GSK-3α/β Activity Negatively Regulates MMP-1/9 Expression to Suppress Mycobacterium tuberculosis Infection

Arcyriaflavin A, a cyclin D1/CDK4 inhibitor, suppresses tumor growth, migration, and invasion of metastatic melanoma cells

BACKGROUND

Despite advancements in targeted therapy and immunotherapy, cutaneous melanoma continues to have a high mortality rate and poor prognosis, with therapies having limited efficacy in advanced melanoma. Therefore, it is crucial to develop novel therapeutics with proven clinical potential. In this study, we evaluated the efficacy of arcyriaflavin A (ArcA), a potent inhibitor of the cyclin D1/CDK4 complex, in suppressing aggressive phenotypes of metastatic melanoma.

METHODS

The effects of ArcA on viability and cell cycle were evaluated across four melanoma cell lines: WM239A and its metastatic derivatives: 113-6/4L, 131/4-5B1, and 131/4-5B2. Additionally, we performed wound healing and transwell invasion assays, followed by western blot. We further established xenograft mouse models by subcutaneously injecting them with the four melanoma cell lines and measured tumor size and weight biweekly. Immunohistochemistry analysis was performed to compare protein expression.

RESULTS

ArcA demonstrated dose-dependent cytotoxicity, selectively targeting melanoma cells without affecting normal cells, and induced G1 cell cycle arrest. Moreover, ArcA significantly inhibited cell migration and invasion in metastatic melanoma cell lines, accompanied by reduced expression levels of p-GSK-3β (Ser9), MMP-9, and MMP-13, suggesting that its anti-metastatic effects may be partially mediated through GSK-3β, MMP-9, and MMP-13. These findings were further validated using mouse xenograft models; ArcA-treated mice exhibited significantly smaller tumor volumes and lighter tumor weights compared to vehicle-treated mice. Immunohistochemistry further confirmed decreased expression of p-GSK-3β, MMP-9, and MMP-13 in tumor tissues from ArcA-treated mice.

CONCLUSIONS

Collectively, our findings indicate that ArcA possesses substantial anti-tumor potential, including cytotoxic effects and inhibition of migration and invasion in metastatic melanoma. These results suggest that ArcA could enhance therapeutic efficacy in the treatment of metastatic melanoma.

Glycogen synthase kinase-3β: A multifaceted player in ischemia-reperfusion injury and its therapeutic prospects

Ischemia-reperfusion injury (IRI) results in irreversible metabolic dysfunction and structural damage to tissues or organs, posing a formidable challenge in the field of organ implantation, cardiothoracic surgery, and general surgery. Glycogen synthase kinase-3β (GSK-3β) a multifunctional serine/threonine kinase, is involved in a variety of biological processes, including cell proliferation, apoptosis, and immune response. Phosphorylation of its tyrosine 216 and serine 9 sites positively and negatively regulates the activation and inactivation of the enzyme. Significantly, inhibition or inactivation of GSK-3β provides protection against IRI, making it a viable target for drug development. Though numerous GSK-3β inhibitors have been identified to date, the development of therapeutic treatments remains a considerable distance away. In light of this, this review summarizes the complicated network of GSK-3β roles in IRI. First, we provide an overview of GSK-3β's basic background. Subsequently, we briefly review the pathological mechanisms of GSK-3β in accelerating IRI, and highlight the latest progress of GSK-3β in multiorgan IRI, encompassing heart, brain, kidney, liver, and intestine. Finally, we discuss the current development of GSK-3β inhibitors in various organ IRI, offering a thorough and insightful reference for GSK-3β as a potential target for future IRI therapy.

Glycogen synthase kinase 3 inhibition controls Mycobacterium tuberculosis infection

Compounds targeting host control of infectious diseases provide an attractive alternative to antimicrobials. A phenotypic screen of a kinase library identified compounds targeting glycogen synthase kinase 3 as potent inhibitors of Mycobacterium tuberculosis (Mtb) intracellular growth in the human THP-1 cell line and primary human monocytes-derived macrophages (hMDM). CRISPR knockouts and siRNA silencing showed that GSK3 isoforms are needed for the growth of Mtb and that a selected compound, P-4423632 targets GSK3β. GSK3 inhibition was associated with macrophage apoptosis governed by the Mtb secreted protein tyrosine phosphatase A (PtpA). Phospho-proteome analysis of macrophages response to infection revealed a wide array of host signaling and apoptosis pathways controlled by GSK3 and targeted by P-4423632. P-4423632 was additionally found to be active against other intracellular pathogens. Our findings strengthen the notion that targeting host signaling to promote the infected cell's innate antimicrobial capacity is a feasible and attractive host-directed therapy approach.

RNA Expression of MMP12 Is Strongly Associated with Inflammatory Bowel Disease and Is Regulated by Metabolic Pathways in RAW 264.7 Macrophages

Macrophage metalloelastase or matrix metalloproteinase-12 (MMP12) is a macrophage-specific proteolytic enzyme involved in the physiopathology of many inflammatory diseases, including inflammatory bowel disease. Although previously published data suggested that the modulation of MMP12 in macrophages could be a determinant for the development of intestinal inflammation, scarce information is available on the mechanisms underlying the regulation of MMP12 expression in those phagocytes. Therefore, in this study, we aimed to delineate the association of MMP12 with inflammatory bowel disease and the molecular events leading to the transcriptional control of this metalloproteinase. For that, we used publicly available transcriptional data. Also, we worked with the RAW 264.7 macrophage cell line for functional experiments. Our results showed a strong association of MMP12 expression with the severity of inflammatory bowel disease and the response to relevant biological therapies. In vitro assays revealed that the inhibition of mechanistic target of rapamycin complex 1 (mTORC1) and the stimulation of the AMP-activated protein kinase (AMPK) signaling pathway potentiated the expression of Mmp12. Additionally, AMPK and mTOR required a functional downstream glycolytic pathway to fully engage with Mmp12 expression. Finally, the pharmacological inhibition of MMP12 abolished the expression of the proinflammatory cytokine Interleukin-6 (Il6) in macrophages. Overall, our findings provide a better understanding of the mechanistic regulation of MMP12 in macrophages and its relationship with inflammation.

Leptin Induces MMP-1 Expression Through the RhoA/ERK1/2/NF-κB Axis in Human Intervertebral Disc Cartilage Endplate-Derived Stem Cells

Purpose

Intervertebral disc (IVD) degeneration, associated with aging, may cause low back pain and disability, with obesity as a significant risk factor. In a prior study, we found a positive correlation between IVD degeneration and levels of matrix metalloproteinase-1 (MMP-1) and leptin. Yet, the interaction between MMP-1 and leptin in IVD degeneration is unclear. Our research seeks to explore leptin's influence on MMP-1 expression and the underlying mechanisms in human intervertebral disc cartilage endplate-derived stem cells, specifically SV40 cells.

Methods

The mRNA and protein expression in leptin-stimulated SV40 cells were assessed using RT-real-time PCR and Western blotting or ELISA, respectively. We examined leptin-mediated RhoA activation through a GTP-bound RhoA pull-down assay. Furthermore, the phosphorylation levels of mitogen-activated protein kinases and AKT in leptin-stimulated SV40 cells were analyzed using Western blotting. The activation of NF-κB by leptin was investigated by assessing phosphorylation of IKKα/β, IκBα, and NF-κB p65, along with the nuclear translocation of NF-κB p65. To understand the underlying mechanism behind leptin-mediated MMP-1 expression, we employed specific inhibitors.

Results

Leptin triggered the mRNA and protein expression of MMP-1 in SV40 cells. In-depth mechanistic investigations uncovered that leptin heightened RhoA activity, promoted ERK1/2 phosphorylation, and increased NF-κB activity. However, leptin did not induce phosphorylation of JNK1/2, p38, or AKT. When we inhibited RhoA, ERK1/2, and NF-κB, it resulted in a decrease in MMP-1 expression. Conversely, inhibition of reactive oxygen species and NADPH oxidase did not yield the same outcome. Additionally, inhibiting RhoA or ERK1/2 led to a reduction in leptin-induced NF-κB activation. Moreover, inhibiting RhoA also decreased leptin-mediated ERK1/2 phosphorylation.

Conclusion

These results indicated that leptin induced MMP-1 expression in SV40 cells through the RhoA/ERK1/2/NF-κB axis. This study provided the pathogenic role of leptin and suggested the potential therapeutic target for IVD degeneration.

Sp1 transcription factor represses transcription of phosphatase and tensin homolog to aggravate lung injury in mice with type 2 diabetes mellitus-pulmonary tuberculosis

Type 2 diabetes mellitus (T2DM) can enhance the risk of mycobacterium tuberculosis (Mtb) infection and aggravate pulmonary tuberculosis (PTB). This study intended to explore the function of phosphatase and tensin homolog (PTEN) in T2DM-PTB and the molecules involved. Mice were treated with streptozotocin to induce T2DM and then infected with Mtb. The mice with T2DM had increased weight, blood glucose level, glucose intolerance and insulin resistance, and increased susceptibility to PTB after Mtb infection. PTEN was significantly downregulated in mice with T2DM-PTB and it had specific predictive value in patients. Overexpression of PTEN improved mouse survival and reduced bacterial load, inflammatory infiltration, cell apoptosis, and fibrosis in lung tissues. Sp1 transcription factor (SP1) was predicted and identified as an upstream regulator of PTEN. SP1 suppressed PTEN transcription. Silencing of SP1 enhanced mouse survival and alleviated the lung injury, and it promoted the M1 polarization of macrophages in murine lung tissues. However, further downregulation of PTEN increased protein kinase B (Akt) phosphorylation and blocked the alleviating roles of SP1 silencing in T2DM-PTB. This study demonstrates that SP1 represses PTEN transcription to promote lung injury in mice with T2DM-PTB through Akt activation.