Selective Extracellular Signal-Regulated Kinase 1/2 (ERK1/2) Inhibition by the SCH772984 Compound Attenuates In Vitro and In Vivo Inflammatory Responses and Prolongs Survival in Murine Sepsis Models

A critical role for HNF4α in polymicrobial sepsis-associated metabolic reprogramming and death

In sepsis, limited food intake and increased energy expenditure induce a starvation response, which is compromised by a quick decline in the expression of hepatic PPARα, a transcription factor essential in intracellular catabolism of free fatty acids. The mechanism upstream of this PPARα downregulation is unknown. We found that sepsis causes a progressive hepatic loss-of-function of HNF4α, which has a strong impact on the expression of several important nuclear receptors, including PPARα. HNF4α depletion in hepatocytes dramatically increases sepsis lethality, steatosis, and organ damage and prevents an adequate response to IL6, which is critical for liver regeneration and survival. An HNF4α agonist protects against sepsis at all levels, irrespectively of bacterial loads, suggesting HNF4α is crucial in tolerance to sepsis. In conclusion, hepatic HNF4α activity is decreased during sepsis, causing PPARα downregulation, metabolic problems, and a disturbed IL6-mediated acute phase response. The findings provide new insights and therapeutic options in sepsis.

Echinatin alleviates sepsis severity through modulation of the NF-κB and MEK/ERK signaling pathways

Sepsis, a frequently fatal condition, emerges from an exaggerated inflammatory response to infection, resulting in multi-organ dysfunction and alarmingly high mortality rates. Despite the urgent need for effective treatments, current therapeutic options remain limited to antibiotics, with no other efficacious alternatives available. Echinatin (Ecn), a potent bioactive compound extracted from the roots and rhizomes of licorice, has gained significant attention for its broad pharmacological properties, particularly its ability to combat oxidative stress. Recent research highlights the crucial role that oxidative stress plays in the onset and progression of sepsis further emphasizing the potential therapeutic value of Ecn in this context. In this study, we explored the protective effects of Ecn in a murine model of sepsis induced by cecal ligation and puncture (CLP). Ecn demonstrated a significant reduction in the levels of inflammatory cytokines and reactive oxygen species (ROS) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Network pharmacology analysis identified 41 targets and top 15 pathways involved in the Ecn-mediated signaling network, revealing that Ecn might exert its effects through key targets including the NF-κB and MAPK signaling pathways. Molecular docking studies suggested a strong affinity between Ecn and MEK, with kinetic simulations and binding energy calculations confirming a stable interaction. Mechanistically, Ecn treatment inhibited NF-κB and the MEK/ERK signaling pathway, as evidenced by decreased phosphorylation of IκBα and nuclear p65, along with reduced phosphorylation of MEK and ERK in both LPS-stimulated RAW 264.7 macrophages and septic mice. Furthermore, the administration of MEK signaling agonists reversed the anti-inflammatory effects of Ecn, indicating the involvement of this signaling pathway in Ecn's protective mechanism. Notably, our investigation revealed that Ecn did not affect bacterial proliferation either in vivo or in vitro, underscoring its specific immunomodulatory effects rather than direct antimicrobial activity. In summation, our findings underscored the potential of Ecn as an innovative therapeutic remedy for sepsis-induced injury, particularly through the regulation of the NF-κB and MEK/ERK signaling pathway. This exploration unveiled a promising therapeutic approach for treating sepsis, supplementing existing interventions and addressing their constraints.

Mir22hg facilitates ferritinophagy-mediated ferroptosis in sepsis by recruiting the m6A reader YTHDC1 and enhancing Angptl4 mRNA stability

BACKGROUND

Ferritinophagy-mediated ferroptosis plays a crucial role in fighting pathogen aggression. The long non-coding RNA Mir22hg is involved in the regulation of ferroptosis and aberrantly overexpression in lipopolysaccharide (LPS)-induced sepsis mice, but whether it regulates sepsis through ferritinophagy-mediated ferroptosis is unclear.

METHODS

Mir22hg was screened by bioinformatics analysis. Ferroptosis was assessed by assaying malondialdehyde (MDA), reactive oxygen species (ROS), and Fe2+ levels, glutathione (GSH) activity, as well as ferroptosis-related proteins GPX4 and SLC3A2 by using matched kits and performing western blot. Ferritinophagy was assessed by Lyso tracker staining and FerroOrange staining, immunofluorescence analysis of Ferritin and LC-3, and western blot analysis of LC-3II/I, p62, FTH1, and NCOA4. The bind of YTH domain containing 1 (YTHDC1) to Mir22hg or angiopoietin-like-4 (Angptl4) was verified by RNA pull-down and/or immunoprecipitation (RIP) assays.

RESULTS

Mir22hg silencing lightened ferroptosis and ferritinophagy in LPS-induced MLE-12 cells and sepsis mouse models, as presented by the downregulated MDA, ROS, Fe2+, NCOA4, and SLC3A2 levels, upregulated GPX4, GSH, and FTH1 levels, along with a decrease in autophagy. Mir22hg could bind to the m6A reader YTHDC1 without affecting its expression. Mechanistically, Mir22hg enhanced Angptl4 mRNA stability through recruiting the m6A reader YTHDC1. Furthermore, Angptl4 overexpression partly overturned Mir22hg inhibition-mediated effects on ferroptosis and ferritinophagy in LPS-induced MLE-12 cells.

CONCLUSION

Mir22hg contributed to in ferritinophagy-mediated ferroptosis in sepsis via recruiting the m6A reader YTHDC1 and strengthening Angptl4 mRNA stability, highlighting that Mir22hg may be a potential target for sepsis treatment based on ferroptosis.

Peroxiredoxin 3 regulates breast cancer progression via ERK-mediated MMP-1 expression

Peroxiredoxin 3 (PRDX3), a mitochondrial hydrogen peroxide scavenger, is known to be upregulated during tumorigenesis and cancer progression. In this study, we provide evidence for the first time that PRDX3 could regulate cellular signaling pathways associated with Matrix Metalloproteinase-1 (MMP-1) expression and activity in breast cancer progression. We show that shRNA-mediated gene silencing of PRDX3 inhibits cell migration and invasion in two triple-negative breast cancer cell lines. Reciprocal experiments show that PRDX3 overexpression promotes invasion and migration of the cancer cells, processes which are important in the metastatic cascade. Notably, this phenomenon may be attributed to the activation of MMP-1, which is observed to be upregulated by PRDX3 in the breast cancer cells. Moreover, immunohistochemical staining of breast cancer tissues revealed a positive correlation between PRDX3 and MMP-1 expression in both epithelial and stromal parts of the tissues. Further pathway reporter array and luciferase assay demonstrated that activation of ERK signaling is responsible for the transcriptional activation of MMP-1 in PRDX3-overexpressed cells. These findings suggest that PRDX3 could mediate cancer spread via ERK-mediated activation of MMP-1. Targeted inhibition of ERK signaling may be able to inhibit tumor metastasis in triple-negative breast cancer.

CryoGrid-PIXUL-RNA: high throughput RNA isolation platform for tissue transcript analysis

BACKGROUND

Disease molecular complexity requires high throughput workflows to map disease pathways through analysis of vast tissue repositories. Great progress has been made in tissue multiomics analytical technologies. To match the high throughput of these advanced analytical platforms, we have previously developed a multipurpose 96-well microplate sonicator, PIXUL, that can be used in multiple workflows to extract analytes from cultured cells and tissue fragments for various downstream molecular assays. And yet, the sample preparation devices, such as PIXUL, along with the downstream multiomics analytical capabilities have not been fully exploited to interrogate tissues because storing and sampling of such biospecimens remain, in comparison, inefficient.

RESULTS

To mitigate this tissue interrogation bottleneck, we have developed a low-cost user-friendly system, CryoGrid, to catalog, cryostore and sample tissue fragments. TRIzol is widely used to isolate RNA but it is labor-intensive, hazardous, requires fume-hoods, and is an expensive reagent. Columns are also commonly used to extract RNA but they involve many steps, are prone to human errors, and are also expensive. Both TRIzol and column protocols use test tubes. We developed a microplate PIXUL-based TRIzol-free and column-free RNA isolation protocol that uses a buffer containing proteinase K (PK buffer). We have integrated the CryoGrid system with PIXUL-based PK buffer, TRIzol, and PureLink column methods to isolate RNA for gene-specific qPCR and genome-wide transcript analyses. CryoGrid-PIXUL, when integrated with either PK buffer, TRIzol or PureLink column RNA isolation protocols, yielded similar transcript profiles in frozen organs (brain, heart, kidney and liver) from a mouse model of sepsis.

CONCLUSIONS

RNA isolation using the CryoGrid-PIXUL system combined with the 96-well microplate PK buffer method offers an inexpensive user-friendly high throughput workflow to study transcriptional responses in tissues in health and disease as well as in therapeutic interventions.

Psilocin suppresses methamphetamine-induced hyperlocomotion and acquisition of conditioned place preference via D2R-mediated ERK signaling

AIM

Psilocin is an active metabolite form of psilocybin and exerts psychoactive effects. Recent studies suggest that psilocin may have regulatory effects on abuse drugs, but the mechanisms remain unclear. In this study, we want to explore the effects of psilocin on methamphetamine (METH)-induced alterations of behavior in mice and its molecular mechanisms.

METHODS

Acute METH administration model and conditioned place preference (CPP) model were used to investigate the effects of psilocin on METH-induced alterations of behavior. Western blot was used to detect the expression of proteins.

RESULTS

In the acute 2 mg/kg METH administration model, 1 mg/kg psilocin counteracted METH-induced elevation of activity. In the 1 mg/kg METH-induced CPP model, 1 mg/kg psilocin inhibited CPP formation during the acquisition phase. However, psilocin did not impact METH extinction and relapse. Molecular results showed that the regulatory effect of psilocin on METH was underscored by altered expression of dopamine 2 receptor (D2R) and phosphorylated extra-cellular signal-regulated kinase (p-ERK) in the prefrontal cortex (PFC), nucleus accumbens (NAc), and ventral tegmental area (VTA). Trifluoperazine (TFP)-2HCl is a D2R inhibitor, and SCH772984 is a selective extra-cellular signal-regulated kinase (ERK) inhibitor that effectively inhibits ERK1/2 phosphorylation. The results indicated that 2 mg/kg TFP-2HCl and 10 mg/kg SCH772984 blocked METH-induced hyperactivity and acquisition of METH-induced CPP.

CONCLUSION

Psilocin has regulatory effects on METH-induced alterations of behavior in mice via D2R-mediated signal regulation of ERK phosphorylation.

Lactiplantibacillus plantarum LOC1 Isolated from Fresh Tea Leaves Modulates Macrophage Response to TLR4 Activation

Previously, we demonstrated that Lactiplantibacillus plantarum LOC1, originally isolated from fresh tea leaves, was able to improve epithelial barrier integrity in in vitro models, suggesting that this strain is an interesting probiotic candidate. In this work, we aimed to continue characterizing the potential probiotic properties of the LOC1 strain, focusing on its immunomodulatory properties in the context of innate immunity triggered by Toll-like receptor 4 (TLR4) activation. These studies were complemented by comparative and functional genomics analysis to characterize the bacterial genes involved in the immunomodulatory capacity. We carried out a transcriptomic study to evaluate the effect of L. plantarum LOC1 on the response of murine macrophages (RAW264.7 cells) to the activation of TLR4. We demonstrated that L. plantarum LOC1 exerts a modulatory effect on lipopolysaccharide (LPS)-induced inflammation, resulting in a differential regulation of immune factor expression in macrophages. The LOC1 strain markedly reduced the LPS-induced expression of some inflammatory cytokines (IL-1β, IL-12, and CSF2) and chemokines (CCL17, CCL28, CXCL3, CXCL13, CXCL1, and CX3CL1), while it significantly increased the expression of other cytokines (TNF-α, IL-6, IL-18, IFN-β, IFN-γ, and CSF3), chemokines (IL-15 and CXCL9), and activation markers (H2-k1, H2-M3, CD80, and CD86) in RAW macrophages. Our results show that L. plantarum LOC1 would enhance the intrinsic functions of macrophages, promoting their protective effects mediated by the stimulation of the Th1 response without affecting the regulatory mechanisms that help control inflammation. In addition, we sequenced the LOC1 genome and performed a genomic characterization. Genomic comparative analysis with the well-known immunomodulatory strains WCSF1 and CRL1506 demonstrated that L. plantarum LOC1 possess a set of adhesion factors and genes involved in the biosynthesis of teichoic acids and lipoproteins that could be involved in its immunomodulatory capacity. The results of this work can contribute to the development of immune-related functional foods containing L. plantarum LOC1.

Oncology Drug Repurposing for Sepsis Treatment

Sepsis involves life-threatening organ dysfunction caused by a dysregulated host response to infection. Despite three decades of efforts and multiple clinical trials, no treatment, except antibiotics and supportive care, has been approved for this devastating syndrome. Simultaneously, numerous preclinical studies have shown the effectiveness of oncology-indicated drugs in ameliorating sepsis. Here we focus on cataloging these efforts with both oncology-approved and under-development drugs that have been repositioned to treat bacterial-induced sepsis models. In this context, we also envision the exciting prospect for further standard and oncology drug combination testing that could ultimately improve clinical outcomes in sepsis.