Reperfusion therapy, the standard treatment for acute myocardial infarction, can trigger necrotic death of cardiomyocytes and provoke ischemia/reperfusion (I/R) injury. However, signaling pathways ...that regulate cardiomyocyte necrosis remain largely unknown. Our recent genome-wide RNAi screen has identified a potential necrosis suppressor gene PRKAR1A, which encodes PKA regulatory subunit 1α (R1α). R1α is primarily known for regulating PKA activity by sequestering PKA catalytic subunits in the absence of cAMP. Here, we showed that depletion of R1α augmented cardiomyocyte necrosis in vitro and in vivo, resulting in exaggerated myocardial I/R injury and contractile dysfunction. Mechanistically, R1α loss downregulated the Nrf2 antioxidant transcription factor and aggravated oxidative stress following I/R. Degradation of the endogenous Nrf2 inhibitor Keap1 through p62-dependent selective autophagy was blocked by R1α depletion. Phosphorylation of p62 at Ser349 by mammalian target of rapamycin complex 1 (mTORC1), a critical step in p62-Keap1 interaction, was induced by I/R, but diminished by R1α loss. Activation of PKA by forskolin or isoproterenol almost completely abolished hydrogen-peroxide-induced p62 phosphorylation. In conclusion, R1α loss induces unrestrained PKA activation and impairs the mTORC1-p62-Keap1-Nrf2 antioxidant defense system, leading to aggravated oxidative stress, necrosis, and myocardial I/R injury. Our findings uncover a novel role of PKA in oxidative stress and necrosis, which may be exploited to develop new cardioprotective therapies.
The first line therapy for patients with diffuse large B cell (DLBCL) is R-CHOP. About half of DLBCL patients are either refractory to, or will relapse, after the treatment. Therefore, identifying ...novel drug targets and effective therapeutic agents is urgently needed for improving DLBCL patient survival. b-AP15, a selective small molecule inhibitor of proteasomal USP14 and UCHL5 deubiquitinases (DUBs), has shown selectivity and efficacy in several other types of cancer cells. This is the first study to report the effect of b-AP15 in DLBCL.
Cell lines of two DLBCL subtypes, Germinal Center B Cell/ GCB (SU-DHL-4, OCI-LY-1, OCI-LY-19) and Activated B Cell/ABC (SU-DHL-2), were used in the current study. Cell viability was measured by MTS assay, proliferation by trypan blue exclusion staining assay, cellular apoptosis by Annexin V-FITC/PI staining and mitochondrial outer membrane permeability assays, the activities of 20S proteasome peptidases by cleavage of specific fluorogenic substrates, and cell migration was detected by transwell assay in these GCB- and ABC-DLBCL cell lines. Mouse xenograft models of SU-DHL-4 and SU-DHL-2 cells were used to determine in vivo effects of b-AP15 in DLBCL tumors.
b-AP15 inhibited proteasome DUB activities and activated cell death pathway, as evident by caspase activation and mitochondria apoptosis in GCB- and ABC- DLBCL cell lines. b-AP15 treatment suppressed migration of GCB- and ABC-DLBCL cells via inhibiting Wnt/β-catenin and TGFβ/Smad pathways. Additionally, b-AP15 significantly inhibited the growth of GCB- and ABC DLBCL in xenograft models.
These results indicate that b-AP15 inhibits cell migration and induces apoptosis in GCB- and ABC-DLBCL cells, and suggest that inhibition of 19S proteasomal DUB should be a novel strategy for DLBCL treatment.
Triple-negative breast cancer (TNBC), as the most aggressive subtype of breast cancer, presents a scarcity of miraculous drugs in suppressing its proliferation and metastasis. Bruceine A (BA) is a ...functional group-rich quassin compound with extensive and distinctive pharmacological activities. Within the present study, we investigated the capabilities of BA in suppressing TNBC proliferation and metastasis as well as its potential mechanisms. The results displayed that BA dramatically repressed the proliferation of MDA-MB-231 and 4T1 cells with corresponding IC50 values of 78.4 nM and 524.6 nM, respectively. Concurrently, BA arrested cells in G1 phase by downregulating cycle-related proteins Cyclin D1 and CDK4. Furthermore, BA distinctly induced mitochondrial dysfunction as manifested by diminished mitochondrial membrane potential, elevated reactive oxygen species generation, minimized ATP production, and Caspase-dependent activation of the mitochondrial apoptosis pathway. Additionally, BA restrained the invasion and metastasis of TNBC cells by repressing MMP9 and MMP2 expression. Intriguingly, after pretreatment with MEK activator C16-PAF, the inhibitory effect of BA on MEK/ERK pathway was notably diminished, while the proliferation suppression and metastasis repression exerted by BA were all strikingly curtailed. Molecular docking illustrated that BA potently combined with residues on the MEK1 protein with the presence of diverse intermolecular interactions. Ultimately, BA effectively suppressed tumor growth in the 4T1 xenograft tumor model with no detectable visceral toxicity in the high-dose group and, astonishingly, repressed tumor metastasis in the 4T1-luc lung metastasis model. Collectively, our study demonstrates that BA is a promising chemotherapeutic agent for treating TNBC and suppressing lung metastasis.
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•The mechanism of action of BA in inhibiting TNBC was first explored.•BA can suppress the MEK/ERK pathway in vitro.•BA can activate the mitochondrial apoptosis pathway in vitro.•BA showed a strong affinity with MEK1.•BA inhibited tumor growth and metastasis in vivo and showed no tissue toxicity.
Abstract Background Acinetobacter lwoffii ( A. lwoffii ) is a Gram-negative bacteria common in the environment, and it is the normal flora in human respiratory and digestive tracts. The bacteria is a ...zoonotic and opportunistic pathogen that causes various infections, including nosocomial infections. The aim of this study was to identify A. lwoffii strains isolated from bovine milk with subclinical mastitis in China and get a better understanding of its antimicrobial susceptibility and resistance profile. This is the first study to analyze the drug resistance spectrum and corresponding mechanisms of A. lwoffii isolated in raw milk. Results Four A. lwoffii strains were isolated by PCR method. Genetic evolution analysis using the neighbor-joining method showed that the four strains had a high homology with Acinetobacter lwoffii . The strains were resistant to several antibiotics and carried 17 drug-resistance genes across them. Specifically, among 23 antibiotics, the strains were completely susceptible to 6 antibiotics, including doxycycline, erythromycin, polymyxin, clindamycin, imipenem, and meropenem. In addition, the strains showed variable resistance patterns. A total of 17 resistance genes, including plasmid-mediated resistance genes, were detected across the four strains. These genes mediated resistance to 5 classes of antimicrobials, including beta-lactam, aminoglycosides, fluoroquinolones, tetracycline, sulfonamides, and chloramphenicol. Conclusion These findings indicated that multi-drug resistant Acinetobacter lwoffii strains exist in raw milk of bovine with subclinical mastitis. Acinetobacter lwoffii are widespread in natural environmental samples, including water, soil, bathtub, soap box, skin, pharynx, conjunctiva, saliva, gastrointestinal tract, and vaginal secretions. The strains carry resistance genes in mobile genetic elements to enhance the spread of these genes. Therefore, more attention should be paid to epidemiological surveillance and drug resistant A. lwoffii .
Abstract Aims The anthracycline family of anticancer agents such as doxorubicin (DOX) can induce apoptotic death of cardiomyocytes and cause cardiotoxicity. We previously reported that DOX-induced ...apoptosis is accompanied by cardiomyocyte cell cycle re-entry. Cell cycle progression requires cyclin-dependent kinase 7 (CDK7)-mediated activation of downstream cell cycle CDKs. This study aims to determine whether CDK7 can be targeted for cardioprotection during anthracycline chemotherapy. Methods and results DOX exposure induced CDK7 activation in mouse heart and isolated cardiomyocytes. Cardiac-specific ablation of Cdk7 attenuated DOX-induced cardiac dysfunction and fibrosis. Treatment with the covalent CDK7 inhibitor THZ1 also protected against DOX-induced cardiomyopathy and apoptosis. DOX treatment induced activation of the proapoptotic CDK2–FOXO1–Bim axis in a CDK7-dependent manner. In response to DOX, endogenous CDK7 directly bound and phosphorylated CDK2 at Thr160 in cardiomyocytes, leading to full CDK2 kinase activation. Importantly, inhibition of CDK7 further suppressed tumour growth when used in combination with DOX in an immunocompetent mouse model of breast cancer. Conclusion Activation of CDK7 is necessary for DOX-induced cardiomyocyte apoptosis and cardiomyopathy. Our findings uncover a novel proapoptotic role for CDK7 in cardiomyocytes. Moreover, this study suggests that inhibition of CDK7 attenuates DOX-induced cardiotoxicity but augments the anticancer efficacy of DOX. Therefore, combined administration of CDK7 inhibitor and DOX may exhibit diminished cardiotoxicity but superior anticancer activity.
Cell cycle progression in dividing cells, characterized by faithful replication of the genomic materials and duplication of the original cell, is fundamental for growth and reproduction of all ...mammalian organisms. Functional maturation of postmitotic cells, however, requires cell cycle exit and terminal differentiation. In mature postmitotic cells, many cell cycle proteins remain to be expressed, or can be induced and reactivated in pathological conditions such as traumatic injury and degenerative diseases. Interestingly, elevated levels of cell cycle proteins in postmitotic cells often do not induce proliferation, but result in aberrant cell cycle reentry and cell death. At present, the cell cycle machinery is known predominantly for regulating cell cycle progression and cell proliferation, albeit accumulating evidence indicates that cell cycle proteins may also control cell death, especially in postmitotic tissues. Herein, we provide a brief summary of these findings and hope to highlight the connection between cell cycle reentry and postmitotic cell death. In addition, we also outline the signaling pathways that have been identified in cell cycle-related cell death. Advanced understanding of the molecular mechanisms underlying cell cycle-related death is of paramount importance because this knowledge can be applied to develop protective strategies against pathologies in postmitotic tissues. Moreover, a full-scope understanding of the cell cycle machinery will allow fine tuning to favor cell proliferation over cell death, thereby potentially promoting tissue regeneration.
The aims of the present study are to describe the status of self-management behaviors and illness perception, and explore the relationship between illness perception and self-management behaviors ...among Chinese diabetic foot patients.
A cross-sectional study was conducted at the endocrinology department of a comprehensive tertiary hospital in Guangzhou, China. Data were collected on illness perception, self-management behaviors, and demographic and clinical characteristics over 9 months among 156 subjects. Data were analyzed using Pearson correlation analysis, univariate analysis and multiple linear regression analysis.
Only 3.2% of participants maintained excellent self-management behaviors. Additionally, the participants perceived diabetic foot as chronic and could be well controlled through treatment. Multiple linear regression analysis revealed that illness perception was associated with self-management behaviors.
Patient illness perception is an important factor influencing self-management behaviors. It may be helpful to improve self-management behaviors by tailoring the content of the intervention to fit the patients' illness perceptions.
Tolls/Toll-like receptors (TLRs) are a group of pattern recognition receptors (PRRs) that play central roles in the regulation of immune responses by sensing invading pathogens and initiating the ...downstream signaling pathways. In this study, a novel Toll (Toll10) from pacific white shrimp Penaeus vannamei has been identified and functionally studied in the context of immunity to bacterial infection. Toll10 has a series of tandem leucine-rich repeats (LRR) in the extracellular region but not a Toll/interleukin-1(IL-1) receptor homologous region (TIR) in the intracellular region. The Toll10 protein mainly locates on the cell membrane and its expression is up-regulated upon bacterial infection. The recombinant Toll10 protein can directly bind bacteria, and silencing of Toll10 increases the susceptibility of shrimp to Vibrio parahaemolyticus infection and inhibits the phagocytosis of V. parahaemolyticus by hemocytes. Moreover, Toll10 promotes the phosphorylation and nuclear translocation of the NF-κB family member Dorsal and positively regulates the expression of Dorsal-targeted antimicrobial peptide genes. This indicates that Toll10 mediates a signaling pathway to activate Dorsal and is important for antibacterial immune response in P. vannamei. The current study is helpful for the revelation of the regulatory mechanism of immune defense in shrimp against V. parahaemolyticus infection.
•Toll10 is a novel member of the Toll family in Penaeus vannamei.•Toll10 promotes the activation of the NF-κB family member Dorsal.•Toll10 plays important role in immune response against Vibrio parahemolyticus infection.
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