The intracellular signaling mechanisms underlying postnatal angiogenesis are incompletely understood. Herein we show that Grb-2–associated binder 1 (Gab1) plays a critical role in ischemic and VEGF-induced angiogenesis. Endothelium-specific Gab1 KO (EGKO) mice displayed impaired angiogenesis in the ischemic hindlimb despite normal induction of VEGF expression. Matrigel plugs with VEGF implanted in EGKO mice induced fewer capillaries than those in control mice. The vessels and endothelial cells (ECs) derived from EGKO mice were defective in vascular sprouting and tube formation induced by VEGF. Biochemical analyses revealed a substantial reduction of endothelial NOS (eNOS) activation in Gab1-deficient vessels and ECs following VEGF stimulation. Interestingly, the phosphorylation of Akt, an enzyme known to promote VEGF-induced eNOS activation, was increased in Gab1-deficient vessels and ECs whereas protein kinase A (PKA) activity was significantly decreased. Introduction of an active form of PKA rescued VEGF-induced eNOS activation and tube formation in EGKO ECs. Reexpression of WT or mutant Gab1 molecules in EGKO ECs revealed requirement of Gab1/Shp2 association for the activation of PKA and eNOS. Taken together, these results identify Gab1 as a critical upstream signaling component in VEGF-induced eNOS activation and tube formation, which is dependent on PKA. Of note, this pathway is conserved in primary human ECs for VEGF-induced eNOS activation and tube formation, suggesting considerable potential in treatment of human ischemic diseases.

Carbon quantum dots (CQDs) offer huge potential due to their enzymatic properties as compared to natural enzymes. Thus, discovery of CQDs-based nanozymes with low toxicity from natural resources, especially daily food, implies a promising direction for exploring treatment strategies for human diseases. Here, we report a CQDs-based biocompatible nanozyme prepared from chlorogenic acid (ChA), a major bioactive natural product from coffee. We found that ChA CQDs exhibited obvious GSH oxidase-like activities and subsequently promoted cancer cell ferroptosis by perturbation of GPX4catalyzed lipid repair systems. In vivo, ChA CQDs dramatically suppressed the tumor growth in HepG2-tumor-bearing mice with negligible side toxicity. Particularly, in hepatoma H22-bearing mice, ChA CQDs recruited massive tumor-infiltrating immune cells including T cells, NK cells, and macrophages, thereby converting "cold" to "hot" tumors for activating systemic antitumor immune responses. Taken together, our study suggests that natural product-derived CQDs from coffee can serve as biologically safe nanozymes for anticancer therapeutics and may aid the development of nanotechnology-based immunotherapeutic.

Key pointsr Loss of slow skeletal muscle troponin T (ssTnT) due to a nonsense mutation in codon Glu 180 causes a lethal form of recessively inherited nemaline myopathy.r We studied the phenotypes of partial and total loss of ssTnT in the diaphragm and soleus muscles of Tnnt1 gene targeted mice.r ssTnT deficiency resulted in significant decreases in other slow fibre-specific myofilament proteins whereas fast fibre-specific myofilament proteins were increased correspondingly.r ssTnT deficiency produced significantly smaller type I slow fibres and compensatory growth of type II fast fibres with significantly reduced contractile force and tolerance to fatigue.r ssTnT-deficient soleus muscle exhibited a significant numbers of small-sized central nuclei type I fibres, indicating regeneration.r The data support the critical role of ssTnT in skeletal muscle function and the causal effect of its loss on the pathogenesis of nemaline myopathy. AbstractThe total loss of slow skeletal muscle troponin T (ssTnT encoded by TNNT1 gene) due to a nonsense mutation in codon Glu 180 causes a lethal form of recessively inherited nemaline myopathy (Amish nemaline myopathy, ANM). To investigate the pathogenesis and muscle pathophysiology of ANM, we studied the phenotypes of partial and total loss of ssTnT in Tnnt1 gene targeted mice. An insertion of neomycin resistance cassette in intron 10 of Tnnt1 gene caused an approximately 60% decrease in ssTnT protein expression whereas cre-loxP-mediated deletion of exons 11-13 resulted in total loss of ssTnT, as seen in ANM muscles. In diaphragm and soleus muscles of the knockdown and knockout mouse models, we demonstrated that ssTnT deficiency resulted in significantly decreased levels of other slow fibre-specific myofilament proteins whereas fast fibre-specific myofilament proteins were increased correspondingly. Immunohistochemical studies revealed that ssTnT deficiency produced significantly smaller type I slow fibres and compensatory growth of type II fast fibres. Along with the slow fibre atrophy and the changes in myofilament protein isoform contents, ssTnT deficiency significantly reduced the tolerance to fatigue in soleus muscle. ssTnT-deficient soleus muscle also contains significant numbers of small-sized central nuclei type I fibres, indicating active regeneration. The data provide strong support for the essential role of ssTnT in skeletal muscle function and the causal effect of its loss in the pathology of ANM. This observation further supports the hypothesis that the function of slow fibres can be restored in ANM patients if a therapeutic supplement of ssTnT is achieved.

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Abnormal angiogenesis is critical for portal hypertension in cirrhosis. Except for etiological treatment, no efficient medication or regime has been explored to treat the early stage of cirrhosis when angiogenesis is initiated or overwhelming. In this study, we explored an anti-angiogenesis effort through non-cytotoxic drugs octreotide and celecoxib to treat early stage of cirrhotic portal hypertension in an animal model. Peritoneal injection of thioacetamide (TAA) was employed to induce liver cirrhosis in rats. A combination treatment of celecoxib and octreotide was found to relieve liver fibrosis, portal venous pressure, micro-hepatic arterioportal fistulas, intrahepatic and splanchnic angiogenesis. Celecoxib and octreotide exerted their anti-angiogenesis effect via an axis of cyclooxygenase-2/prostaglandin E2/EP-2/somatostatin receptor-2, which consequently down-regulated phosphorylation of extracellular signal-regulated kinase (p-ERK)–hypoxia-inducible factor-1α (HIF-1α)–vascular endothelial growth factor (VEGF) integrated signaling pathways. In conclusions, combination of celecoxib and octreotide synergistically ameliorated liver fibrosis and portal hypertension of the cirrhotic rats induced by TAA via the inhibition of intrahepatic and extrahepatic angiogenesis. The potential mechanisms behind the regimen may due to the inactivation of p-ERK–HIF-1α–VEGF signaling pathway.Electronic supplementary materialThe online version of this article (doi:10.1007/s10456-016-9522-9) contains supplementary material, which is available to authorized users.

Background: Corona Virus Disease 2019 (COVID-19) has become a global pandemic. This study established prognostic scoring models based on comorbidities and other clinical information for severe and critical patients with COVID-19. Material and Methods: We retrospectively collected data from 51 patients diagnosed as severe or critical COVID-19 who were admitted between January 29, 2020, and February 18, 2020. The Charlson (CCI), Elixhauser (ECI), and age-and smoking-adjusted Charlson (ASCCI) and Elixhauser (ASECI) comorbidity indices were used to evaluate the patient outcomes. Results: The mean hospital length of stay (LOS) of the COVID-19 patients was 22.82 ± 12.32 days; 19 patients (37.3%) were hospitalized for more than 24 days. Multivariate analysis identified older age (OR 1.064, P = 0.018, 95%CI 1.011-1.121) and smoking (OR 3.696, P = 0.080, 95%CI 0.856-15.955) as positive predictors of a long LOS. There were significant trends for increasing hospital LOS with increasing CCI, ASCCI, and ASECI scores (OR 57.500,

A vital step in the development of heart failure is the transition from compensatory cardiac hypertrophy to decompensated dilated cardiomyopathy (DCM) during cardiac remodeling under mechanical or pathological stress. However, the molecular mechanisms underlying the development of DCM and heart failure remain incompletely understood. In the present study, we investigate whether Gab1, a scaffolding adaptor protein, protects against hemodynamic stress-induced DCM and heat failure. We first observed that the protein levels of Gab1 were markedly reduced in hearts from human patients with DCM and from mice with experimental viral myocarditis in which DCM developed. Next, we generated cardiac-specific Gab1 knockout mice (Gab1-cKO) and found that GabcKO mice developed DCM in hemodynamic stress-dependent and age-dependent manners. Under transverse aorta constriction (TAC), Gab1-cKO mice rapidly developed decompensated DCM and heart failure, whereas Gab1 wild-type littermates exhibited adaptive left ventricular hypertrophy without changes in cardiac function. Mechanistically, we showed that Gab1-cKO mouse hearts displayed severe mitochondrial damages and increased cardiomyocyte apoptosis. Loss of cardiac Gab1 in mice impaired Gab1 downstream MAPK signaling pathways in the heart under TAC. Gene profiles further revealed that ablation of Gab1 in heart disrupts the balance of anti-and pro-apoptotic genes in cardiomyocytes. These results demonstrate that cardiomyocyte Gab1 is a critical regulator of the compensatory cardiac response to aging and hemodynamic stress. These findings may provide new mechanistic insights and potential therapeutic target for DCM and heart failure. The progression of heart failure is associated with cardiac remodeling, the changes of cardiac structure and function in response to various stress conditions such as pressure overload-generated hemodynamic stress and agingassociated oxidative stress. 1 Under hemodynamic stress, the heart undergoes a stage of compensated hypertrophy and then progresses into decompensated dilated cardiomyopathy (DCM) and heart failure. 2 Cardiac hypertrophy is an adaptive, regulatory process, in which activation of cardiomyocyte survival pathways maintains cardiac homeostasis against external stress. During the transition from compensatory hypertrophy to DCM, cardiomyocyte death plays a critical role in development of heart failure. [3][4][5][6] However, the molecular mechanisms for controlling the balance of cell survival and cell death during cardiac remodeling remain poorly understood.The Grb2-associated binder 1 (Gab1) is a member of the insulin receptor substrate-like multi-substrate docking protein family and expressed in various types of cells, including cardiomyocytes. [7][8][9] It is a central mediator of growth factor receptor signaling. 10,11 Gab1 is phosphorylated by tyrosine kinases, and then phosphorylated Gab1 recruits and activates phosphatidylinositol 3-kinase (PI3K)/Akt and protein tyrosine phosphatase SHP2 (PTPN11)/mitogen-activated protein kinase (MAPK...

We have shown recently that endothelial Grb-2-associated binder 1 (Gab1), an intracellular scaffolding adaptor, has a protective effect against limb ischemia via mediating angiogenic signaling pathways. However, the role of Gab1 in cardiac ischemia/reperfusion (I/R) injury remains unknown. In this study, we show that Gab1 is required for cardioprotection against I/R injury. I/R injury led to remarkable phosphorylation of Gab1 in cardiomyocytes. Compared with controls, the mice with cardiomyocyte-specific deletion of Gab1 gene (CGKO mice) exhibited an increase in infarct size and a decrease in cardiac function after I/R injury. Consistently, in hearts of CGKO mice subjected to I/R, the activation of caspase 3 and myocardial apoptosis was markedly enhanced whereas the activation of protein kinase B (Akt) and mitogen-activated protein kinase (MAPK), which are critical for cardiomyocyte survival, was attenuated. Oxidative stress is regarded as a major contributor to myocardial I/R injury. To examine the role of Gab1 in oxidative stress directly, isolated adult cardiomyocytes were subject to oxidant hydrogen peroxide and the cardioprotective effects of Gab1 were confirmed. Furthermore, we found that the phosphorylation of Gab1 and Gab1-mediated activation of Akt and MAPK by oxidative stress was suppressed by ErbB receptor and Src kinase inhibitors, accompanied by an increase in apoptotic cell death. In conclusion, our results suggest that Gab1 is essential for cardioprotection against I/R oxidative injury via mediating survival signaling.