Preparation of antioxidant peptides from yak skin gelatin and their protective effect on myocardial ischemia reperfusion injury.

We herein report a study on the antioxidant peptides that show potential in alleviating myocardial ischemia reperfusion injury (MI/RI). Yak skin gelatin fraction Ac (YSG-Ac), obtained through ultrafiltration and gel filtration with Sephadex G-15, exhibits a favorable nutrient composition, high foaming capacity and stability, and resistance against gastrointestinal digestion. LC-MS/MS analysis reveals that YSG-Ac contains 26 peptide segments with sequence lengths of 8 to 12 amino acids. Online screening suggests that the antioxidant capacity of YSG-Ac is mainly attributed to the presence of hydrophobic and antioxidant amino acids. In vitro, our results demonstrate the MI/RI protective effects of YSG-Ac by effectively repairing H2O2-induced oxidative damage in H9c2 cells, which is achieved by inhibiting malondialdehyde (MDA) levels, and increasing glutathione peroxidase (GSH-pX) and superoxide dismutase (SOD) activity. In vivo, our results further confirm the effectiveness of YSG-Ac in narrowing the area of myocardial infarction, decreasing MDA levels, increasing SOD activity, and reducing the content of lactate dehydrogenase (LDH) in a mouse MI/RI model. Molecular docking analysis indicates that PGADGQPGAK with xanthine dehydrogenase (XDH) and GAAGPTGPIGS with tumor necrosis factor-alpha (TNF-α) exhibit strong bonding capability, and other related targets also show certain binding ability toward YSG-Ac. This suggests that YSG-Ac can regulate MI/RI through multiple targets and pathways. Overall, our findings highlight the potential of YSG-Ac as a functional food ingredient with antioxidant and MI/RI protective characteristics.

Synthesis and antitumor activities of α-hydroxyamino phosphine oxides by catalyst-free hydrophosphinylation of nitrones.

Inspired by the diverse bioactivities of α-amino phosphine oxides, an efficient strategy for the synthesis of less researched α-(hydroxyamino)diarylphosphine oxides has been developed and their antitumor activities are explored. Under water as a solvent and catalyst-free conditions, the addition of nitrones and diphenylphosphine oxide occurs smoothly to afford α-(hydroxyamino) diarylphosphine oxides in high yields. This reaction features a wide substrate scope, facile starting materials, atom economy, and easy purification. Moreover, the biological evaluation revealed that two synthesized derivatives 5e and 5f could serve as interesting anti-cancer agents for further development.

MicroRNA-27a Regulates Ferroptosis Through SLC7A11 to Aggravate Cerebral ischemia-reperfusion Injury.

Cerebral ischemia-reperfusion (I/R) injury is an inevitable issue in the treatment of ischemic stroke, which has a high disability rate and seriously threatens the living quality of patients. Previous studies have demonstrated that ferroptosis, which plays a crucial role in ischemia-reperfusion injury, can be accelerated by microRNA-27a (miR-27a). However, the mechanism by which miR-27a regulates ferroptosis in cerebral ischemia-reperfusion injury remains unknown. In this study, Male Sprague-Dawley rats were subjected to a middle cerebral artery occlusion (MCAO), then restored blood flow. Neurological function score and TTC staining were used to evaluate brain tissue injury and the infarct volume. The relative expression level of miR-27a was detected by qPCR. The relative expression levels of glutathione peroxidase 4(GPx4), solute carrier family 7 member 11 (SLC7A11) proteins were analyzed by Western Blot. The contents of GSH, Fe and malonaldehyde (MDA) were detected by corresponding detection kits, and the target gene of miR-27a was confirmed by dual luciferase reporter gene technique. It was found the relative expression level of miR-27a was increased and ferroptosis was aggravated as reperfusion time went by. Also, brain tissue injury and ferroptosis were exacerbated with agomiR-27a intervention, while these effects were reversed with antagomiR-27a intervention. In addition, the combined intervention of agomiR-27a and Fer-1 alleviated the brain tissue injury and ferroptosis. The results of dual luciferase reporter gene technique indicated SLC7A11 as the target gene of miR-27a. In the current study, miR-27a upregulates ferroptosis to aggravate cerebral ischemia-reperfusion injury by SLC7A11.

Multivalent Pyrrolidine Iminosugars: Synthesis and Biological Relevance.

Recently, the strategy of multivalency has been widely employed to design glycosidase inhibitors, as glycomimetic clusters often induce marked enzyme inhibition relative to monovalent analogs. Polyhydroxylated pyrrolidines, one of the most studied classes of iminosugars, are an attractive moiety due to their potent and specific inhibition of glycosidases and glycosyltransferases, which are associated with many crucial biological processes. The development of multivalent pyrrolidine derivatives as glycosidase inhibitors has resulted in several promising compounds that stand out. Herein, we comprehensively summarized the different synthetic approaches to the preparation of multivalent pyrrolidine clusters, from total synthesis of divalent iminosugars to complex architectures bearing twelve pyrrolidine motifs. Enzyme inhibitory properties and multivalent effects of these synthesized iminosugars were further discussed, especially for some less studied therapeutically relevant enzymes. We envision that this comprehensive review will help extend the applications of multivalent pyrrolidine iminosugars in future studies.

Micro Ribonucleic Acid 27a Aggravates Ferroptosis During Early Ischemic Stroke of Rats Through Nuclear Factor Erythroid-2-Related Factor 2.

Ischaemic stroke (IS) is characterized by high morbidity, disability and mortality and lacks effective solutions. MiRNA-27a has been implicated in ferroptosis, but evidence that miRNA-27a regulates ferroptosis in ischaemic stroke is lacking. Nrf2 could reduce brain tissue injury in ischaemic stroke and resist ferroptosis. The current study aimed to investigate the relationship between miRNA-27a/Nrf2 and ferroptosis in ischaemic stroke. In this study, IS was simulated using a permanent middle cerebral artery occlusion (pMCAO) model. The degree of brain tissue injury was assessed by conducting TTC staining and neurological function scoring. MiRNA-27a expression levels were altered via the intracerebroventricular injection of miRNA­27a agonist or antagonist. Glutathione peroxidase 4 (GPX4), glutathione (GSH), Fe and malondialdehyde (MDA) are considered biomarkers for ferroptosis. The expression of GPX4 and Nrf2 was analysed by Western blot assay. The GSH, Fe and MDA contents were detected by detection kits. We found that the expression levels of Fe and MDA were increased, while GPX4 and GSH were decreased in the pMCAO groups compared with the control group. These results indicated that ferroptosis intensified over time during IS. In addition, the miRNA­27a agonist significantly aggravated ferroptosis and reduced neurological function scores compared with those of the control group. Subsequently, a luciferase reporter gene system verified the targeted binding of miRNA­27a to Nrf2. The results showed that miRNA­27a inhibited Nrf2 in a targeted manner, which also exacerbated the extent of ferroptosis. However, the miRNA­27a antagonist reversed the miR­27a agonist­mediated effects. Therefore, the present study indicated that miRNA­27a may aggravate brain tissue ferroptosis during ischaemic stroke, potentially by inhibiting Nrf2.

[miR-27a induces ferroptosis by inhibiting solute carrier family 7 member-11 (SLC7A11) and causes cerebral ischemia-reperfusion injury in rats].

Objective To investigate the role and molecular mechanism of miR-27a in cerebral ischemia reperfusion injury model in rats. Methods The male Sprague Dawley rats were randomly divided into control group, sham group, middle cerebral artery occlusion/reperfusion model group(MCAO/R group)( according to different ischemia reperfusion time, the model group was divided into the 3, 6, 12 and 24 hours reperfusion groups after 2 hour-ischemia), and vehicle group, agomir-27a group, antagomir-27a group. The Zea-Longa method was used to establish rat MCAO model. The levels of miR-27a and solute carrier family 7 member-11 (SLC7A11) in brain tissues were detected by real-time fluorescence quantitative PCR. Zea-Longa score was used to evaluate neuro score. 2, 3, 5 triphenyl tetrazolium chloride(TTC) staining was used to test the infarct volume. The relative expression levels of glutathione peroxidase 4(GPx4) and SLC7A11 proteins were detected by Western blot analysis. The contents of GSH, Fe and MDA were detected by GSH, Fe and MDA detection kits. The target gene of miR-27a was confirmed by dual luciferase reporter gene technique. Results After cerebral ischemia reperfusion, the level of miR-27a was up-regulated and the level of SLC7A11 was down-regulated. Inhibition of miR-27a expression reduced neurological score and cerebral infarct volume, and inhibited ferroptosis after cerebral ischemia reperfusion. Conclusion In the process of cerebral ischemia and reperfusion, the up-regulated miR-27a may induce ferroptosis through inhibiting SLC7A11, thus causing brain tissue damage.

MicroRNA-124 regulates cell pyroptosis during cerebral ischemia-reperfusion injury by regulating STAT3.

Cerebral ischemia-reperfusion injury (CIRI) is the observed continuation and deterioration of ischemic injury, and currently, there are no effective treatment strategies for the condition. It has been reported that microRNAs (miRNAs) serve an important role in CIRI by regulating pyroptosis. The present study demonstrated that miRNA-124 regulated CIRI by regulating STAT3. To explore the relationship between miRNA-124/STAT3 and pyroptosis in CIRI, CIRI was simulated using a middle cerebral artery occlusion model. Subsequently, miRNA-124 expression levels were altered via the intracerebroventricular injection of miRNA-124 agonist or antagonist. The degree of brain tissue injury was assessed by conducting TTC staining and neurological function scoring. Relative miRNA-124 expression levels were determined via reverse transcription-quantitative PCR. A luciferase reporter gene system verified the targeted binding of miRNA-124 to STAT3. The expression levels of key proteins and proinflammatory cytokines associated with pyroptosis [caspase-1, gasdermin D, interleukin (IL)-18 and IL-1ß] were detected via western blotting and immunohistochemistry. The increased expression levels of pyroptosis-associated proteins and proinflammatory cytokines in the I/R groups compared with the control group, indicated that pyroptosis intensified over time during CIRI, and miRNA-124 agonist significantly abrogated pyroptosis and improved neurological function compared with the control group. Furthermore, miRNA-124 inhibited STAT3 activation in a targeted manner, which also decreased the extent of pyroptosis. However, miRNA-124 antagonist reversed miR-124 agonist-mediated effects. Therefore, the present study indicated that miRNA-124 may provide neuroprotection against pyroptosis during CIRI, potentially via inhibition of the STAT3 signaling pathway.

MicroRNA-124 expression in the brains of rats during early cerebral ischemia and reperfusion injury is associated with cell apoptosis involving STAT3.

Cerebral ischemia and reperfusion injury is a cause of death and disability in adults. MicroRNA-124 possesses protective effects against apoptosis in cerebral ischemia and reperfusion. To provide insights into the diagnosis and treatment of cerebral ischemia and reperfusion injury, the dynamic changes of microRNA-124 expression during the early stage of cerebral ischemia and reperfusion injury in rats was investigated by quantitative polymerase chain reaction. To elucidate the association between the dynamic expression of microRNA-124 and apoptosis, the expression of proteins associated with apoptosis, including caspase-3, apoptosis regulator Bcl-2 (Bcl-2) and apoptosis regulator Bax (Bax) was analyzed by immunohistochemistry and western blot analyses. As signal transducer and activator of transcription 3 (STAT3) is involved in cell apoptosis and associated with Bcl-2, the protein expression of STAT3 and its active form, phosphorylated (p-)STAT3, were analyzed by western blot analysis. The expression of microRNA-124 increased and the maximum value appeared 12 h after reperfusion. Similarly, the expression of Bcl-2 also peaked 12 h after reperfusion, however the expression of caspase-3 and Bax continued to increase after the 12 h time point. These results indicate that the expression of microRNA-124 is closely associated with Bcl-2 and serves a protective role, inhibiting apoptosis. As the upstream regulator of Bcl-2, the expression of p-STAT3 was in accordance with Bcl-2 expression and peaked 12 h after reperfusion. By contrast, STAT3 was downregulated and the minimum level of STAT3 protein was reached 12 h after reperfusion. In summary, during the early stage of cerebral ischemia and reperfusion, the dynamic expression of microRNA-124 exhibited protective effects through the inhibition of apoptosis via anti-apoptotic proteins Bcl-2 and STAT3. Conversely, caspase-3 and Bax maintain apoptosis. The present study provides evidence to aid in the understanding of cerebral ischemia and reperfusion injury and develops methods of diagnosis and therapy of this condition.

Insight into the binding interaction of kaempferol-7-O-α-L-rhamnopyranoside with human serum albumin by multiple fluorescence spectroscopy and molecular modeling.

Human serum albumin (HSA) is a transporting protein that has multiple functions. The binding interaction between HSA and small molecules affects its function and efficacy of small molecules. The present study reports that kaempferol-7-O-α-L-rhamnopyranoside (KR) interacts with HSA as indicated by multiple fluorescence spectroscopy and molecular modeling. KR can quench the intrinsic fluorescence of HSA through the formation of a KR-HSA complex in a static manner. In addition, the binding site is located in subdomain IIA as confirmed by competitive experiments using site-specific warfarin and ibuprofen, and the driving forces include hydrogen bonds, van der Waals forces and electrostatic interaction derived from a thermodynamic analysis. The formation of KR-HSA is exothermic and spontaneous. Although there is no hydrophobic interaction around Tyr and Trp residues, the secondary structure of HSA changes through the formation of the KR-HSA complex. In addition, docking results visualized and further supported these results. Finally, these results can provide more information to further investigate the use of KR on the prevention of diabetic complications.

Design, synthesis and bioactivity evaluation of Galf mimics as antitubercular agents.

A series of novel Galf mimics has been synthesized and characterized by IR, (1)H NMR, (13)C NMR, mass spectral and element analysis. All the newly prepared compounds were screened for their antitubercular activities. Bioactivity assays manifested that most of Galf mimics exhibited good antitubercular activities. Especially compound 4d and 4e displayed remarkable antitubercular efficacies, which were comparable to ethambutol.

[Regulation of transplantation of human umbilical cord blood derived mesenchymal stem cells on secretion of neural biochemistry marker after traumatic brain injury in rats].

This research was to study the regulation of intravenous administration of human umbilical cord blood mesenchymal stem cells (HUCBMSCs) on secretion of neural specific protein in rats after traumatic brain injury (TBI), and to explore its mechanisms promoting the recovery of neurological function. The TBI models of rats were established. We then injected HUCBMSCs, labelled by Brdu (5-bromo-2-deoxyuridine), into the TBI rats via the tail vein using modified Feeney free-falling method. The levels of neural biochemical indicators (serum S100ß protein, NSE, LDH, CK) of rats were detected in shamed group, injury group and HUCBMSCs-transplanted group. And the morphological changes of brain tissue of rats in the three groups were observed by using HE staining under light microscope. During the whole experiment no immunosuppressant was used for the four groups. From the research, transplant-related death of the rats was not found in transplantation group. In the injury group, rises were found in contents of serum S100ß protein, NSE, LDH, CK in the early stage after the rats were injured, which were much higher than those in shamed group at correspondent time point (P < 0.01). In HUCBMSCs-transplanted group, although these biochemistry indexes were found rising for a short period in the early stage, along with the time, these indexes were obviously lower than in those injury group (P < 0.05). Under light microscopy pathological changes of rats in HUCBMSCs-transplanted group were much slighter than those in injury group. It was well concluded that in the situation of no immuno-suppressants, the intravenous-injected HUCBMSCs could reduce the secretion of serum S100ß protein, NSE, LDH, CK, promote the repair of tissue injury effectively, and promote the functional recovery of neurons.

[Analysis of Volatile Components of Polypodium hastatum by GC-MS].

OBJECTIVE: To further reveal the chemical constituents of Polypodium hastatum, volatile components from this plant were investigated. METHODS: The volatile components were extracted under reflux from the whole plant of Polypodium hastatum, and then analyzed qualitatively and quantitatively by GC-MS. RESULTS: 60 volatile components were detected and of all components detected, the structures and relative contents of 34 volatile compounds were elucidated. CONCLUSION: In the volatile components identified, most are fatty acid esters, especially methyl and ethyl esters, which compose the major volatile chemical constituents of Polypodium hastatum.

Induction of G2/M arrest by pseudolaric acid B is mediated by activation of the ATM signaling pathway.

AIM: The aim of this study was to investigate the mechanism of pseudolaric acid B (PLAB)-induced cell cycle arrest in human melanoma SK-28 cells. METHODS: Cell growth inhibition was detected by MTT assay, the cell cycle was analyzed by flow cytometry, and protein expression was examined by Western blot analysis. RESULTS: PLAB inhibited the growth of human melanoma cells and induced G(2)/M arrest in SK-28 cells, accompanied by an up-regulation of Cdc2 phosphorylation and a subsequent down-regulation of Cdc2 expression. Furthermore, PLAB decreased the expression of Cdc25C phosphatase and increased the expression of Wee1 kinase. Meanwhile, a reduction in Cdc2 activity was partly due to induction of the expression of p21(waf1/cip1) in a p53-dependent manner. In addition, PLAB activated the checkpoint kinase, Chk2, and increased the expression of p53, two major targets of ATM kinase. These effects were inhibited by caffeine, an ATM kinase inhibitor. We also found that PLAB significantly enhanced ATM kinase activity. CONCLUSION: Taken together, these results suggest that PLAB induced G(2)/M arrest in human melanoma cells via a mechanism involving the activation of ATM, and the effect of PLAB on Cdc2 activity was mediated via interactions with the Chk2-Cdc25C and p53 signalling pathways, two distinct downstream pathways of ATM. PLAB may be a promising chemopreventive agent for treating human melanoma.

Pseudolaric acid B-induced apoptosis through p53-dependent pathway in human gastric carcinoma cells.

Pseudolaric acid B (PLAB, 1), a natural diterpenoid compound, was isolated from Pseudolarix kaempferi Gordon. It has shown antifungal, antifertility, and antiangiogenic properties in previous studies. Recently, increasing evidence has confirmed that 1 exhibits antitumor effects in several tumor cell lines, but the underlying mechanism has not been fully elucidated. The aim of this study was to investigate the mechanism of PLAB-induced cell apoptosis in MGC803 cells. The results showed that 1 significantly inhibited the proliferation of MGC803 cells at 0.01-10 microM and the IC(50) value was 0.91 microM for 48 h. PLAB-induced apoptosis in MGC803 cells was confirmed by DNA fragmentation assay and Hoechst33342/PI staining. PLAB-treated MGC803 cells were arrested at G(2) phase, which was associated with a marked increment of the expression of cyclin-dependent kinase inhibitor p21. The induction of p21 appeared to be transcriptionally up-regulated and was p53-dependent. In addition, PLAB induced Fas/APO-1 and caspase-3 expressions that were also correlated with apoptosis. Meanwhile, 1 decreased the mRNA expression of bcl-2, which is an antiapoptosis factor. In conclusion, 1 induced apoptosis through p53-dependent pathway in human gastric carcinoma cells. These findings suggest that 1 may be a novel promising agent for treating human gastric carcinoma.