Bone Marrow Mesenchymal Stem Cells Combat Lipopolysaccharide-Induced Sepsis in Rats via Amendment of P38-MAPK Signaling Cascade

Machine learning reveals the rules governing the efficacy of mesenchymal stromal cells in septic preclinical models

BACKGROUND

Mesenchymal Stromal Cells (MSCs) are the preferred candidates for therapeutics as they possess multi-directional differentiation potential, exhibit potent immunomodulatory activity, are anti-inflammatory, and can function like antimicrobials. These capabilities have therefore encouraged scientists to undertake numerous preclinical as well as a few clinical trials to access the translational potential of MSCs in disease therapeutics. In spite of these efforts, the efficacy of MSCs has not been consistent-as is reflected in the large variation in the values of outcome measures like survival rates. Survival rate is a resultant of complex cascading interactions that not only depends upon upstream experimental factors like dosage, time of infusion, type of transplant, etc.; but is also dictated, post-infusion, by intrinsic host specific attributes like inflammatory microniche including proinflammatory cytokines and alarmins released by the damaged host cells. These complex interdependencies make a researcher's task of designing MSC transfusion experiments challenging.

METHODS

In order to identify the rules and associated attributes that influence the final outcome (survival rates) of MSC transfusion experiments, we decided to apply machine learning techniques on manually curated data collected from available literature. As sepsis is a multi-faceted condition that involves highly dysregulated immune response, inflammatory environment and microbial invasion, sepsis can be an efficient model to verify the therapeutic effects of MSCs. We therefore decided to implement rule-based classification models on data obtained from studies involving interventions of MSCs in sepsis preclinical models.

RESULTS

The rules from the generated graph models indicated that survival rates, post-MSC-infusion, are influenced by factors like source, dosage, time of infusion, pre-Interleukin-6 (IL-6)/ Tumour Necrosis Factor- alpha (TNF-α levels, etc. CONCLUSION: This approach provides important information for optimization of MSCs based treatment strategies that may help the researchers design their experiments.

Protective and immunomodulatory effects of mesenchymal stem cells on multiorgan injury in male rats with heatstroke

Heatstroke (HS) causes multiple organ dysfunction syndrome (MODS) with a mortality rate of 60% after hospitalization. Currently, there is no effective and targeted approach for the treatment of HS. Despite growing evidence that mesenchymal stem cells (MSCs) may reduce multiorgan damage and improve survival through immunomodulatory effects in several diseases, no one has tested whether MSCs have immunomodulatory effects in heatstroke. The present study focused on pathological changes and levels of the cytokines and immunoglobulins to investigate the mechanisms underlying the protective effect and the anti-inflammatory effects of MSCs. We found that MSCs treatment significantly reduced the 28-day mortality rate (P < 0.05), the levels of hepatic and renal function markers on day 1 (P < 0.01) and the pathological lesion scores of multiple organs in HS rats. The levels of IgG1, IgM, and IgA of the HS + MSC group was significantly higher than that in HS group on days 3 and 28(P < 0.05). In conclusion, MSCs contribute to protecting against multiorgan injury, reducing pro-inflammatory cytokines, stabilizing immunoglobulins, and reducing the mortality rate of HS rats.

TREATMENT WITH HUMAN UMBILICAL CORD-DERIVED MESENCHYMAL STEM CELLS IN A PIG MODEL OF SEPSIS-INDUCED ACUTE KIDNEY INJURY: EFFECTS ON MICROVASCULAR ENDOTHELIAL CELLS AND TUBULAR CELLS IN THE KIDNEY

ABSTRACT

Background: Approximately 50% of patients with sepsis develop acute kidney injury (AKI), which is predictive of poor outcomes, with mortality rates of up to 70%. The endothelium is a major target for treatments aimed at preventing the complications of sepsis. We hypothesized that human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) could attenuate tubular and endothelial injury in a porcine model of sepsis-induced AKI. Methods: Anesthetized pigs were induced to fecal peritonitis, resulting in septic shock, and were randomized to treatment with fluids, vasopressors, and antibiotics (sepsis group; n = 11) or to that same treatment plus infusion of 1 × 10 6 cells/kg of hUC-MSCs (sepsis+MSC group; n = 11). Results: At 24 h after sepsis induction, changes in serum creatinine and mean arterial pressure were comparable between the two groups, as was mortality. However, the sepsis+MSC group showed some significant differences in comparison with the sepsis group: lower fractional excretions of sodium and potassium; greater epithelial sodium channel protein expression; and lower protein expression of the Na-K-2Cl cotransporter and aquaporin 2 in the renal medulla. Expression of P-selectin, thrombomodulin, and vascular endothelial growth factor was significantly lower in the sepsis+MSC group than in the sepsis group, whereas that of Toll-like receptor 4 (TLR4) and nuclear factor-kappa B (NF-κB) was lower in the former. Conclusion: Treatment with hUC-MSCs seems to protect endothelial and tubular cells in sepsis-induced AKI, possibly via the TLR4/NF-κB signaling pathway. Therefore, it might be an effective treatment for sepsis-induced AKI.

L-Theanine alleviates heat stress-induced impairment of immune function by regulating the p38 MAPK signalling pathway in mice

With the current trend of global warming, heat stress-induced impairment could seriously endanger human health. L-Theanine is a non-protein amino acid in tea with various biological activities, including immunoregulatory, anti-anxiety, and anti-oxidation. However, its effect on immune function under heat stress and the underlying mechanism are currently unclear. In this study, male BALB/c mice were used as experimental objects to explore the effect of L-theanine on heat stress-induced changes in immune function and its mechanism. Three doses of L-theanine were used: low (100 mg kg^-1 d^-1), medium (200 mg kg^-1 d^-1), and high (400 mg kg^-1 d^-1). Treatment with L-theanine could attenuate the heat stress-induced reductions in body weight and feed intake in mice, alleviate damage in the liver and jejunum, and inhibit the inflammatory factors IL-6, IL-1β, and TNF-α. Aspartate aminotransferase and alanine transaminase activity levels and the malondialdehyde content decreased, while the IgA, IgM, and IgG contents increased in response to L-theanine. It is possible that L-theanine affects the P38 signalling pathway and inhibits the increase in p-P65/P65 caused by the overexpression of HSP27 and regulation of PPAR-γ and Foxp3 proteins, thereby alleviating immune dysfunction caused by heat stress.

Mesenchymal stem cell-based therapy as a new therapeutic approach for acute inflammation

Acute inflammatory diseases such as acute colitis, kidney injury, liver failure, lung injury, myocardial infarction, pancreatitis, septic shock, and spinal cord injury are significant causes of death worldwide. Despite advances in the understanding of its pathophysiology, there are many restrictions in the treatment of these diseases, and new therapeutic approaches are required. Mesenchymal stem cell-based therapy due to immunomodulatory and regenerative properties is a promising candidate for acute inflammatory disease management. Based on preclinical results, mesenchymal stem cells and their-derived secretome improved immunological and clinical parameters. Furthermore, many clinical trials of acute kidney, liver, lung, myocardial, and spinal cord injury have yielded promising results. In this review, we try to provide a comprehensive view of mesenchymal stem cell-based therapy in acute inflammatory diseases as a new treatment approach.

CYTL1 Promotes the Activation of Neutrophils in a Sepsis Model

As a novel cytokine, cytokine-like 1 (CYTL1) is a classical secretory protein, and its potential biological function remains to be determined. In this study, we found that expression of CYTL1 was upregulated in neutrophils upon inflammatory stimuli. We demonstrated that CYTL1 enhanced phagocytosis of Escherichia coli by activated neutrophils both in vivo and in vitro through phosphorylation of protein kinase B (Akt). CYTL1-induced chemotactic activity in lipopolysaccharide (LPS) stimulated neutrophils, and the mechanism may be related to CC chemokine receptor 2 (CCR2) mediated action. CYTL1 also increased the release of reactive oxygen species (ROS) in LPS-stimulated neutrophils. These data indicate that upon inflammatory stimulation, neutrophil-derived CYTL1 may play a crucial role in the activation of neutrophils during pathogenic infections.

Enhanced Effect of IL-1β-Activated Adipose-Derived MSCs (ADMSCs) on Repair of Intestinal Ischemia-Reperfusion Injury via COX-2-PGE2 Signaling

Adipose-derived mesenchymal stem cells (ADMSCs) have been used for treating tissue injury, and preactivation enhances their therapeutic effect. This study is aimed at investigating the therapeutic effect of activated ADMSCs by IL-1β on the intestinal ischaemia-reperfusion (IR) injury and exploring potential mechanisms. ADMSCs were pretreated with IL-1β in vitro, and activation of ADMSCs was assessed by α-SMA and COX-2 expressions and secretary function. Activated ADMSCs was transplanted into IR-injured intestine in a mouse model, and therapeutic effect was evaluated. In addition, to explore underlying mechanisms, COX-2 expression was silenced to investigate its role in activated ADMSCs for treatment of intestinal IR injury. When ADMSCs were pretreated with 50 ng/ml IL-1β for 24 hr, expressions of α-SMA and COX-2 were significantly upregulated, and secretions of PGE₂, SDF-1, and VEGF were increased. When COX-2 was silenced, the effect of IL-1β treatment was abolished. Activated ADMSCs with IL-1β significantly suppressed inflammation and apoptosis and enhanced healing of intestinal IR injury in mice, and these effects were impaired by COX-2 silencing. The results of RNA sequencing suggested that compared with the IR injury group activated ADMSCs induced alterations in mRNA expression and suppressed the activation of the NF-κB-P65, MAPK-ERK1/2, and PI3K-AKT pathways induced by intestinal IR injury, whereas silencing COX-2 impaired the suppressive effect of activated ADMSCs on these pathway activations induced by IR injury. These data suggested that IL-1β pretreatment enhanced the therapeutic effect of ADMSCs on intestinal IR injury repairing via activating ADMSC COX-2-PGE₂ signaling axis and via suppressing the NF-κB-P65, MAPK-ERK1/2, and PI3K-AKT pathways in the intestinal IR-injured tissue.

Propofol post-conditioning lessens renal ischemia/reperfusion-induced acute lung injury associated with autophagy and apoptosis through MAPK signals in rats

Renal Ischemia/Reperfusion (rI/R)-induced acute lung injury (ALI) is a major problem in rI/R. The objective of the current study was to explore the defensive roles of propofol (Pro), an intravenous anesthetic, on rI/R-induced ALI through mitogen-activated protein kinase (MAPK) signaling. Rats were divided into Sham, Pro (10 mg/kg), rI/R, rI/R + Pro (5 mg/kg), and rI/R + Pro (10 mg/kg) groups. Rats were treated with Pro at 1 h after rI/R treatment. Serum and lung tissues at 24 h after rI/R were collected to evaluate morphological changes and the expression of myeloperoxidase (MPO), inflammatory cytokines, and crucial proteins in the MAPK pathway. Pro attenuated the production of mediators, resulting in reduced levels of autophagy and apoptosis by restricting the MAPK pathway in rI/R-induced ALI model. Pro represses rI/R-induced pulmonary autophagy and apoptosis by decreasing the production of inflammatory molecules, and the effects of Pro are involved in the inhibition of the MAPK pathway.

Agomelatine could prevent brain and cerebellum injury against LPS-induced neuroinflammation in rats

Sepsis, systemic hyper-inflammatory immune response, causes the increase of morbidity and mortality rates due to multi-organ diseases such as neurotoxicity. Lipopolysaccharide (LPS) induces inflammation, oxidative stress and apoptosis to cause brain damage. We aimed to evaluate the antioxidant, anti-inflammatory and antiapoptotic effects of Agomelatine (AGM) on LPS induced brain damage via NF-kB signaling. Twenty-four animals were divided into three groups as control, LPS (5 mg/kg) and LPS + AGM (20 mg/kg). Six hours after the all administrations, rats were sacrificed, brain tissues were collected for biochemical, histopathological and immunohistochemical analysis. In LPS group; total oxidant status (TOS), OSI index, Caspase-8 (Cas-8), NF-kß levels increased and Total antioxidant status (TAS) levels decreased biochemically and Cas-8, haptoglobin and IL-10 expressions increased and sirtuin-1 (SIRT-1) levels decreased immunohistochemically. AGM treatment reversed these parameters except haptoglobin levels in hippocampus and SIRT-1 levels in cerebellum. Besides, AGM treatment blocked the phosphorylation of NF-kB biochemically and ameliorated increased the levels of hyperemia, edema and degenerative changes histopathologically. In conclusion, AGM enhanced SIRT-1 levels to negatively regulate the transcription and activation of p-NF-kB/p65 which caused to ameliorate inflammation, oxidative stress and apoptosis.

Mesenchymal stem cell treatment attenuates liver and lung inflammation after ethanol intoxication and burn injury

Cutaneous burn injury is one of the most devastating injuries one can obtain, with tissue damage extending beyond the skin wound to distal organs, including the gastrointestinal tract, liver, and lungs. Multiple organ failure is a leading cause of death after burn injury, resulting in excessive systemic and localized inflammation directly contributing to end organ damage. We postulated that the gut-liver-lung inflammatory axis underscores multiple organ failure in the context of burn injury and is hyper-activated when ethanol intoxication precedes burn. Mesenchymal stem cells (MSCs) are regenerative and anti-inflammatory, and MSC treatment has been shown to be beneficial in several immune disorders and injury models. Our objective was to determine whether intravenous infusion of exogenous bone marrow-derived MSCs could reduce post-burn and intoxication pulmonary, hepatic, and systemic inflammation. Vehicle- or ethanol- (1.6 g/kg) treated mice were subjected to sham or 15% total body surface area scald burn. One hour post-injury, mice were given 5 × 10⁵ CFSE-labeled MSCs or phosphate-buffered saline intravenously (i.v.) and were euthanized 24 h later. We assessed circulating biomarkers of inflammation and liver damage, measured cytokine and chemokine production, and quantified apoptosis in lung and liver tissue. Compared to intoxicated and burned mice, those treated with MSCs had less cellularity, limited apoptosis, and a slight reduction in the pro-inflammatory cytokine interleukin-6 (IL-6) and the neutrophil chemokine, KC (CXCL1) in lung tissue. Mice with MSCs treatment had more dramatic anti-inflammatory effects on systemic and hepatic inflammation, as serum IL-6 levels were diminished by 43%, and il6 and kc expression in liver tissue were markedly reduced, as were biomarkers of liver damage, aspartate transaminase (AST) and alanine transaminase (AST), compared with intoxicated and burned mice. Taken together, our results suggest intravenous MSCs treatment can diminish systemic inflammation, lessen hepatic damage, and decrease liver and lung apoptosis and inflammation, indicating MSCs as a novel therapy for restoring homeostasis of multiple organ systems in intoxicated burn patients.

Linkage of lncRNA CRNDE sponging miR-181a-5p with aggravated inflammation underlying sepsis

This investigation was performed to verify whether lncRNA CRNDE sponging miR-181a-5p was involved with sepsis-relevant inflammatory dysfunctions. Aggregately 136 sepsis patients and 151 healthy people were recruited, and their fasting peripheral blood was gathered to detect expressions of CRNDE and miR-181a-5p. In addition, THP-1 cells were transfected with si-CRNDE, miR-181a-5p mimic, pcDNA3.1-TLR4 and si-TLR4, and then sepsis-specific inflammatory cytokines within the cells were quantified. The sponging relationships between CRNDE and miR-181a-5p, as well as between miR-181a-5p and TLR4, were ascertained by means of luciferase reporter gene assay. The experimental results revealed that over-expressed CRNDE and under-expressed miR-181a-5p were associated with shortened lifespan of sepsis patients. Mechanically, si-CRNDE-1 and miR-181a-5p mimic were able to reverse the promoting effects of LPS on production of NF-kB, TNF-α, IL-1β and IL-6 by THP-1 cells. Moreover, the expressional change of miR-181a-5p in THP-1 cells was in part owing to its being sponged by CRNDE. Lastly, TLR4, subjected to targeted modification of miR-181a-5p, was capable of disturbing the contribution of CRNDE and miR-181a-5p to THP-1 cells’ release of NF-kB, TNF-α, IL-1β and IL-6. Collectively, the CRNDE/miR-181a-5p/TLR4 axis seemed to have potential in modifying sepsis-related inflammatory pathogenesis, which offered a direction for sepsis diagnosis and treatment.