged time of hydrogen peroxide (H2O2) stimulation. In addition, CHOP mRNA and protein were significantly reduced by small interfering RNA (siRNA) target CHOP, as were apoptotic and inflammatory mediator caspase-3 and HMGB-1, and early apoptosis. Furthermore, CHOP mRNA was correlated positively with PERK protein, active caspase-3, HMGB-1 and apoptosis, but negatively with cell viability in vitro, while CHOP protein was also correlated positively with the level of tubulointerstitial damage and active caspase-3 protein in vivo. Finally, CHBP improved the viability of TCMK-1 cells subjected to H2O2 stimulation time-dependently, with reduced level of CHOP mRNA. CHBP also inhibited the increase of CHOP protein, not only in TCMK-1 cells, but also in the IR injury kidneys at 2 weeks. Moreover, CHBP reduced the expression of PERK mRNA and protein, JNK and HMGB-1 protein, as well as early and later apoptosis. In addition, raised CHOP at 12 h post IR injury might be an early time window for intervention. In conclusion, the differential role of ERS and CHBP in IR-related injury was proved in mouse TCMK-1 cells and kidneys, in which the mechanistic signaling pathway was associated with CHOP/PERK/JNK, HMGB-1/caspase-3, and apoptosis. CHOP might be a potential biomarker and CHBP might be therapeutic drug for IR-induced AKI.

Roles of TRPM7 in Renal Ischemia-Reperfusion Injury.

Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury (AKI) that is a global health concern associated with high morbidity and mortality. So far, no specific interventions limit injury or improve recovery and survival. Transient receptor potential melastatin 7 (TRPM7), a bifunctional membrane protein, plays key roles in inflammation and cell death. However, the precise role and underlying mechanism of TRPM7 in IR-induced AKI have not been well defined. Herein, we reviewed the structure and function of TRPM7 as a non-selective ion channel, but Ca2+ and Mg2+-conducting, that mediated the elevation of cytosolic Ca2+ and Mg2+. We then comprehensively reviewed the mechanism of TRPM7 involved in the pathophysiology of renal IRI, including inflammatory response, apoptosis and necroptosis, renal microvasculature, as well as maladaptive fibrogenesis leading to chronic kidney disease (CKD). Our previous study has shown that the dynamic change and underlying mechanism of TRPM7 involving in inflammation and apoptosis in in vitro hypoxia/reoxygenation and in vivo renal IRI models. The association between TRPM7, inflammatory response and apoptosis, as well as related caspase-3, HMGB1 and Bax/Bcl-2 ratio, was also discussed. Disclosing the involvement of TRPM7 in renal IRI might provide new mechanistic insights for a potential biomarker as diagnostic and therapeutic target of AKI.

Subacute Combined Degeneration, Pernicious Anemia and Gastric Neuroendocrine Tumor Occured Simultaneously Caused by Autoimmune Gastritis.

Subacute combined degeneration (SCD) is a relatively rare myelopathy mainly caused by vitamin B12 (VitB12) deficiency. There are many causes contributing to VitB12 deficiency. Autoimmune gastritis might lead to severe VitB12 malabsorption and in its advanced stage pernicious anemia (PA) may occur. Besides, long-term hypergastrinemia arising from achlorhydria in autoimmune gastritis is associated with neuroendocrine tumors (NETs). Patients diagnosed with SCD coexistent with PA and NET are seldomly reported. We describe a 34-year-old woman with an initial complaint of progressive fatigue, weakness and numbness in her limbs and disturbed gait. Physical examination revealed appearance of anemia, ataxia, decrease of superficial and deep sense, and positive Babinski's sign. Laboratory tests disclosed macrocytic anemia, elevated intrinsic factor antibody and spinal MRI showed extensive T2-weighted hyperintensity in the dorsal columns. A gastric polyp was revealed by gastroscopy and histology showed an NET in the background of severe atrophic gastritis. Symptoms of the patient were relieved by a multidisciplinary therapy. In patients with SCD, PA should be suspected and prompt further investigations to elucidate causes and direct treatment.