Aims: We investigated the role of transient receptor potential vanilloid receptor type 1 (TRPV1) in simvastatin-mediated activation of endothelial nitric oxide synthase (eNOS) and angiogenesis. Methods: Fluo-8 NW assay was for Ca 2+ detection; Griess's assay was for NO bioavailability; Western blotting and immunoprecipitation were for protein phosphorylation and interaction; tube formation and Matrigel plug assay were for angiogenesis. Results: In endothelial cells (ECs), treatment with simvastatin time-dependently increased intracellular level of Ca 2+ . Pharmacological inhibition or genetic disruption of TRPV1 abrogated simvastatin-mediated elevation of intracellular Ca 2+ in ECs or TRPV1-transfected HEK293 cells. Loss of TRPV1 function abolished simvastatin-induced NO production and phosphorylation of eNOS and calmodulin protein kinase II (CaMKII) in ECs and in aortas of mice. Inhibition of TRPV1 activation prevented the simvastatin-elicited increase in the formation of TRPV1-Akt-CaMKII-AMPK-eNOS complex. In mice, Matrigel plug assay showed that simvastatin-evoked angiogenesis was abolished by TRPV1 antagonist and genetic ablation of TRPV1. Additionally, our results demonstrated that TRP ankyrin 1 (TRPA1) is the downstream effector in the simvastatin-activated TRPV1-Ca 2+ signalling and in the consequent NO production and angiogenesis as evidence by that re-expression of TRPA1 further augmented simvastatin-elicited Ca 2+ influx in TRPV1-expressed HEK293 cells and ablation of TRPA1 function profoundly inhibited the simvastatin-induced increase in the phosphorylation of eNOS and CaMKII, formation of TRPV1-Akt-CaMKII-AMPK-eNOS complex, NO bioavailability, tube formation and angiogenesis in ECs or mice. Conclusion: Simvastatin-induced Ca 2+ influx may through the activation of TRPV1-TRPA1 signalling, which leads to phosphorylation of CaMKII, increases in the formation of TRPV1-CaMKII-AMPK-eNOS complex, eNOS activation, NO production and, ultimately, angiogenesis in ECs.

Mitophagy is thought to play a key role in eliminating damaged mitochondria, with diseases such as cancer and neurodegeneration exhibiting defects in this process. Mitophagy is also involved in cell differentiation and maturation, potentially through modulating mitochondrial metabolic reprogramming. Here we examined mitophagy that is induced upon iron chelation and found that the transcriptional activity of HIF1α, in part through upregulation of BNIP3 and NIX, is an essential mediator of this pathway in SH-SY5Y cells. In contrast, HIF1α is dispensable for mitophagy occurring upon mitochondrial depolarisation. To examine the role of this pathway in a metabolic reprogramming and differentiation context, we utilised the H9c2 cell line model of cardiomyocyte maturation. During differentiation of these cardiomyoblasts, mitophagy increased and required HIF1α-dependent upregulation of NIX. Though HIF1α was essential for expression of key cardiomyocyte markers, mitophagy was not directly required. However, enhancing mitophagy through NIX overexpression, accelerated marker gene expression. Taken together, our findings provide a molecular link between mitophagy signalling and cardiomyocyte differentiation and suggest that although mitophagy may not be essential per se, it plays a critical role in maintaining mitochondrial integrity during this energy demanding process.

Sulfonated aluminum phthalocyanines (AlPcSs), commonly used photosensitizers for photodynamic therapy of cancers (PDT), were conjugated with amine-dihydrolipoic acid-coated quantum dots (QDs) by electrostatic binding, achieving 70 AlPcSs per QD. The AlPcS-QD conjugates can utilize the intense light absorptions of conjugated QDs to indirectly excite AlPcSs producing singlet oxygen via fluorescence resonance energy transfer (FRET), demonstrating a new excitation model for PDT. The AlPcS-QD conjugates easily penetrated into human nasopharyngeal carcinoma cells and carried out the FRET in cells, with efficiency around 80%. Under the irradiation of a 532-nm laser, which is at the absorption region of QDs but not fit for the absorption of AlPcSs, the cellular AlPcS-QD conjugates can destroy most cancer cells via FRET-mediated PDT, showing the potential of this new strategy for PDT.

Bcl2 has been reported to suppress DNA mismatch repair (MMR) with promotion of mutagenesis, but the mechanism(s) is not fully understood. MutS␣ is the hMSH2-hMSH6 heterodimer that primarily functions to correct mutations that escape the proofreading activity of DNA polymerase. Here we have discovered that Bcl2 potently suppresses MMR in association with decreased MutS␣ activity and increased mutagenesis. Exposure of cells to nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone results in accumulation of Bcl2 in the nucleus, which interacts with hMSH6 but not hMSH2 via its BH4 domain. Deletion of the BH4 domain from Bcl2 abrogates the ability of Bcl2 to interact with hMSH6 and is associated with enhanced MMR efficiency and decreased mutation frequency. Overexpression of Bcl2 reduces formation of the hMSH2-hMSH6 complex in cells, and purified Bcl2 protein directly disrupts the hMSH2-hMSH6 complex and suppresses MMR in vitro. Importantly, depletion of endogenous Bcl2 by RNA interference enhances formation of the hMSH2-hMSH6 complex in association with increased MMR and decreased mutagenesis. Thus, Bcl2 suppression of MMR may occur in a novel mechanism by directly regulating the heterodimeric hMSH2-hMSH6 complex, which potentially contributes to genetic instability and carcinogenesis.Bcl2 is a proto-oncogene that was first identified at the chromosomal breakpoint of t(14;18) found in non-Hodgkin lymphoma, which is involved in dysregulated apoptotic cell death during the carcinogenic process (1). Bcl2 is widely expressed in various malignancies, including hematopoietic lung, breast, prostate, and nasopharyngeal cancers (2). However, the mechanism(s) by which Bcl2 facilitates oncogenesis is not fully understood. Because overexpression of Bcl2 results in lymphomagenesis in transgenic mice, this suggests that Bcl2, in addition to its survival activity, may also potentially have an oncogenic property (3). It has been reported that Bcl2 can enhance the benzene metabolite-induced DNA damage and mutagenesis in human promyelocytic HL60 cells (4). Overexpression of Bcl2 not only attenuates the nucleotide excision repair capacity and DNA replication in UV-irradiated HL60 cells (5) but also inhibits gamma ray-induced homologous recombination repair pathways, which result in elevated frequencies of mutagenesis (6). A recent report has proposed that Bcl2 can suppress DNA mismatch repair (MMR) 3 by inhibiting E2F transcriptional activity (7). Thus, the oncogenic activity of Bcl2 may occur through multiple regulatory pathways.MMR is a critical mechanism for maintaining genetic integrity by correcting base substitution and insertion/deletion loop mismatches that occur because of errors in DNA replication and recombination as well as DNA lesions resulting from a variety of internal and external stresses (8). The MMR system in human cells is composed of at least eight genes, including hMSH2, hMSH3, hMSH4, hMSH5, hMSH6 (GTBP), hMLH1, hPMS1, and hPMS2 (9, 10). The mismatch is detected by two major mismatch recognition complexes ...

EGCG may trigger activation of TRPV1-Ca(2+) signaling, which leads to phosphorylation of Akt, AMPK, and CaMKII; eNOS activation; NO production; and, ultimately, angiogenesis in ECs.