Blocking Cyclic Adenosine Diphosphate Ribose-mediated Calcium Overload Attenuates Sepsis-induced Acute Lung Injury in Rats

Focus on the role of calcium signaling in ferroptosis: a potential therapeutic strategy for sepsis-induced acute lung injury

By engaging in redox processes, ferroptosis plays a crucial role in sepsis-induced acute lung injury (ALI). Although iron stimulates calcium signaling through the stimulation of redox-sensitive calcium pathways, the function of calcium signals in the physiological process of ferroptosis in septic ALI remains unidentified. Iron homeostasis disequilibrium in ferroptosis is frequently accompanied by aberrant calcium signaling. Intracellular calcium overflow can be a symptom of dysregulation of the cellular redox state, which is characterized by iron overload during the early phase of ferroptosis. This can lead to disruptions in calcium homeostasis and calcium signaling. The mechanisms controlling iron homeostasis and ferroptosis are reviewed here, along with their significance in sepsis-induced acute lung injury, and the potential role of calcium signaling in these processes is clarified. We propose that the development of septic acute lung injury is a combined process involving the bidirectional interaction between iron homeostasis and calcium signaling. Our goal is to raise awareness about the pathophysiology of sepsis-induced acute lung injury and investigate the relationship between these mechanisms and ferroptosis. We also aimed to develop calcium-antagonistic therapies that target ferroptosis in septic ALI and improve the quality of survival for patients suffering from acute lung injury.

A Melanin-like Nanoenzyme for Acute Lung Injury Therapy via Suppressing Oxidative and Endoplasmic Reticulum Stress Response

Nanoenzyme-mediated catalytic activity is emerging as a novel strategy for reactive oxygen species (ROS) scavenging in acute lung injury (ALI) treatment. However, one of the main hurdles for these metal-containing nanoenzymes is their potential toxicity and single therapeutic mechanism. Herein, we uncovered a melanin-like nanoparticles derived from the self-polymerization of 1,8-dihydroxynaphthalene (PDH nanoparticles), showing a significant anti-inflammation therapeutic effect on ALI mice. The prepared PDH nanoparticles rich in phenol groups could not only act as radical scavengers to alleviate oxidative stress but could also chelate calcium overload to suppress the endoplasmic reticulum stress response. As revealed by the therapeutic effect in vivo, PDH nanoparticles significantly prohibited neutrophil infiltration and the secretion of proinflammatory cytokines (TNF-α and IL-6), thus improving the inflammatory cascade in the ALI model. Above all, our work provides an effective anti-inflammatory nanoplatform by using the inherent capability of melanin-like nanoenzymes, proposing the potential application prospects of these melanin-like nanoparticles for acute inflammation-induced injury treatment.

miR-128-3p enhances the protective effect of dexmedetomidine on acute lung injury in septic mice by targeted inhibition of MAPK14

To investigate the role of miR-128-3p and MAPK14 in the dexmedetomidine treatment of acute lung injury in septic mice. SPF C57BL/6 mice were divided into 8 groups. The pathological changes and wet/dry weight ratio (W/D), PaO₂, PaCO₂, MDA, SOD and MPO levels in lung tissue and the serum levels of inflammation factors were observed. Dual luciferase reporter assay was used to detect the targeting relationship of miR-128-3p and MAPK14, and qPCR and WB were used to detect the expression of miR-128-3p and MAPK14. Compared with the Normal group, other groups had lower MDA, MPO, inflammatory factors levels and the expression level of MAPK14, while the content of SOD and the expression level of miR-128-3p was significantly decreased (all p < 0.05). Compared with the Model group, the contents of MDA, MPO, inflammatory factors in the DEX group and miR-128-3p mimic group were significantly decreased, and the content SOD was significantly increased, however, opposite results were occurred in oe-MAPK14 group (all p < 0.05). Compared with the DEX group, all the indicators in miR-128-3p mimic+DEX group showed significant improvement (all p < 0.05). Compared with the miR-128-3p mimic group, all the indicators were deteriorated in the miR-128-3p mimic+oe-MAPK14 group (all p < 0.05). The combination of DEX and oe-MAPK14 blocked the protective effect of dexmedetomidine on acute lung injury in septic mice. miR-128-3p can further enhance the protective effect of dexmedetomidine on acute lung injury in septic mice by targeting and inhibiting MAPK14 expression.

The protective effects of angiotensin-converting enzyme inhibitor against cecal ligation and puncture-induced sepsis via oxidative stress and inflammation

AIMS

Sepsis is a severe public health problem affecting millions of individuals, with global mortality rates caused by lower respiratory tract infections are approximately 2.38 million people a year die from respiratory failure caused by infection. Although ACE is known to contribute to damage in septicemia, the pathophysiological mechanisms of sepsis remain unclear. While mortality can be significantly reduced through effective and sensitive antibiotic therapy, antibiotic resistance restricts the use of these drugs, and the investigation of novel agents and targets is therefore essential. Our aim was to determine whether Perindopril (PER) has anti-inflammatory and antioxidant capable of preventing these adverse conditions resulting in injury in previous studies.

MAIN METHODS

Sprague Dawley rats were randomly assigned into the control group, received oral saline solution alone for four days. the cecal ligation and puncture (CLP) group, underwent only cecal ligation and puncture induced sepsis, while the CLP + PER (2 mg/kg) underwent cecal ligation and puncture-induced sepsis together with oral administration of 2 mg/kg PER for four days before induction of sepsis.

KEY FINDINGS

Malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), Caspase-3 and nuclear factor kappa B (NF-kβ/p65) levels increased in the CLP group. On the other hand, PER (2 mg/kg) oral administration to septic rats decreased MDA, TNF-α and increase glutathione (GSH) in the lung tissue. In addition, PER administration also decreased the lung tissue NF-κB and Caspase-3 immunopositivity against sepsis.

SIGNIFICANCE

PER treatment may represent a promising means of preventing sepsis-induced lung injury via antioxidant and anti-inflammation effects.

Increased TLR4 Expression Aggravates Sepsis by Promoting IFN-γ Expression in CD38-/- Mice

Gram-negative bacterial sepsis accounts for up to 50% worldwide sepsis that causes hospital mortality. Acute kidney injury (AKI), a common complication of Gram-negative bacterial sepsis, is caused by Toll-like receptor 4 (TLR4) activation. Lipopolysaccharide (LPS) is an endotoxin in Gram-negative bacteria and is recognized specifically by TLR4, which initiates innate immune response. Also, TLR4 signaling pathway activation is essential in response to LPS infection. CD38 is one of the well-known regulators of innate immunity, whose dysregulation contributes to sepsis. Many studies have proven that an attenuated Gram-positive bacterium induces sepsis in a CD38-blocking model. However, the pathogenesis of Gram-negative bacteria-induced sepsis in a CD38^−/− mouse model remains unclear. The aim of this study is to investigate whether kidney injury is still attenuated in a LPS-induced CD38^−/− sepsis model and identify the potential mechanism. We assess the severity of kidney injury related to proinflammatory cytokine expressions (IFN-γ, TNF-α, IL-1β, and IL-6) in WT and CD38^−/− mice. Our results showed more aggravated kidney damage in CD38^−/− mice than in WT mice, accompanied with an increase of proinflammatory cytokine expression. In addition, compared with CD38^−/−TLR4^mut mice, we found an increase of TLR4 expression and mRNA expression of these cytokines in the kidney of CD38^−/− mice, although only increased IFN-γ level was detected in the serum. Taken together, these results demonstrated that an increased TLR4 expression in CD38^−/− mice could contribute to the aggravation of AKI through boosting of the production of IFN-γ.

CD38 in the pathogenesis of allergic airway disease: Potential therapeutic targets

CD38 is an ectoenzyme that catalyzes the conversion of β-nicotinamide adenine dinucleotide (β-NAD) to cyclic adenosine diphosphoribose (cADPR) and adenosine diphosphoribose (ADPR) and NADP to nicotinic acid adenine dinucleotide phosphate (NAADP) and adenosine diphosphoribose-2'-phosphate (ADPR-P). The metabolites of NAD and NADP have roles in calcium signaling in different cell types including airway smooth muscle (ASM) cells. In ASM cells, inflammatory cytokines augment CD38 expression and to a greater magnitude in cells from asthmatics, indicating a greater capacity for the generation of cADPR and ADPR in ASM from asthmatics. CD38 deficient mice develop attenuated airway responsiveness to inhaled methacholine following allergen sensitization and challenge compared to wild-type mice indicating its potential role in asthma. Regulation of CD38 expression in ASM cells is achieved by mitogen activated protein kinases, specific isoforms of PI3 kinases, the transcription factors NF-κB and AP-1, and post-transcriptionally by microRNAs. This review will focus on the role of CD38 in intracellular calcium regulation in ASM, contribution to airway inflammation and airway hyperresponsiveness in mouse models of allergic airway inflammation, the transcriptional and post-transcriptional mechanisms of regulation of expression, and outline approaches to inhibit its expression and activity.