Broad Spectrum Mixed Lineage Kinase Type 3 Inhibition and HIV-1 Persistence in Macrophages

Functions of MAP3Ks in antiviral immunity

Immune signal transduction is crucial to the body's defense against viral infection. Recognition of pathogen-associated molecular patterns by pattern recognition receptors (PRRs) activates the transcription of interferon regulators and nuclear factor-κB (NF-κB); this promotes the release of interferons and inflammatory factors. Efficient regulation of type I interferon and NF-κB signaling by members of the mitogen-activated protein (MAP) kinase kinase kinase (MAP3K) family plays an important role in antiviral immunity. Elucidating the specific roles of MAP3K activation during viral infection is essential to develop effective antiviral therapies. In this review, we outline the specific regulatory mechanisms of MAP3Ks in antiviral immunity and discuss the feasibility of targeting MAP3Ks for the treatment of virus-induced diseases.

Xinyang Tablet inhibits MLK3-mediated pyroptosis to attenuate inflammation and cardiac dysfunction in pressure overload

ETHNOPHARMACOLOGICAL RELEVANCE

Xinyang tablet (XYT) has been traditionally used in the treatment of cardiovascular diseases (CVDs). Our previous study indicated that XYT exhibited protective effects in heart failure (HF).

AIM OF THE STUDY

The aim of the present study was to determine the protective effects of XYT in pressure overload induced HF and to elucidate its underlying mechanisms of action.

MATERIALS AND METHODS

We analyzed XYT content using high-performance liquid chromatography (HPLC.). Mice were subjected to transverse aortic constriction (TAC) to generate pressure overload-induced cardiac remodeling and were then orally administered XYT or URMC-099 for 1 week after the operation. HL1 mouse cardiomyoblasts were induced by lipopolysaccharides (LPS) to trigger pyroptosis and were then treated with XYT or URMC-099. We used echocardiography (ECG), hematoxylin and eosin (H&E) staining, Masson's trichrome staining and a terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay to evaluate the effects of XYT. Messenger ribonucleic acid (mRNA) levels of collagen metabolism biomarkers and inflammation-related factors were detected. We determined protein levels of inflammation- and pyroptosis-related signaling pathway members via Western blot (WB). Caspase-1 activity was measured in cell lysate using a Caspase-1 Activity Assay Kit. Subsequently, to define the candidate ingredients in XYT that regulate mixed-lineage kinase-3 (MLK3), we used molecular docking (MD) to predict and evaluate binding affinity with MLK3. Finally, we screened 24 active potential compounds that regulate MLK3 via MD.

RESULTS

ECG, H&E staining, Masson's trichrome staining and TUNEL assay results showed that XYT remarkably improved heart function, amelorated myocardial fibrosis and inhibited apoptosis in vivo. Moreover, it reduced expression of proteins or mRNAs related to collagen metabolism, including collagen type 1 (COL1), fibronectin (FN), alpha smooth-muscle actin (α-SMA), and matrix metalloproteinases-2 and -9 (MMP-2, MMP-9). XYT also inhibited inflammation and the induction of pyroptosis at an early stage, as well as attenuated inflammation and pyroptosis levels in vitro.

CONCLUSION

Our data indicated that XYT exerted protective effects against pressure overload induced myocardial fibrosis (MF), which might be associated with the induction of pyroptosis-mediated MLK3 signaling.

Pyroptosis and ferroptosis induced by mixed lineage kinase 3 (MLK3) signaling in cardiomyocytes are essential for myocardial fibrosis in response to pressure overload

Chronic heart failure (CHF) is the final outcome of many cardiovascular diseases, and is a severe health issue faced by the elderly population. Mixed lineage kinase 3 (MLK3), a member of MAP3K family, is associated with aging, inflammation, oxidative stress, and related diseases, such as CHF. MLK3 has also been reported to play an important role in protecting against cardiomyocyte injury; however, its function in myocardial fibrosis is unknown. To investigate the role of MLK3 in myocardial fibrosis, we inhibited the expression of MLK3, and examined cardiac function and remodeling in TAC mice. In addition, we assessed the expression of MLK3 protein in ventricular cells and its downstream associated protein. We found that MLK3 mainly regulates NF-κB/NLRP3 signaling pathway-mediated inflammation and that pyroptosis causes myocardial fibrosis in the early stages of CHF. Similarly, MLK3 mainly regulates the JNK/p53 signaling pathway-mediated oxidative stress and that ferroptosis causes myocardial fibrosis in the advanced stages of CHF. We also found that promoting the expression of miR-351 can inhibit the expression of MLK3, and significantly improve cardiac function in mice subjected to TAC. These results suggest the pyroptosis and ferroptosis induced by MLK3 signaling in cardiomyocytes are essential for adverse myocardial fibrosis, in response to pressure overload. Furthermore, miR-351, which has a protective effect on ventricular remodeling in heart failure caused by pressure overload, may be a key target for the regulation of MLK3.

Editor's Commentary for Special Issue: "The Role of Macrophages in HIV Persistence"

Macrophages as reservoirs for persistent HIV infection has gained renewed importance, with an intense research focus dedicated to eradication strategies. Clearance of both latent and productive HIV from these important reservoirs is essential for successful eradication. This spe cial theme issue contains 11 papers, including 6 Invited Reviews, 1 Brief Report and 4 Original Articles, that focus on the various aspects of the macrophage as pertains to HIV persistence, latency and cure. These topics include: functional latency of macrophages and microglia, the link between peripheral monocytes and pathogenesis, macrophages as sources of HIV RNA and DNA in virally suppressed patients, brain imaging of neuroinflammation, macrophages as drug delivery vehicles, therapeutic strategies of infected macrophages for cure, and the role of drugs of abuse in enhancing macrophage viral persistence.