Early secreted antigenic target of 6-kDa of Mycobacterium tuberculosis promotes caspase-9/caspase-3-mediated apoptosis in macrophages.

Mycobacterium tuberculosis (Mtb) is an intracellular pathogen that triggers several survival mechanisms against the host immune system. Many studies show that the diverse components of Mtb can modulate apoptosis in various types of cells differently. So far, apoptosis induced by ESAT-6, an early secreted antigenic target of 6-kDa of Mtb, has been studied but the details of molecular mechanism and signaling pathway remain incompletely defined. This study investigated the role of recombinant ESAT-6 in inducing apoptosis in primary bone marrow-derived macrophages (BMDMs) of mice using Annexin V/PI assay with FACS analysis and Western blotting technique. It has been found that ESAT-6-induced apoptosis in BMDMs in a dose- and time-dependent pattern. Apoptosis induced by ESAT-6 was mainly via the intrinsic pathway with elevated protein levels of cleaved caspase-9 and -3. Furthermore, ESAT-6 also induced Bim activation during this process. Interestingly, this event was TLR2-dependent since the effect of ESAT-6 on apoptosis vanished in BMDM from mice with TLR2 deficiency. Furthermore, ROS generation and MAPKs phosphorylation induced by ESAT-6 were also involved in caspase-9 and caspase-3 activation. Taken together, these data suggest that ESAT-6-mediated apoptosis is involved in ROS-MAPKs signaling and further activating the intrinsic pathway, which provides new insights into the basic physiology of macrophage death in tuberculosis.

ZNF397 Deficiency Triggers TET2-Driven Lineage Plasticity and AR-Targeted Therapy Resistance in Prostate Cancer.

Cancer cells exhibit phenotypical plasticity and epigenetic reprogramming that allows them to evade lineage-dependent targeted treatments by adopting lineage plasticity. The underlying mechanisms by which cancer cells exploit the epigenetic regulatory machinery to acquire lineage plasticity and therapy resistance remain poorly understood. We identified zinc finger protein 397 (ZNF397) as a bona fide coactivator of the androgen receptor (AR), essential for the transcriptional program governing AR-driven luminal lineage. ZNF397 deficiency facilitates the transition of cancer cell from an AR-driven luminal lineage to a ten-eleven translocation 2 (TET2)-driven lineage plastic state, ultimately promoting resistance to therapies inhibiting AR signaling. Intriguingly, our findings indicate that a TET2 inhibitor can eliminate the resistance to AR-targeted therapies in ZNF397-deficient tumors. These insights uncover a novel mechanism through which prostate cancer acquires lineage plasticity via epigenetic rewiring and offer promising implications for clinical interventions designed to overcome therapy resistance dictated by lineage plasticity. Significance: This study reveals a bifurcated role of ZNF397, and a TET2-driven epigenetic mechanism regulating tumor lineage plasticity and therapy response in prostate cancer, enhances the understanding of drug resistance, and unveils a new therapeutic strategy for overcoming androgen receptor-targeted therapy resistance.

Preparation and characteristics of a novel oxygen-releasing coating for improved cell responses in hypoxic environment.

Affected by environmental factors such as oxygen deficiency, the secretion of growth factor was abnormal in bone injury sites, resulting in the poor responses of osteoblasts and prolonging the healing process. Herein, in this study, we reported an in situ oxygen-releasing porous titanium coating that combines the dual degradability of poly(lactic-co-glycolic acid) with the self-releasing oxygen capacity of the CaO2 core. The resulting formulation exhibited stable oxygen-releasing capacity as well as the ability to promote proliferation and differentiation of the MC3T3 cell line under hypoxia conditions. According to these results, oxygen-releasing coatings based on improved cellular microenvironment may be a promising bone repair material that would reduce the incidence of difficult bone healing in the future.

Early secreted antigenic target of 6-kDa of Mycobacterium tuberculosis induces transition of macrophages into epithelioid macrophages by downregulating iNOS / NO-mediated H3K27 trimethylation in macrophages.

BACKGROUND: Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb). Granuloma is a pathological feature of tuberculosis and is a tight immune cell aggregation caused by Mtb. The main constituent cells are macrophages and their derivative cells including epithelioid macrophages. However, the molecular mechanism of the transition has not been reported. The purpose of this study was to investigate whether early secreted antigenic target of 6-kDa (ESAT6) can induce the transition of bone marrow-derived macrophages (BMDMs) into epithelioid macrophages and its possible molecular mechanism. METHODS: The recombinant ESAT6 protein was obtained from E.coli carrying esat6 gene after isopropyl ß-d-thiogalactopyranoside (IPTG) induction. BMDMs were isolated from bone marrow of mice hind legs. Cells viability was detected by Cell Counting Kit 8 (CCK8) assays. The expression levels of mRNA and proteins were detected by qPCR and Western blot, or evaluated by flow cytometry. The expression level of nitric oxide (NO) was measured with a nitric oxide indicator. RESULTS: ESAT6 could significantly induce mRNA and protein expression levels of a group of epithelioid macrophages marker molecules (EMMMs), including E-cadherin, junction plakoglobin, ZO1, desmoplakin, desmoglein3 and catenin porteins, in BMDMs. These events could be abrogated in macrophage from TLR2 deficiency mice. ESAT6 could also markedly induce iNOS/NO production that could significantly inhibit trimethylation of H3K27 in the cells. ESAT6-induced expressions of epithelioid macrophages marker molecules were significantly inhibited in the presence of H3K27 histone demethylase inhibitor GSK J1. Furthermore, ROS scavenging agent N,N'-Dimethylthiourea (DMTU) could markedly inhibit the transition induced by ESAT6 in macrophages. CONCLUSION: This study demonstrates that ESAT6 bound with TLR2 can activate iNOS/NO and ROS signalings to reduce the trimethylation of H3K27 resulting in the increment of EMMMs expression that is beneficial to the transition of macrophages into epithelioid macrophages. However, hypoxia can inhibit this transition event. This study has provided new evidence of pathogenesis of granuloma caused by Mtb and also proposed new ideas for the treatment of TB.