JNK signaling is required for the MIP‑1α‑associated regulation of Kupffer cells in the heat stroke response

Physiological and Psychological Stress of Microwave Radiation-Induced Cardiac Injury in Rats

Electromagnetic waves are widely used in both military and civilian fields, which could cause long-term and high-power exposure to certain populations and may pose a health hazard. The aim of this study was to simulate the long-term and high-power working environment of workers using special electromagnetic radiation occupations to clarify the radiation-induced stress response and cardiac damage and thus gain insights into the mechanisms of injuries caused by electromagnetic radiation. In this study, the combination of microwave and stress was an innovative point, aiming to broaden the research direction with regard to the effect and mechanism of cardiac injury caused by radiation. The myocardial structure was observed by optical and transmission electron microscope, mitochondrial function was detected by flow cytometry, oxidative-stress markers were detected by microplate reader, serum stress hormone was detected by radioimmunoassay, and heart rate variability (HRV) was analyzed by multichannel-physiological recorder. The rats were weighed and subjected to an open field experiment. Western blot (WB) and immunofluorescence (IF) were used to detect the expressions and distributions of JNK (c-Jun N-terminal kinase), p-JNK (phosphorylated c-Jun N-terminal kinase), HSF1 (heat shock factor), and NFATc4 (nuclear factor of activated T-cell 4). This study found that radiation could lead to the disorganization, fragmentation, and dissolution of myocardial fibers, severe mitochondrial cavitation, mitochondrial dysfunction, oxidative-stress injury in myocardium, increase to stress hormone in serum, significant changes in HRV, and a slow gain in weight. The open field experiment indicated that the rats experienced anxiety and depression and had decreased exercise capacity after radiation. The expressions of JNK, p-JNK, HSF1, and NFATc4 in myocardial tissue were all increased. The above results suggested that 30 mW/cm2 of S-band microwave radiation for 35 min could cause both physiological and psychological stress damage in rats; the damage was related to the activation of the JNK pathway, which provided new ideas for research on protection from radiation.

Alteration of gut microbiota after heat acclimation may reduce organ damage by regulating immune factors during heat stress

Introduction

Heat-related illnesses can lead to morbidity, which are anticipated to increase frequency with predictions of increased global surface temperatures and extreme weather events. Although heat acclimation training (HAT) could prevent heat-related diseases, the mechanisms underlying HAT-promoting beneficial changes in organ function, immunity, and gut microbes remain unclear.

Methods

In the current study, we recruited 32 healthy young soldiers and randomly divided them into 4 teams to conduct HATs for 10 days: the equipment-assisted training team at high temperature (HE); the equipment-assisted training team under normal hot weather (NE); the high-intensity interval training team at high temperature (HIIT), and the control team without training. A standard heat tolerance test (HTT) was conducted before (HTT-1st) and after (HTT-2nd) the training to judge whether the participants met the heat acclimation (HA) criteria.

Results

We found that the participants in both HE and NE teams had significantly higher acclimation rates (HA/total population) than whom in the HIIT team. The effects of HAT on the participants of the HE team outperformed that of the NE team. In the HA group, the differences of physiological indicators and plasma organ damage biomarkers (ALT, ALP, creatinine, LDH, α-HBDH and cholinesterase) before and after HTT-2nd were significantly reduced to those during HTT-1st, but the differences of immune factors (IL-10, IL-6, CXCL2, CCL4, CCL5, and CCL11) elevated. The composition, metabolism, and pathogenicity of gut microbes changed significantly, with a decreased proportion of potentially pathogenic bacteria (Escherichia-Shigella and Lactococcus) and increased probiotics (Dorea, Blautia, and Lactobacillus) in the HA group. Training for a longer time in a high temperature and humidity showed beneficial effects for intestinal probiotics.

Conclusion

These findings revealed that pathogenic gut bacteria decrease while probiotics increase following HA, with elevated immune factors and reduced organ damage during heat stress, thereby improving the body's heat adaption.

The pathogenesis and therapeutic strategies of heat stroke-induced liver injury

Heat stroke (HS) is a life-threatening systemic disease characterized by an elevated core body temperature of more than 40 ℃ and subsequent multiple organ dysfunction syndrome. With the growing frequency of global heatwaves, the incidence rate of HS has increased significantly, which has caused a huge burden on people's lives and health. Liver injury is a well-documented complication of HS and usually constitutes the direct cause of patient death. In recent years, a lot of research has been carried out on the pathogenesis and treatment strategies of HS-induced liver injury. In this review, we summarized the important pathogenesis of HS-induced liver injury that has been confirmed so far. In addition to the comprehensive effect of systemic factors such as heat cytotoxicity, coagulopathy, and systemic inflammatory response syndrome, excessive hepatocyte cell pyroptosis, dysfunction of Kupffer cells, abnormal expression of heat shock protein expression, and other factors are also involved in the pathogenesis of HS-induced liver injury. Furthermore, we have also established the current therapeutic strategies for HS-induced liver injury. Our study is of great significance in promoting the understanding of the pathogenesis and treatment of HS-induced liver injury.

Hsp70 overexpression in Drosophila hemocytes attenuates benzene-induced immune and developmental toxicity via regulating ROS/JNK signaling pathway

Benzene, a ubiquitous environmental chemical, is known to cause immune dysfunction and developmental defects. This study aims to investigate the relation between benzene-induced immune dysfunction and developmental toxicity in a genetically tractable animal model, Drosophila melanogaster. Further, the study explored the protective role of Heat Shock Protein 70 (Hsp70) against benzene-induced immunotoxicity and subsequent developmental impact. Drosophila larvae exposed to benzene (1.0, 10.0, and 100.0 mM) were examined for total hemocyte (immune cells) count, phagocytic activity, oxidative stress, apoptosis, and their developmental delay and reduction were analyzed. Benzene exposure for 48 h reduced the total hemocytes count and phagocytic activity, along with an increase in the Reactive Oxygen Species (ROS), and lipid peroxidation in the larval hemocytes. Subsequently, JNK-dependent activation of the apoptosis (Caspase-3 dependent) was also observed. During their development, benzene exposure to Drosophila larvae led to 3 days of delay in development, and ~40% reduced adult emergence. Hsp70-overexpression in hemocytes was found to mitigate benzene-induced oxidative stress and abrogated the JNK-mediated apoptosis in hemocytes, thus restoring total hemocyte count and improving phagocytotic activity. Further, hsp70-overexpression in hemocytes also lessened the benzene-induced developmental delay (rescue of 2.5 days) and improved adult emergence (~20%) emergence, revealing a possible control of immune cells on the organism's development and survival. Overall, this study established that hsp70-overexpression in the Drosophila hemocytes confers protection against benzene-induced immune injury via regulating the ROS/JNK signaling pathway, which helps in the organism's survival and development.

Glycol-Chitosan-Based Technetium-99m-Loaded Multifunctional Nanomicelles: Synthesis, Evaluation, and In Vivo Biodistribution

We hereby propose the use of stable, biocompatible, and uniformly sized polymeric micelles as high-radiotracer-payload carriers at region-of-interest with negligible background activity due to no or low offsite radiolysis. We modified glycol chitosan (GC) polymer with varying levels of palmitoylation (P) and quaternization (Q). Quaternary ammonium palmitoyl glycol chitosan (GCPQ) with a Q:P ratio of 9:35 (Q9P35GC) offers >99% biocompatibility at 10 mg mL−1. Q9P35GC micelles exhibit >99% 99mTechnetium (99mTc) radiolabeling via the stannous chloride reduction method without heat. The 99mTc-Q9P35GC micelles (65 ± 3 nm) exhibit >98% 6 h serum stability at 37 °C and 7 day of radiochemical stability at 25 °C. HepG2 cells show a higher uptake of FITC-Q9P35GC than Q13P15GC and Q20P15GC. The in vivo 24 h organ cumulated activity (MBq h) order follows: liver (234.4) > kidneys (60.95) > GIT (0.73) > spleen (88.84). The liver to organ ratio remains higher than 2.4, rendering a better contrast in the liver. The radiotracer uptake decreases significantly in fibrotic vs. normal liver, whereas a blocking study with excess Q9P35GC significantly decreases the radiotracer uptake in a healthy vs. fibrotic liver. FITC-Q9P35GC shows in vivo hepato-specific uptake. Radiotracer liver uptake profile follows reversible binding kinetics with data fitting to two-tissue compartmental (2T), and graphical Ichise multilinear analysis (MA2) with lower AIC and higher R2 values, respectively. The study concludes that 99mTc-Q9P35GC can be a robust radiotracer for noninvasive hepatocyte function assessment and diagnosis of liver fibrosis. Furthermore, its multifunctional properties enable it to be a promising platform for nanotheranostic applications.

Enhanced intestinal permeability and intestinal co-morbidities in heat strain: A review and case for autodigestion

Enhanced intestinal permeability is a pervasive issue in modern medicine, with implications demonstrably associated with significant health consequences such as sepsis, multiorgan failure, and death. Key issues involve the trigger mechanisms that could compromise intestinal integrity and increase local permeability allowing the passage of larger, potentially dangerous molecules. Heat stress, whether exertional or environmental, may modulate intestinal permeability and begs interesting questions in the context of global climate change, increasing population vulnerabilities, and public health. Emerging evidence indicates that intestinal leakage of digestive enzymes and associated cell dysfunctions--a process referred to as autodigestion--may play a critical role in systemic physiological damage within the body. This increased permeability is exacerbated in the presence of elevated core temperatures. We employed Latent Dirichlet Allocation (LDA) topic modeling methods to analyze the relationship between heat stress and the nascent theory of autodigestion in a systematic, quantifiable, and unbiased manner. From a corpus of 11,233 scientific articles across four relevant scientific journals (Gut, Shock, Temperature, Gastroenterology), it was found that over 1,000 documents expressed a relationship between intestine, enhanced permeability, core temperature, and heat stress. The association has grown stronger in recent years, as heat stress and potential autodigestion are investigated in tandem, yet still by a limited number of specific research studies. Such findings justify the design of future studies to critically test novel interventions against digestive enzymes permeating the intestinal tract, especially the small intestine.

Silencing of the MEKK2/MEKK3 Pathway Protects against Spinal Cord Injury via the Hedgehog Pathway and the JNK Pathway

Spinal cord injury (SCI) is a devastating medical condition, often accompanied by motor and sensory dysfunction. The Hedgehog (Hh) pathway has a protective role in pathological injury after SCI. However, the specific mechanism remains unclear. The present study aimed to confirm the effects of the mitogen-activated protein kinase kinase-2 (MEKK2)/MEKK3/JNK/Hh pathway on SCI. SCI rat models were established and then inoculated with plasmids overexpressing MEKK2/MEKK3 or with small interfering RNA (siRNA) against MEKK2/MEKK3. The expression of MEKK2 and -3 was detected in dorsal root ganglia (DRG) cells. The motor function of hindlimbs, the expression of the c-Jun N-terminal kinase (JNK)- and Hh-pathway-related genes, and the level of neurofilament-200 (NF-200) and glial fibrillary acidic protein (GFAP) were measured. MEKK2 and -3 were expressed at a high level in DRG cells. The silencing of MEKK2/MEKK3 in rats caused an increase in the expression of glioma-associated oncogene homolog-1 (Gli-1), Nestin, smoothened (Smo), and Sonic Hedgehog (Shh). The Basso, Beattie, and Bresnahan (BBB) rating and the level of NF-200 protein also increased. However, the expression of monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1β (MIP-1β), MIP-3α, p-JNK/JNK, and p-c-Jun/c-Jun and the level of GFAP were reduced. Downregulation of MEKK2/MEKK3 ameliorated the symptoms of SCI by promoting neural progenitor cell differentiation via activating the Hh pathway and disrupting the JNK pathway. The findings in this study reveal a potential biomarker for SCI treatment.

Antifibrotic effects of Fraxetin on carbon tetrachloride-induced liver fibrosis by targeting NF-κB/IκBα, MAPKs and Bcl-2/Bax pathways

BACKGROUND

Liver fibrosis is a chronic lesion which ultimately results in cirrhosis and possible death. Although the high incidence and lethality, few therapies are effective for liver fibrosis. Fraxetin (7,8-dihydroxy-6-methoxy coumarin), a natural product extracted from cortex fraxini, has exhibited a significant hepatoprotective and anti-fibrotic properties. However, the underlying mechanism of the anti-hepatic fibrotic property remains unknown.

METHODS

48 Male Sprague Dawley rats were divided into four groups at random which were named as normal group, model group, fraxetin 25 mg/kg and 50 mg/kg group. The experimental model of liver fibrosis was founded by carbon tetrachloride (CCl₄) rats which were simultaneously treated with fraxetin (25 mg/kg or 50 mg/kg). Normal groups received equal volumes of saline and peanut oil.

RESULTS

Results showed that fraxetin ameliorated CCl₄ induced liver damage and fibrosis. Furthermore, histopathology examinations revealed that fraxetin improved the morphology and alleviated collagen deposition in fibrotic liver. Fraxetin inhibited inflammation and hepatocytes apoptosis by modulating the NF-κB/IκBα, MAPKs and Bcl-2/Bax signaling pathways.

CONCLUSION

Our findings indicate that fraxetin is effective in preventing liver fibrosis through inhibiting inflammation and hepatocytes apoptosis which is associated with regulating NF-κB/IκBα, MAPKs and Bcl-2/Bax signaling pathways in rats.

MIP-1α induces inflammatory responses by upregulating chemokine receptor 1/chemokine receptor 5 and activating c-Jun N-terminal kinase and mitogen-activated protein kinase signaling pathways in acute pancreatitis

OBJECTIVE

We aimed to investigate the association of macrophage inflammatory protein (MIP)-1α (CCL3) expression with the severity of acute pancreatitis (AP).

METHODS

The patients with AP were selected and divided into mild AP (MAP), moderately severe AP (MSAP), and severe AP (SAP) groups according to the severity of AP. The pancreatic acinar cell line Ar42 j was treated with cerulein to induce in vitro cell AP model. The expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and the activation of the c-Jun N-terminal kinase (JNK)/p38 mitogen-activated protein kinase (MAPK) signaling pathway in stimulated or transfected Ar42 j cells were detected.

RESULTS

We detected that the upregulation of MIP-1α was associated with the severity of AP. Patients with SAP showed the highest MIP-1α contents, followed by MSAP, and, lastly, MAP. In cerulein-stimulated Ar42 j cells, the upregulation of MIP-1α, CCR5, TNF-α, and IL-6 was time dependent. In addition, in human recombinant MIP-1α treated Ar42 j cells, the upregulation of TNF-α and IL-6 was MIP-1α-dose-dependent. In contrast, we detected the inhibition of TNF-α and IL-6 in MIP-1α small interfering RNA (siRNA)-treated cells. Also, the activation of the JNK/p38 MAPK signaling pathway was induced and inhibited by human recombinant MIP-1α and MIP-1α siRNA, respectively.

CONCLUSION

These results suggested that MIP-1α might be used as a biomarker for the prognosis of AP severity. The MIP-1α-induced inflammatory responses in AP were mediated by TNF-α and IL-6, which were associated with the activation of the JNK/p38 MAPK signaling pathway.