Interleukin-5 deletion promotes sepsis-induced M1 macrophage differentiation, deteriorates cardiac dysfunction, and exacerbates cardiac injury via the NF-κB p65 pathway in mice

Homer1a reduces inflammatory response after retinal ischemia/reperfusion injury

JOURNAL/nrgr/04.03/01300535-202407000-00042/figure1/v/2023-11-20T171125Z/r/image-tiff

Elevated intraocular pressure (IOP) is one of the causes of retinal ischemia/reperfusion injury, which results in NLRP3 inflammasome activation and leads to visual damage. Homer1a is reported to play a protective role in neuroinflammation in the cerebrum. However, the effects of Homer1a on NLRP3 inflammasomes in retinal ischemia/reperfusion injury caused by elevated IOP remain unknown. In our study, animal models were constructed using C57BL/6J and Homer1flox/ –/Homer1a+/ –/Nestin-Cre+/ – mice with elevated IOP-induced retinal ischemia/reperfusion injury. For in vitro experiments, the oxygen-glucose deprivation/reperfusion injury model was constructed with Müller cells. We found that Homer1a overexpression ameliorated the decreases in retinal thickness and Müller cell viability after ischemia/reperfusion injury. Furthermore, Homer1a knockdown promoted NF-κB P65Ser536 activation via caspase-8, NF-κB P65 nuclear translocation, NLRP3 inflammasome formation, and the production and processing of interleukin-1β and interleukin-18. The opposite results were observed with Homer1a overexpression. Finally, the combined administration of Homer1a protein and JSH-23 significantly inhibited the reduction in retinal thickness in Homer1flox/ –/Homer1a+/ –/Nestin-Cre+/ – mice and apoptosis in Müller cells after ischemia/reperfusion injury. Taken together, these studies demonstrate that Homer1a exerts protective effects on retinal tissue and Müller cells via the caspase-8/NF-κB P65/NLRP3 pathway after I/R injury.

Pretreatment with interleukin-15 attenuates inflammation and apoptosis by inhibiting NF-κB signaling in sepsis-induced myocardial dysfunction

Sepsis-induced myocardial dysfunction (SIMD) is associated with poor prognosis and increased mortality in patients with sepsis. Cytokines are important regulators of both the initiation and progression of sepsis. Interleukin-15 (IL-15), a pro-inflammatory cytokine, has been linked to protective effects against myocardial infarction and myocarditis. However, the role of IL-15 in SIMD remains unclear. We established a mouse model of SIMD via cecal ligation puncture (CLP) surgery and a cell model of myocardial injury via lipopolysaccharide (LPS) stimulation. IL-15 expression was prominently upregulated in septic hearts as well as cardiomyocytes challenged with LPS. IL-15 pretreatment attenuated cardiac inflammation and cell apoptosis and improved cardiac function in the CLP model. Similar cardioprotective effects of IL-15 pretreatment were observed in vitro. As expected, IL-15 knockdown had the opposite effect on LPS-stimulated cardiomyocytes. Mechanistically, we found that IL-15 pretreatment reduced the expression of the pro-apoptotic proteins cleaved caspase-3 and Bax and upregulated the anti-apoptotic protein Bcl-2. RNA sequencing and Western blotting further confirmed that IL-15 pretreatment suppressed the activation of nuclear factor kappa B (NF-κB) signaling in mice with sepsis. Besides, the addition of NF-κB inhibitor can significantly attenuate cardiomyocyte apoptosis compared to the control findings. Our results suggest that IL-15 pretreatment attenuated the cardiac inflammatory responses and reduced cardiomyocyte apoptosis by partially inhibiting NF-κB signaling in vivo and in vitro, thereby improving cardiac function in mice with sepsis. These findings highlight a promising therapeutic strategy for SIMD.

Comprehensive analysis the diagnosis, malignant progression and immune infiltrate of ANXA6 in prostate cancer

BACKGROUND

Annexins (ANXAs) play a crucial role in the development and progression of tumors. However, their specific involvement in prostate cancer (PCa) remains unclear.

OBJECTIVE

To investigate the function and clinical significance of key ANXAs in PCa.

METHODS

Multiple databases were used to analyze the expression levels, genetic variations, potential prognostic value and clinical significance of ANXAs in PCa. Then, the co-expressed genes of ANXA6 were identified, and the correlation between ANXA6 and immune cell infiltration was validated using the Tumor Immune Estimation Resource (TIMER) database. Additionally, in vitro assays such as Cell Counting Kit-8 (CCK-8), Colony Formation, Transwell and T-cell Chemotaxis assays were conducted to validate the functions of ANXA6. Moreover, multiple types of in vivo assays were performed to further validate the identified ANXA6 functions.

RESULTS

The results demonstrated that ANXA2, ANXA6 and ANXA8 were significantly downregulated in PCa. ANXA6 upregulation was significantly associated with improved PCa patients' overall survival. Enrichment analysis revealed that ANXA6 and its co-expressed genes were involved in tumor progression, and ANXA6 overexpression could effectively inhibit the proliferation, migration and invasion of PC-3 cells. In vivo studies also demonstrated that ANXA6 overexpression suppressed tumor growth. Importantly, ANXA6 was found to promote the chemotaxis of CD4+ T cells and CD8+ T cells towards PC-3 cells, and the overexpression of ANXA6 in PC-3 cells promoted the polarization of macrophages into M1 macrophages in the supernatant of PCa cells.

CONCLUSIONS

ANXA6 demonstrated promising potential for consideration as a prognostic biomarker in PCa as it was found to play key roles in regulating immune cell infiltration and the malignant progression to PCa.

Inflammatory mechanisms and intervention strategies for sepsis-induced myocardial dysfunction

Sepsis-induced myocardial dysfunction (SIMD) is the leading cause of death in patients with sepsis in the intensive care units. The main manifestations of SIMD are systolic and diastolic dysfunctions of the myocardium. Despite our initial understanding of the SIMD over the past three decades, the incidence and mortality of SIMD remain high. This may be attributed to the large degree of heterogeneity among the initiating factors, disease processes, and host states involved in SIMD. Previously, organ dysfunction caused by sepsis was thought to be an impairment brought about by an excessive inflammatory response. However, many recent studies have shown that SIMD is a consequence of a combination of factors shaped by the inflammatory responses between the pathogen and the host. In this article, we review the mechanisms of the inflammatory responses and potential novel therapeutic strategies in SIMD.

The CaSR/TRPV4 coupling mediates pro-inflammatory macrophage function

AIM

Although calcium-sensing receptor (CaSR) and transient receptor potential vanilloid 4 (TRPV4) channels are functionally expressed on macrophages, it is unclear if they work coordinately to mediate macrophage function. The present study investigates whether CaSR couples to TRPV4 channels and mediates macrophage polarization via Ca²⁺ signaling.

METHODS

The role of CaSR/TRPV4/Ca²⁺ signaling was assessed in lipopolysaccharide (LPS)-treated peritoneal macrophages (PMs) from wild-type (WT) and TRPV4 knockout (TRPV4 KO) mice. The expression and function of CaSR and TRPV4 in PMs were analyzed by immunofluorescence and digital Ca²⁺ imaging. The correlation factors of M1 polarization, CCR7, IL-1β, and TNFα were detected using q-PCR, western blot, and ELISA.

RESULTS

We found that PMs expressed CaSR and TRPV4, and CaSR activation-induced marked Ca²⁺ signaling predominately through extracellular Ca²⁺ entry, which was inhibited by selective pharmacological blockers of CaSR and TRPV4 channels. The CaSR activation-induced Ca²⁺ signaling was significantly attenuated in PMs from TRPV4 KO mice compared to those from WT mice. Moreover, the CaSR activation-induced Ca²⁺ entry via TRPV4 channels was inhibited by blocking phospholipases A2 (PLA2)/cytochromeP450 (CYP450) and phospholipase C (PLC)/Protein kinase C (PKC) pathways. Finally, CaSR activation promoted the expression and release of M1-associated cytokines IL-1β and TNFɑ, which were attenuated in PMs from TRPV4 KO mice.

CONCLUSION

We reveal a novel coupling of the CaSR and TRPV4 channels via PLA2/CYP450 and PLC/PKC pathways, promoting a Ca²⁺ -dependent M1 macrophage polarization. Modulation of this coupling and downstream pathways may become a potential strategy for the prevention/treatment of immune-related disease.

Macrophage-Derived Exosomes in TLR9-/- Mice Ameliorate Sepsis-Induced Mitochondrial Oxidative Stress and Apoptosis in Cardiomyocytes

Objective

To explore the mechanisms of TLR9 from macrophages on mitochondrial apoptosis in cardiomyocytes at early stage of sepsis.

Methods

The in vivo and in vitro sepsis mice were bone marrow transplantation (BMT) with wild type (WT) or (toll-like receptor 9) TLR9 knockout (^−/− or KO) myeloid cells and then constructed by cecum ligation and puncture (CLP) as vivo experiment and cardiomyocytes cocultured with WT or TLR9-deficient macrophages treated with LPS as vitro experiment, respectively. Sepsis model were performed by CLP. The expression levels of exosome, PI3K/AKT, and ERK1/2, inflammatory factors, and apoptotic proteins were tested by western blot in vivo. Besides, associated apoptotic proteins and JC-1 fluorescence assay were tested in vitro.

Results

The expressions of p-PI3K, p-AKT, exosome markers (CD9, CD63, and TSG101), p-ERK1/2, TNF-α, IFN-γ, IL-1β, and cleaved-caspase-3/-9 were significantly increased in septic mice vs. control mice, and these proteins were declined dramatically in TLR9^−/− BMT mice vs. WT BMT mice in sepsis mice models. Meanwhile, the protein expression of cytochrome C, cleaved-caspase-3, and cleaved-caspase-9 increased significantly in primary mouse myocardial cells cocultured with TLR9^−/− or WT macrophages stimulated with LPS, and these mitochondrial apoptotic proteins as well as the green 5,5',6,6'-tetrachloro-1,1',3,3'- tetraethylbenzimidazolcarbocyanine iodide (JC-1) fluorescence were dramatically lower in LPS-stimulated cardiomyocytes cocultured with TLR9^−/− than with WT macrophages.

Conclusion

TLR9^−/− in macrophages suppressed the inflammatory reaction as well as the exosome secretion and resulted in the inhibition of apoptosis and oxidative stress in sepsis-induced cardiomyopathy.

Vaspin Alleviates Sepsis-Induced Cardiac Injury and Cardiac Inflammation by Inhibiting Kallikrein 7 in Mice

Background

Vaspin is an important adipokine that is involved in cardiovascular diseases. This study is aimed at investigating whether vaspin participates in sepsis-induced cardiac injury and explored the possible mechanism.

Methods

First, cecal ligation and puncture (CLP) and lipopolysaccharide (LPS) were used to establish a mouse model of sepsis, and cardiac vaspin expression was examined. In addition, after pretreatment with vaspin or phosphate-buffered saline (PBS), wild-type (WT) mice underwent CLP to establish a septic model and received sham as a control. Finally, WT mice and kallikrein 7 (KLK7-/-) mice were underwent CLP with or without vaspin pretreatment.

Results

Mice that underwent CLP and were administered LPS exhibited increased vaspin expression in both the heart and serum compared with sham- or saline-treated mice. In CLP mice, pretreatment with vaspin reduced mortality and alleviated the expression of cardiac injury markers and cardiac dysfunction. In addition, vaspin reduced the cardiac levels of CD45+ cells and CD68+ cells, alleviated the cardiac inflammatory response, and reduced cardiomyocyte apoptosis. The protective effects of vaspin on CLP mice were masked by the deletion of KLK7, which was demonstrated to be a downstream signal of vaspin.

Conclusions

Vaspin alleviates cardiac inflammation and plays a protective role in sepsis-induced cardiac injury by reducing KLK7 expression.

Inflammatory mediators of cytokines and chemokines in sepsis: From bench to bedside

Background: Sepsis is a serious clinical condition characterized by damage to the immune system as a result of an uncontrolled response to infection. Septic patients show complications such as fever, cardiovascular shock, and/or systemic organ failure. Acute organ failure formed in sepsis mostly affects the respiratory and cardiovascular systems. In sepsis, responses including pro-inflammatory and anti-inflammatory processes in addition to the Toll-Like Receptor 4 (TLR4) signals leading to the release of inflammatory mediators have been suggested to be fundamental pathways in the pathophysiology of sepsis. Purpose: In this context, unregulated levels of sepsis-associated inflammatory mediators may increase the risk of mortality. In sepsis, infection-induced pathogens lead to a systemic inflammatory response. These systemic responses may contribute to septic shock and organ dysfunction. In the unfavorable clinical course of sepsis, an uncontrolled inflammatory response is observed. Accordingly, the mechanism of inflammatory mediators such as cytokines and chemokines in sepsis might increase. Neurotransmitters and gene regulators affect inflammatory mediators and control the inflammatory response. In this review, we aimed to show the new therapeutic targets in sepsis treatment with current studies. New clinical implications targeting inflammatory mediators in high mortality affected by the uncontrolled inflammatory response in sepsis can contribute to the understanding of the symptoms.

Butorphanol alleviates lipopolysaccharide-induced inflammation and apoptosis of cardiomyocytes via activation of the κ-opioid receptor

Sepsis-induced myocardial dysfunction is a leading cause of the high mortality rates associated with sepsis. The aim of the present study was to investigate the effect of butorphanol on sepsis-induced cardiomyocyte dysfunction. Lipopolysaccharide (LPS) was used to induce H9C2 cardiomyocytes to establish an in vitro sepsis model. The effect of butorphanol on the viability of LPS-induced H9C2 cells was analyzed using a Cell Counting Kit-8 assay. The levels of tumor necrosis factor-α, interleukin (IL)-1β and IL-6 were detected using ELISA. Western blotting was used to analyze the expression levels of inflammation-and apoptosis-related proteins. Cell apoptosis was measured using a TUNEL assay. The expression levels of κ-opioid receptor (KOR) were analyzed using reverse transcription-quantitative PCR analysis and western blotting. Following LPS induction, the levels of inflammatory cytokines and proapoptotic proteins were found to be upregulated in H9C2 cells, while butorphanol treatment downregulated these levels. The expression levels of KOR were also upregulated following butorphanol treatment in LPS-induced H9C2 cells. Addition of the KOR inhibitor, nor-binaltorphimine, alleviated the inhibitory effects of butorphanol on inflammation and apoptosis in LPS-induced H9C2 cells. In conclusion, the findings of the present study provided evidence indicating that butorphanol may alleviate LPS-induced inflammation and apoptosis in cardiomyocytes by upregulating KOR expression, which may provide a novel insight into the potential therapeutic effects of butorphanol and its underlying mechanism of action.