SAK-HV Decreases the Self-Ubiquitination of MEKK1 to Promote Macrophage Proliferation via MAPK/ERK and JNK Pathways

EGCG alleviated Mn exposure-caused carp kidney damage via trpm2-NLRP3-TNF-α-JNK pathway: Oxidative stress, inflammation, and tight junction dysfunction

Manganese (Mn), an essential trace metal element in organisms. However, with extensive use of Mn in industry and agriculture, Mn becomes a heavy metal pollutant in water. (-)-epigallocatechin gallate (EGCG), an tea polyphenols, can alleviate metal toxicity. Kidney is an important detoxifying organ, but toxic mechanism of Mn to kidneys is unclear, which needs further research. Carp is an Asian important economical species for fisheries and a biological model for studying environmental toxicology. Thus, we established excess Mn and EGCG-supplemented carp model to explore molecular mechanism of EGCG alleviating Mn-caused carp kidney damage. In this experiment, we set a control group (the Con group), a Mn treatment group (the Mn group, 90 mg/L Mn), a EGCG supplement group (the EG group, 75 mg/kg EGCG), and a combined group (the Mn + EG group, 90 mg/L Mn and 75 mg/kg EGCG). Transcriptome, qRT-PCR, kit, and morphology method results indicated that excess Mn caused oxidative stress, inflammatory damage, and tight junction dysfunction in carp kidneys. Excess Mn-triggered oxidative stress caused tight junction dysfunction via trpm2-NLRP3-TNF-α-JNK pathway and inflammation. EGCG reversed the harm of Mn to fish through the above mechanism. The findings of this study provided the evidence of EGCG-alleviated Mn poisoning and offered new ideas for reducing heavy metal environmental pollution risk.

Impact of Ubiquitination Signaling Pathway Modifications on Oral Carcinoma

Among intra-cellular homeostasis mechanisms, ubiquitination plays a critical role in protein metabolism regulation by degrading proteins via activating a broad spectrum of ubiquitin chains. In fact, ubiquitination and sumoylation signaling pathways are characterized by increased complexity regarding the molecules and their interactions. The Ubiquitin-Proteasome System (Ub-PS) recognizes and targets a broad spectrum of protein substrates. Ubiquitin conjugation modifies each substrate protein determining its biochemical fate (degradation). A major functional activity of Ub-PS is autophagy mechanism regulation. Interestingly, Ub-PS promotes all stages of bulk autophagy (initiation, execution, and termination). Autophagy is a crucial catabolic process that provides protein degradation and for this reason the interaction with Ub-PS is crucial. Furthermore, ubiquitination controls and regulates specific types of protein targets. Ub-PS is also involved in oxidative cellular stress and DNA damage response. Additionally, the functional role of Ub-PS in ribosome machinery regulation seems to be crucial. Concerning carcinogenesis, Ub-PS is involved in malignant disease development and progression by negatively affecting the corresponding TGF-B-, MEEK/MAPK/ERK-JNK- dependent signaling pathways. In the current review article, we describe the role of Ub-PS biochemical modifications and alterations in oral squamous cell carcinoma (OSCC).

Norcantharidin Enhances High Concentrations of Fetal Bovine Serum-Induced Apoptosis in Human Mesangial Cells by Regulating the Mitogen-Activated Protein Kinase Signaling Pathway

AIM

This study aimed to investigate the effect of norcantharidin (NCTD) on human mesangial cells (HMCs) apoptosis in vitro and further examine its molecular mechanism.

METHODS

HMCs were divided into 5 groups: control group, 25% fetal bovine serum (FBS)-treated group, and NCTD groups (NCTD [2.5, 5 and 10 µg/mL] + 25% FBS, respectively). Cell proliferation was determined by MTT assay, while apoptosis was evaluated by Hoechest 33258 staining, the level of cytochrome c, immunohistochemistry, and apoptotic-related proteins/gene expression.

RESULTS

Cell viability was inhibited in NCTD-treated HMCs in a dose-dependent manner. The number of apoptotic cells and the content of cytochrome c were significantly increased by NCTD treatment but that of mitochondrial membrane was decreased. Moreover, the expression of bcl-2 and caspase-3 was prompted by NCTD, but the expression of bax, MMP-2, and MMP-9 in 25% FBS-treated HMCs was inhibited. In addition, NCTD markedly unregulated the expression of apoptosis-related gene/protein, including p-Erk1/2, phosphorylated-Jun N-terminal kinase (JNK), p-p38, and p53.

CONCLUSION

NCTD enhances 25% FBS-treated HMC apoptosis in vitro, and this effect may be attributed to the modulation of the ERK, JNK, and p38 mitogen-activated protein kinase signaling pathways.

SAK-HV Promotes RAW264.7 cells Migration Mediated by MCP-1 via JNK and NF-κB Pathways

Macrophage migration plays an essential role in immune system and is also involved in many pathological situations. However, the regulatory mechanism of macrophage migration remains to be elucidated due to its diverse responses to various stimuli. SAK-HV, a multifunctional protein possessing thrombolytic and lipid-lowering activity, can selectively induce the macrophage proliferation. Here, we reported SAK-HV significantly triggered RAW264.7 cells migration through its functional domain of SAK-mutant by activating both c-jun N-terminal kinases (JNK) and nuclear factor-κB (NF-κB) pathways. Meanwhile, SAK-HV upregulated the expression of some effector proteins, among which only the expression of Monocyte chemoattractant protein-1 (MCP-1) was inhibited by the blockade of JNK and NF-κB pathways. Further research showed that MCP-1 promoted migration ultimately by interacting with Chemokine (C-C motif) Receptor 2 (CCR2) in an autocrine manner. In summary, SAK-HV induced RAW264.7 cells migration through its SAK-mutant domain, during which MCP-1 chemokine mediated by JNK and NF-κB pathways played a key role. These results revealed a novel effect of SAK-HV on modulating macrophage migration and also deepened the understanding of its pharmacodynamics.