Human Amnion Epithelial Cells and Their Derived Exosomes Alleviate Sepsis-Associated Acute Kidney Injury via Mitigating Endothelial Dysfunction

Exosome-based therapies for inflammatory disorders: a review of recent advances

Exosomes, small extracellular vesicles secreted by cells, have emerged as focal mediators in intercellular communication and therapeutic interventions across diverse biomedical fields. Inflammatory disorders, including inflammatory bowel disease, acute liver injury, lung injury, neuroinflammation, and myocardial infarction, are complex conditions that require innovative therapeutic approaches. This review summarizes recent advances in exosome-based therapies for inflammatory disorders, highlighting their potential as diagnostic biomarkers and therapeutic agents. Exosomes have shown promise in reducing inflammation, promoting tissue repair, and improving functional outcomes in preclinical models of inflammatory disorders. However, further research is needed to overcome the challenges associated with exosome isolation, characterization, and delivery, as well as to fully understand their mechanisms of action. Current limitations and future directions in exosome research underscore the need for enhanced isolation techniques and deeper mechanistic insights to harness exosomes' full therapeutic potential in clinical applications. Despite these challenges, exosome-based therapies hold great potential for the treatment of inflammatory disorders and may offer a new paradigm for personalized medication.

Human Umbilical Cord-Derived Mesenchymal Stem Cells-Exosomes-Delivered miR-375 Targets HDAC4 to Promote Autophagy and Suppress T Cell Apoptosis in Sepsis-Associated Acute Kidney Injury

This study sought to elucidate the mechanism of human umbilical cord-derived mesenchymal stem cells (HUCMSCs)-exosomes (Exos) in sepsis-associated acute kidney injury (SAKI). Exos were isolated from HUCMSCs and co-cultured with CD4+ T cells exposed to lipopolysaccharide to detect the effects of HUCMSCs-Exos on CD4+ T cell apoptosis and autophagy. miR-375 expression in CD4+ T cells and HUCMSCs-Exos was examined. The relationship between miR-375 and HDAC4 was analyzed. A mouse model of SAKI was established and injected with HUCMSCs-Exos to verify the function of HUCMSCs-Exos in vivo. HUCMSCs-Exos inhibited lipopolysaccharide-induced apoptosis of CD4+ T cells and promoted autophagy. miR-375 expression was noted to be elevated in the HUCMSCs-Exos. Importantly, HUCMSCs-Exos could deliver miR-375 into CD4+ T cells where miR-375 targeted HDAC4 and negatively regulated its expression. By this mechanism, HUCMSCs-Exos decreased CD4+ T cell apoptosis and augmented autophagy. This finding was further confirmed in an in vivo SAKI model. Collectively, HUCMSCs-Exos can protect against SAKI via delivering miR-375 that promotes autophagy and arrests T cell apoptosis through HDAC4 downregulation. These findings suggest a promising therapeutic potential for HUCMSCs-Exos in the context of SAKI.

The Therapeutic Potential of Exosome Therapy in Sepsis Management: Addressing Complications and Improving Outcomes"

Infection occurs when pathogens penetrate tissues, reproduce, and trigger a host response to both the infectious agents and their toxins. A diverse array of pathogens, including viruses and bacteria, can cause infections. The host's immune system employs several mechanisms to combat these infections, typically involving an innate inflammatory response. Inflammation is a complex biological reaction that can affect various parts of the body and is a key component of the response to harmful stimuli. Sepsis arises when the body's response to infection leads to widespread damage to tissues and organs, potentially resulting in severe outcomes or death. The initial phase of sepsis involves immune system suppression. Early identification and targeted management are crucial for improving sepsis outcomes. Common treatment approaches include antibiotics, intravenous fluids, blood cultures, and monitoring urine output. This study explores the potential of exosome therapy in enhancing the management and alleviation of sepsis symptoms.

Neoastilbin ameliorates sepsis-induced liver and kidney injury by blocking the TLR4/NF-κB pathway

Sepsis frequently causes systemic inflammatory response syndrome and multiple organ failure in patients. Neoastilbin (NAS) is a flavonoid that plays vital functions in inflammation. This work aims to investigate the protective effects of NAS against sepsis-induced liver and kidney injury and elucidate its underlying mechanisms. The mouse model was established using cecal ligation puncture (CLP) induction. NAS was given to mice by gavage for 7 consecutive days before surgery. Liver and kidney function, oxidative stress, and inflammatory factors in serum or tissues were examined by ELISA or related kits. The expression of relevant proteins was assessed by Western blot. Hematoxylin and eosin and/or periodic acid-Schiff staining revealed that NAS ameliorated the pathological damage in liver and kidney tissues of CLP-induced mice. NAS improved liver and kidney functions, as evidenced by elevated levels of blood urea nitrogen, Creatinine, ALT, and AST in the serum of septic mice. TUNEL assay and the expression of Bcl-2 and Bax showed that NAS dramatically reduced apoptosis in liver and renal tissues. NAS treatment lowered the levels of myeloperoxidase and malondialdehyde, while elevated the superoxide dismutase content in liver and kidney tissues of CLP-induced mice. The levels of inflammatory cytokines (IL-6, TNF-α, and IL-1β) in the serum and both tissues of CLP-injured mice were markedly decreased by NAS. Mechanically, NAS downregulated TLR4 expression and inhibited NF-κB activation, and overexpression of TLR4 reversed the protective effects of NAS against liver and kidney injury. Collectively, NAS attenuated CLP-induced apoptosis, oxidative stress, inflammation, and dysfunction in the liver and kidney by restraining the TLR4/NF-κB pathway.

Pretreatment with Inflammatory Factors Altered the Secretome of Human Amniotic Epithelial Cells

Human amniotic epithelial cells (hAECs) are novel and promising therapeutic agents for patients suffering from degenerative diseases. Studies have demonstrated that the therapeutic effects of hAECs mainly depend on their paracrine components. Currently, appropriate pretreatment is a widely confirmed strategy for enhancing the repair potential of stem cells; however, the effect of proinflammatory factor pretreatment on hAECs and their secretome is still unclear. In this study, we used the well-characterized proinflammatory factors tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) to stimulate hAECs and analyzed the effect of TNF-α and IFN-γ on hAECs, including gene expression profile, paracrine proteins, and microRNAs (miRNAs) in exosomes. Results showed that TNF-α and IFN-γ pretreatment improved the viability of hAECs but inhibited the proliferation of hAECs. TNF-α and IFN-γ pretreatment altered the gene expression profile of hAECs, and upregulated differentially expressed genes were predominantly enriched in biological adhesion, antioxidant activity, and response to IFN-beta. In addition, TNF-α and IFN-γ pretreatment enhanced the paracrine secretion of cytokines by hAECs. The upregulated differentially expressed proteins were mainly enriched in tissue remodeling proteins and cytokine-cytokine receptor. Notably, the expression of miRNAs in exosomes from hAECs was also changed by TNF-α and IFN-γ pretreatment. The target genes of upregulated exosomal miRNAs substantially contributed to the response to stimulus, metabolic pathways, and PI3K-Akt signaling pathway. Our findings improve our understanding of the biological characteristics of hAECs after proinflammatory factor pretreatment and provide novel insights to strengthen and optimize the therapeutic potential of hAECs and their secretome in regenerative medicine.

Proteomics of urinary small extracellular vesicles in early diagnosis of kidney diseases in children-expectations and limitations

The primary function of the kidneys is to maintain systemic homeostasis (disruption of renal structure and function results in multilevel impairment of body function). Kidney diseases are characterized by a chronic, progressive course and may result in the development of chronic kidney disease (CKD). Evaluation of the composition of the proteome of urinary small extracellular vesicles (sEVs) as a so-called liquid biopsy is a promising new research direction. Knowing the composition of sEV could allow localization of cellular changes in specific sections of the nephron or the interstitial tissue before fixed changes, detectable only at an advanced stage of the disease, occur. Research is currently underway on the role of sEVs in the diagnosis and monitoring of many disease entities. Reports in the literature on the subject include: diabetic nephropathy, focal glomerulosclerosis in the course of glomerulopathies, renal fibrosis of various etiologies. Studies on pediatric patients are still few, involving piloting if small groups of patients without validation studies. Here, we review the literature addressing the use of sEV for diagnosis of the most common urinary disorders in children. We evaluate the clinical utility and define limitations of markers present in sEV as potential liquid biopsy.

Systems Approaches to Cell Culture-Derived Extracellular Vesicles for Acute Kidney Injury Therapy: Prospects and Challenges

Acute kidney injury (AKI) is a heterogeneous syndrome, comprising diverse etiologies of kidney insults that result in high mortality and morbidity if not well managed. Although great efforts have been made to investigate underlying pathogenic mechanisms of AKI, there are limited therapeutic strategies available. Extracellular vesicles (EV) are membrane-bound vesicles secreted by various cell types, which can serve as cell-free therapy through transfer of bioactive molecules. In this review, we first overview the AKI syndrome and EV biology, with a particular focus on the technical aspects and therapeutic application of cell culture-derived EVs. Second, we illustrate how multi-omic approaches to EV miRNA, protein, and genomic cargo analysis can yield new insights into their mechanisms of action and address unresolved questions in the field. We then summarize major experimental evidence regarding the therapeutic potential of EVs in AKI, which we subdivide into stem cell and non-stem cell-derived EVs. Finally, we highlight the challenges and opportunities related to the clinical translation of animal studies into human patients.

Exosomes Highlight Future Directions in the Treatment of Acute Kidney Injury

Acute kidney injury (AKI) is a severe health problem associated with high morbidity and mortality rates. It currently lacks specific therapeutic strategies. This review focuses on the mechanisms underlying the actions of exosomes derived from different cell sources, including red blood cells, macrophages, monocytes, mesenchymal stem cells, and renal tubular cells, in AKI. We also investigate the effects of various exosome contents (such as miRNA, lncRNA, circRNA, mRNA, and proteins) in promoting renal tubular cell regeneration and angiogenesis, regulating autophagy, suppressing inflammatory responses and oxidative stress, and preventing fibrosis to facilitate AKI repair. Moreover, we highlight the interactions between macrophages and renal tubular cells through exosomes, which contribute to the progression of AKI. Additionally, exosomes and their contents show promise as potential biomarkers for diagnosing AKI. The engineering of exosomes has improved their clinical potential by enhancing isolation and enrichment, target delivery to injured renal tissues, and incorporating small molecular modifications for clinical use. However, further research is needed to better understand the specific mechanisms underlying exosome actions, their delivery pathways to renal tubular cells, and the application of multi-omics research in studying AKI.

Nephropathy Is Aggravated by Fatty Acids in Diabetic Kidney Disease through Tubular Epithelial Cell Necroptosis and Is Alleviated by an RIPK-1 Inhibitor

Introduction

Diabetic kidney disease (DKD), one of the leading causes of end-stage renal disease, has complex pathogenic mechanisms and few effective clinical therapies. DKD progression is accompanied by the loss of renal resident cells, followed by chronic inflammation and extracellular matrix deposition. Necroptosis is a newly discovered form of regulated cell death and is a major form of intrinsic cell loss in certain diabetic complications such as cardiomyopathy, intestinal disease, and retinal neuropathy; however, its significance in DKD is largely unknown.

Methods

In this study, the expression of necroptosis marker phosphorylated MLKL (p-MLKL) in renal biopsy tissues of patients with DKD was detected using immunofluorescence and semiquantified using immunohistochemistry. The effects of different disease-causing factors on necroptosis activation in human HK-2 cells were evaluated using immunofluorescence and Western blotting. db/db diabetic mice were fed a high-fat diet to establish an animal model of DKD with significant renal tubule damage. Mice were treated with the RIPK1 inhibitor RIPA-56 to evaluate its renal protective effects. mRNA transcriptome sequencing was used to explore the changes in signaling pathways after RIPA-56 treatment. Oil red O staining and electron macroscopy were used to observe lipid droplet accumulation in renal biopsy tissues and mouse kidney tissues.

Results

Immunostaining of phosphorylated RIPK1/RIPK3/MLKL verified the occurrence of necroptosis in renal tubular epithelial cells of patients with DKD. The level of the necroptosis marker p-MLKL correlated positively with the severity of renal functional, pathological damages, and lipid droplet accumulation in patients with DKD. High glucose and fatty acids were the main factors causing necroptosis in human renal tubular HK-2 cells. Renal function deterioration and renal pathological injury were accelerated, and the necroptosis pathway was activated in db/db mice fed a high-fat diet. Application of RIPA-56 effectively reduced the degree of renal injury, inhibited the necroptosis pathway activation, and reduced necroinflammation and lipid droplet accumulation in the renal tissues of db/db mice fed a high-fat diet.

Conclusion

The present study revealed the role of necroptosis in the progression of DKD and might provide a new therapeutic target for the treatment of DKD.

Protective properties of extracellular vesicles in sepsis models: a systematic review and meta-analysis of preclinical studies

BACKGROUND

Multiple preclinical studies have reported a beneficial effect of extracellular vesicles (EVs), especially mesenchymal stem cells derived EVs (MSC-EVs), in the treatment of sepsis. However, the therapeutic effect of EVs is still not universally recognized. Therefore, we conducted this meta-analysis by summarizing data from all published studies that met certain criteria to systematically review the association between EVs treatment and mortality in animal models of sepsis.

METHODS

Systematic retrieval of all studies in PubMed, Cochrane and Web of Science that reported the effects of EVs on sepsis models up to September 2022. The primary outcome was animal mortality. After screening the eligible articles according to inclusion and exclusion criteria, the inverse variance method of fixed effect model was used to calculate the joint odds ratio (OR) and 95% confidence interval (CI). Meta-analysis was performed by RevMan version 5.4.

RESULTS

In total, 17 studies met the inclusion criteria. Meta-analysis of those studies showed that EVs treatment was associated with reduced mortality in animal models of sepsis (OR 0.17 95% CI: 0.11,0.26, P < 0.001). Further subgroup analysis showed that the mode of sepsis induction, the source, dose, time and method of injection, and the species and gender of mice had no significant effect on the therapeutic effect of EVs.

CONCLUSION

This meta-analysis showed that MSC-EVs treatment may be associated with lower mortality in animal models of sepsis. Subsequent preclinical studies will need to address the standardization of dose, source, and timing of EVs to provide comparable data. In addition, the effectiveness of EVs in treating sepsis must be studied in large animal studies to provide important clues for human clinical trials.