Reversing Acute Kidney Injury Using Pulsed Focused Ultrasound and MSC Therapy: A Role for HSP-Mediated PI3K/AKT Signaling

Time-course analysis of cisplatin induced AKI in preclinical models: implications for testing different sources of MSCs

BACKGROUND

Kidneys are at risk from drug-induced toxicity, with a significant proportion of acute kidney injury (AKI) linked to medications, particularly cisplatin. Existing cytoprotective drugs for cisplatin-AKI carry side effects, prompting a search for better biological therapies. Mesenchymal Stem Cells (MSCs) are under consideration given their regenerative properties, yet their clinical application has not achieved their full potential, mainly due to variability in the source of MSC tested. In addition, translating treatments from rodent models to humans remains challenging due to a lack of standardized dosing and understanding potential differential responses to cisplatin between animal strains.

METHOD

In the current study, we performed a time-course analysis of the effect of cisplatin across different mouse strains and evaluated gender related differences to create a robust preclinical model that could then be used to explore the therapeutic efficacy of different sources of MSCs for their ability to reverse AKI.

RESULT

Our data indicated that different mouse strains produce differential responses to the same cisplatin dosing regimen. Despite this, we did not observe any gender-related bias towards cisplatin nephrotoxicity. Furthermore, our time-course analysis identified that cisplatin-induced inflammation was driven by a strong CXCL1 response, which was used as a putative biomarker to evaluate the comparative therapeutic efficacy of different MSC sources in reversing AKI. Our data indicates that UC-MSCs have a stronger anti-inflammatory effect compared to BM-MSCs and AD-MSCs, which helped to ameliorate cisplatin-AKI.

CONCLUSION

Overall, our data underscores the importance of using an optimized preclinical model of cisplatin-AKI to test different therapies. We identified CXCL1 as a potential biomarker of cisplatin-AKI and identified the superior efficacy of UC-MSCs in mitigating cisplatin-AKI.

Mesenchymal Stem Cell-Derived Exosomes in Various Chronic Liver Diseases: Hype or Hope?

Chronic liver conditions are associated with high mortality rates and have a large adverse effect on human well-being as well as a significant financial burden. Currently, the only effective treatment available for the effects of liver failure and cirrhosis resulting from the progression of several chronic liver diseases is liver transplantation carried out at the original location. This implies that developing novel and effective treatments is imperative. Regenerative medicine has long been associated with stem cell therapy. Mesenchymal stem cells (MSCs), a type of cell with great differentiation potential, have become the preferred source for stem cell therapy. According to recent studies, MSCs' paracrine products-rather than their capacity for differentiation-play a significant therapeutic effect. MSC exosomes, a type of extracellular vesicle (MSC-EV), came into view as the paracrine substances of MSCs. According to research, MSC exosomes can maintain tissue homeostasis, which is necessary for healthy tissue function. All tissues contain them, and they take part in a variety of biological activities that support cellular activity and tissue regeneration in order to preserve tissue homeostasis. The outcomes support the use of MSCs and the exosomes they produce as a therapeutic option for a range of diseases. This review provides a brief overview of the source of MSC-EVs and outlines their physiological roles and biochemical capabilities. The elucidation of the role of MSC-EVs in the recovery and repair of hepatic tissues, as well as their contribution to maintaining tissue homeostasis, is discussed in relation to different chronic liver diseases. This review aims to provide new insights into the unique roles that MSC-EVs play in the treatment of chronic liver diseases.

OncoRTT: Predicting novel oncology-related therapeutic targets using BERT embeddings and omics features

Late-stage drug development failures are usually a consequence of ineffective targets. Thus, proper target identification is needed, which may be possible using computational approaches. The reason being, effective targets have disease-relevant biological functions, and omics data unveil the proteins involved in these functions. Also, properties that favor the existence of binding between drug and target are deducible from the protein’s amino acid sequence. In this work, we developed OncoRTT, a deep learning (DL)-based method for predicting novel therapeutic targets. OncoRTT is designed to reduce suboptimal target selection by identifying novel targets based on features of known effective targets using DL approaches. First, we created the “OncologyTT” datasets, which include genes/proteins associated with ten prevalent cancer types. Then, we generated three sets of features for all genes: omics features, the proteins’ amino-acid sequence BERT embeddings, and the integrated features to train and test the DL classifiers separately. The models achieved high prediction performances in terms of area under the curve (AUC), i.e., AUC greater than 0.88 for all cancer types, with a maximum of 0.95 for leukemia. Also, OncoRTT outperformed the state-of-the-art method using their data in five out of seven cancer types commonly assessed by both methods. Furthermore, OncoRTT predicts novel therapeutic targets using new test data related to the seven cancer types. We further corroborated these results with other validation evidence using the Open Targets Platform and a case study focused on the top-10 predicted therapeutic targets for lung cancer.

Integrative analysis of renal microRNA and mRNA to identify hub genes and pivotal pathways associated with cyclosporine-induced acute kidney injury in mice

Cyclosporine (CsA) is an immunosuppressive agent that often causes acute kidney injury (AKI) in children. The specific mechanisms underlying CsA-induced AKI are currently unknown. This study used an integrated network analysis of microRNA (miRNA) and mRNA expression profiles, biochemical and pathological analyses to further investigate these potential mechanisms of CsA-induced AKI. Small RNA sequence analysis identified 25 differentially expressed miRNAs, RNA sequencing analysis identified 4,109 differentially expressed mRNAs. We obtained a total of 4,367 target genes from the 25 differentially expressed miRNAs based on three algorithms, including the Mirdb, Mirtarbase, and TargetScan. 971 target genes overlapped between the 4,367 target genes and 4,109 differentially expressed mRNAs were identified for further bioinformatics analysis. Finally, 30 hub genes and two main modules were recognized. Functional enrichment analysis of 30 hub genes indicated that inflammation and epithelial-mesenchymal transition (EMT) related genes were mainly concentrated together. Pathway analysis revealed that the PI3K-Akt signaling pathway plays an integral role in CsA-induced AKI. Network analysis identified 3 important miRNAs, mmu-miR-17b-5p, mmu-miR-19b-3p, and mmu-mir-423-5p that may further promote the development of inflammatory responses and EMT by mediating a complex network of factors. Our research provides a clearer understanding the molecular mechanism of this specific drug-induced AKI by CsA use, which is useful for discovering potential targets for gene therapies, and drug development in CsA-induced AKI.

Bone Marrow Mesenchymal Stem Cells (BMSCs)-Exosomes Carrying MicroRNA-965 Attenuates Allogeneic Renal Transplant Rejection Through Regulation of Janus Kinase/Signal Transducers and Activators of Transcription 3 (JAK/STAT3)

This study intends to evaluate the potential effect of BMSC-derived exosomes (exo) on the rejection of allogeneic kidney transplantation in a rat model. BMSCs were cultured and their exos were collected for characterization, in which the expression of miR-965 was detected by PCR. Rats received orthotopic kidney transplantation and treated with exos or PBS followed by analysis of serum creatinine and BUN, inflammatory cell infiltration, renal fibrosis and vascular wall fibrosis by immunohistochemistry staining, JAK2/STAT3 phosphorylation by Western-blot, the inflammatory factor level by ELISA kit, and CD4+ cells differentiation by flow cytometry. miR-965 was enriched in BMSC-derived exo. Treatment with exo ameliorated the allograft rejection, improved renal function, and reduced the histological changes of kidney. In addition, exosomal treatment decreased the level of serum inflammatory cytokines, and altered T cell subpopulations. Meanwhile, fibrosis and neointima formation was reduced as demonstrated by related protein expression and signaling pathways was inactivated in the presence of exos. In conclusion, the miR-965 derived from BMSC-exos mitigated the renal allograft rejection through JAK/STAT3 signaling.

Mesenchymal Stem Cells-Derived Exosomes Ameliorate Ischemia/Reperfusion Induced Acute Kidney Injury in a Porcine Model

Exosomes are membrane-enclosed vesicles secreted by cells, containing a variety of biologically active ingredients including proteins, nucleic acids and lipids. In this study, we investigated the therapeutic effects of the exosomes and underlying mechanisms in a miniature pig model of ischemia/reperfusion-induced acute kidney injury (I/R-AKI). The exosomes were extracted from cultured human umbilical cord derived mesenchymal stem cells (hUC-MSCs) and infused into a miniature pig model of I/R AKI. Our results showed that 120 min of unilateral ischemia followed by reperfusion and contralateral nephrectomy resulted in renal dysfunction, severe kidney damage, apoptosis and necroptosis. Intravenous infusion of one dose of exosomes collected from about 4 × 108 hUC-MSCs significantly improved renal function and reduced apoptosis and necroptosis. Administration of hUC-MSC exosomes also reduced the expression of some pro-inflammatory cytokines/chemokines, decreased infiltration of macrophages to the injured kidneys and suppressed the phosphorylation of nuclear factor-κB and signal transducer and activator of transcription 3, two transcriptional factors related to inflammatory regulation. Moreover, hUC-MSC exosomes could promote proliferation of renal tubular cells, angiogenesis and upregulation of Klotho and Bone Morphogenetic Protein 7, two renoprotective molecules and vascular endothelial growth factor A and its receptor. Collectively, our results suggest that injection of hUC-MSC exosomes could ameliorate I/R-AKI and accelerate renal tubular cell repair and regeneration, and that hUC-MSC exosomes may be used as a potential biological therapy for Acute kidney injury patients.

Diagnostic and Therapeutic Potential of Extracellular Vesicles

Extracellular vesicles (EVs) are naturally phospholipid enclosed nanovesicles released by many cells in the body. They are stable in circulation, have low immunogenicity, and act as carriers for functionally active biological molecules. They interact with target organs and bind to the receptors. Their target specificity is important to use EVs as noninvasive diagnostic and prognostic tools. EVs play a vital role in normal physiology and cellular communication. They are known to protect their cargo from degradation, which makes them important drug carriers for targeted drug delivery. Using EVs with markers and tracking their path in systemic circulation can be revolutionary in using them as diagnostic tools. We will discuss the scope of this in this paper. Although there are limitations in EVs isolation and storage, their high biocompatibility will fuel more innovations to overcome these challenges.

Metformin Weakens the Angiogenic Potential of Human Bone Marrow Mesenchymal Stem Cells (hBMSCs) by Activating Mammalian Target of Rapamycin (mTOR) Signaling

To study metformin’s effect on the angiogenesis of human bone marrow mesenchymal stem cells (hBMSCs). Cells were treated with metformin (0.5, 1, 10, 50, 100, 200 and 500 βM) for 14 days, followed by analysis of cell viability and total fatty acid profile, level of VEGFR-2, Tie-2, VE-Cadherin and mTOR signaling protein, cell differentiation by microtubule generation and cell migration by transwell assay. Metformin dose dependently decreased cell survival and reduced palmitate, oleate, stearate and linoleate content. In addition, it downregulated VEGFR-2 and Tie-2 and decreased the angiogenic potential of BMSCs and down-regulated VE-Cadherin. Western blot and PCR analysis showed that metformin activated mTOR signaling and up-regulated the transcription of autophagyrelated genes. Metformin can reduce BMSCs angiogenic potential by regulating mTOR signal pathway.

Spatial micro-variation of 3D hydrogel stiffness regulates the biomechanical properties of hMSCs

Human mesenchymal stem cells (hMSCs) are one of the most promising candidates for cell-based therapeutic products. Nonetheless, their biomechanical phenotype afterin vitroexpansion is still unsatisfactory, for example, restricting the efficiency of microcirculation of delivered hMSCs for further cell therapies. Here, we propose a scheme using maleimide-dextran hydrogel with locally varied stiffness in microscale to modify the biomechanical properties of hMSCs in three-dimensional (3D) niches. We show that spatial micro-variation of stiffness can be controllably generated in the hydrogel with heterogeneously cross-linking via atomic force microscopy measurements. The result of 3D cell culture experiment demonstrates the hydrogels trigger the formation of multicellular spheroids, and the derived hMSCs could be rationally softened via adjustment of the stiffness variation (SV) degree. Importantly,in vitro, the hMSCs modified with the higher SV degree can pass easier through capillary-shaped micro-channels. Further, we discuss the underlying mechanics of the increased cellular elasticity by focusing on the effect of rearranged actin networks, via the proposed microscopic model of biomechanically modified cells. Overall, this work highlights the effectiveness of SV-hydrogels in reprogramming and manufacturing hMSCs with designed biomechanical properties for improved therapeutic potential.

Heat shock protein 20 promotes sirtuin 1-dependent cell proliferation in induced pluripotent stem cells

BACKGROUND

Heat shock proteins (HSPs) are molecular chaperones that protect cells against cellular stresses or injury. However, it has been increasingly recognized that they also play crucial roles in regulating fundamental cellular processes. HSP20 has been implicated in cell proliferation, but conflicting studies have shown that it can either promote or suppress proliferation. The underlying mechanisms by which HSP20 regulates cell proliferation and pluripotency remain unexplored. While the effect of HSP20 on cell proliferation has been recognized, its role in inducing pluripotency in human-induced pluripotent stem cells (iPSCs) has not been addressed.

AIM

To evaluate the efficacy of HSP20 overexpression in human iPSCs and evaluate the ability to promote cell proliferation. The purpose of this study was to investigate whether overexpression of HSP20 in iPSCs can increase pluripotency and regeneration.

METHODS

We used iPSCs, which retain their potential for cell proliferation. HSP20 overexpression effectively enhanced cell proliferation and pluripotency. Overexpression of HSP20 in iPSCs was characterized by immunocytochemistry staining and real-time polymerase chain reaction. We also used cell culture, cell counting, western blotting, and flow cytometry analyses to validate HSP20 overexpression and its mechanism.

RESULTS

This study demonstrated that overexpression of HSP20 can increase the pluripotency in iPSCs. Furthermore, by overexpressing HSP20 in iPSCs, we showed that HSP20 upregulated proliferation markers, induced pluripotent genes, and drove cell proliferation in a sirtuin 1 (SIRT1)-dependent manner. These data have practical applications in the field of stem cell-based therapies where the mass expansion of cells is needed to generate large quantities of stem cell-derived cells for transplantation purposes.

CONCLUSION

We found that the overexpression of HSP20 enhanced the proliferation of iPSCs in a SIRT1-dependent manner. Herein, we established the distinct crosstalk between HSP20 and SIRT1 in regulating cell proliferation and pluripotency. Our study provides novel insights into the mechanisms controlling cell proliferation that can potentially be exploited to improve the expansion and pluripotency of human iPSCs for cell transplantation therapies. These results suggest that iPSCs overexpressing HSP20 exert regenerative and proliferative effects and may have the potential to improve clinical outcomes.

Immunomodulatory Effects of Mesenchymal Stem Cells on Drug-Induced Acute Kidney Injury

Drug-induced nephrotoxicity is an important and increasing cause of acute kidney injury (AKI), which accounts for approximately 20% of hospitalized patients. Previous reviews studies on immunity and AKI focused mainly on ischemia-reperfusion (IR), whereas no systematic review addressing drug-induced AKI and its related immune mechanisms is available. Recent studies have provided a deeper understanding on the mechanisms of drug-induced AKI, among which acute tubular interstitial injury induced by the breakdown of innate immunity was reported to play an important role. Emerging research on mesenchymal stem cell (MSC) therapy has revealed its potential as treatment for drug-induced AKI. MSCs can inhibit kidney damage by regulating the innate immune balance, promoting kidney repair, and preventing kidney fibrosis. However, it is important to note that there are various sources of MSCs, which impacts on the immunomodulatory ability of the cells. This review aims to address the immune pathogenesis of drug-induced AKI versus that of IR-induced AKI, and to explore the immunomodulatory effects and therapeutic potential of MSCs for drug-induced AKI.

Exploring the utility of extracellular vesicles in ameliorating viral infection-associated inflammation, cytokine storm and tissue damage

Extracellular vesicles (EVs) have emerged as potential mediators of intercellular communication. EVs are nano-sized, lipid membrane-bound vesicles that contains biological information in the form of proteins, metabolites and/or nucleic acids. EVs are key regulators of tissue repair mechanisms, such as in the context of lung injuries. Recent studies suggest that EVs have the ability to repair COVID19-associated acute lung damage. EVs hold great promise for therapeutic treatments, particularly in treating a potentially fatal autoimmune response and attenuate inflammation. They are known to boost lung immunity and are involved in the pathogenesis of various lung diseases, including viral infection. EV-based immunization technology has been proven to elicit robust immune responses in many models of infectious disease, including COVID-19. The field of EV research has tremendous potential in advancing our understanding about viral infection pathogenesis, and can be translated into anti-viral therapeutic strategies.

Arbutin attenuates LPS-induced acute kidney injury by inhibiting inflammation and apoptosis via the PI3K/Akt/Nrf2 pathway

BACKGROUND

Arbutin (Ar) has anti-oxidative and anti-inflammatory activities. However, the effects of Ar on lipopolysaccharide (LPS)-induced acute kidney injury (AKI) are not clear.

PURPOSE

This study aimed to investigate the effects of Ar on LPS-induced AKI in rats.

METHODS

The possible data regarding the effects of Ar on AKI were collected by network pharmacology research. Histological changes in the kidney and the levels of blood urea nitrogen, serum creatinine, and kidney injury molecule 1 were measured to assess the effects of Ar on renal function in LPS-induced AKI. The levels of inflammatory were detected by live small-animal imaging, cytometric bead array and enzyme linked immunosorbent assay. The levels of reactive oxygen species and apoptosis of primary kidney cells were detected by flow cytometry. The oxidative stress-related markers were detected by the cuvette assay. The TLR4/NF-κB and PI3K/Akt/Nrf2 levels and apoptosis were detected by Western blot analysis. The effects of GDC-0068 (GDC, Akt inhibitor) on Ar interposed on LPS-induced NRK-52e cell apoptosis were investigated by flow cytometry.

RESULTS

The data collected by network pharmacology suggested that Ar might inhibit AKI by exerting an anti-inflammatory effect and regulating the Akt signaling pathway. The experimental results showed that Ar markedly improved renal function, and attenuated inflammation and cell apoptosis via regulating PI3K/Akt/Nrf2 pathway following LPS challenge in vivo, which blocked by GDC effectively in vitro.

CONCLUSION

In a word, this study demonstrated that Ar attenuated LPS-induced AKI by inhibiting inflammation and apoptosis via the PI3K/Akt/Nrf2 pathway.

Mesenchymal Stem Cell-Derived Extracellular Vesicles: A Potential Therapeutic Strategy for Acute Kidney Injury

Acute kidney injury (AKI) is a common and potential life-threatening disease in patients admitted to hospital, affecting 10%-15% of all hospitalizations and around 50% of patients in the intensive care unit. Severe, recurrent, and uncontrolled AKI may progress to chronic kidney disease or end-stage renal disease. AKI thus requires more efficient, specific therapies, rather than just supportive therapy. Mesenchymal stem cells (MSCs) are considered to be promising cells for cellular therapy because of their ease of harvesting, low immunogenicity, and ability to expand in vitro. Recent research indicated that the main therapeutic effects of MSCs were mediated by MSC-derived extracellular vesicles (MSC-EVs). Furthermore, compared with MSCs, MSC-EVs have lower immunogenicity, easier storage, no tumorigenesis, and the potential to be artificially modified. We reviewed the therapeutic mechanism of MSCs and MSC-EVs in AKI, and considered recent research on how to improve the efficacy of MSC-EVs in AKI. We also summarized and analyzed the potential and limitations of EVs for the treatment of AKI to provide ideas for future clinical trials and the clinical application of MSC-EVs in AKI.

Cytosolic Ca2+ transients during pulsed focused ultrasound generate reactive oxygen species and cause DNA damage in tumor cells

Mechanical forces from non-ablative pulsed focused ultrasound (pFUS) generate pro-inflammatory tumor microenvironments (TME), marked by increased cytokines, chemokines, and trophic factors, as well as immune cell infiltration and reduced tumor growth. pFUS also causes DNA damage within tumors, which is a potent activator of immunity and could contribute to changes in the TME. This study investigated mechanisms behind the mechanotransductive effects of pFUS causing DNA damage in several tumor cell types. Methods: 4T1 (murine breast tumor), B16 (murine melanoma), C6 (rat glioma), or MDA-MB-231 (human breast tumor) cells were sonicated in vitro (1.1MHz; 6MPa PNP; 10ms pulses; 10% duty cycle; 300 pulses). DNA damage was detected by TUNEL, apoptosis was measured by immunocytochemistry for cleaved caspase-3. Calcium, superoxide, and H₂O₂ were detected by fluorescent indicators and modulated by BAPTA-AM, mtTEMPOL, or Trolox, respectively. Results: pFUS increased TUNEL reactivity (range = 1.6-2.7-fold) in all cell types except C6 and did not induce apoptosis in any cell line. All lines displayed cytosolic Ca²⁺ transients during sonication. pFUS increased superoxide (range = 1.6-2.0-fold) and H₂O₂ (range = 2.3-2.8-fold) in all cell types except C6. BAPTA-AM blocked increased TUNEL reactivity, superoxide and H₂O₂ formation, while Trolox also blocked increased TUNEL reactivity increased after pFUS. mtTEMPOL allowed H₂O₂ formation and did not block increased TUNEL reactivity after pFUS. Unsonicated C6 cells had higher baseline concentrations of cytosolic Ca²⁺, superoxide, and H₂O₂, which were not associated with greater baseline TUNEL reactivity than the other cell lines. Conclusions: Mechanotransduction of pFUS directly induces DNA damage in tumor cells by cytosolic Ca²⁺ transients causing formation of superoxide and subsequently, H₂O₂. These results further suggest potential clinical utility for pFUS. However, the lack of pFUS-induced DNA damage in C6 cells demonstrates a range of potential tumor responses that may arise from physiological differences such as Ca²⁺ or redox homeostasis.

Modulation of Heat-Shock Proteins Mediates Chicken Cell Survival against Thermal Stress

Heat stress is one of the most challenging environmental stresses affecting domestic animal production, particularly commercial poultry, subsequently causing severe yearly economic losses. Heat stress, a major source of oxidative stress, stimulates mitochondrial oxidative stress and cell dysfunction, leading to cell damage and apoptosis. Cell survival under stress conditions needs urgent response mechanisms and the consequent effective reinitiation of cell functions following stress mitigation. Exposure of cells to heat-stress conditions induces molecules that are ready for mediating cell death and survival signals, and for supporting the cell's tolerance and/or recovery from damage. Heat-shock proteins (HSPs) confer cell protection against heat stress via different mechanisms, including developing thermotolerance, modulating apoptotic and antiapoptotic signaling pathways, and regulating cellular redox conditions. These functions mainly depend on the capacity of HSPs to work as molecular chaperones and to inhibit the aggregation of non-native and misfolded proteins. This review sheds light on the key factors in heat-shock responses for protection against cell damage induced by heat stress in chicken.

MR-guided pulsed focused ultrasound improves mesenchymal stromal cell homing to the myocardium

Image-guided pulsed focused ultrasound (pFUS) is a non-invasive technique that can increase tropism of intravenously (IV)-infused mesenchymal stromal cells (MSC) to sonicated tissues. MSC have shown promise for cardiac regenerative medicine strategies but can be hampered by inefficient homing to the myocardium. This study sonicated the left ventricles (LV) in rats with magnetic resonance imaging (MRI)-guided pFUS and examined both proteomic responses and subsequent MSC tropism to treated myocardium. T2-weighted MRI was used for pFUS targeting of the entire LV. pFUS increased numerous pro- and anti-inflammatory cytokines, chemokines, and trophic factors and cell adhesion molecules in the myocardial microenvironment for up to 48 hours post-sonication. Cardiac troponin I and N-terminal pro-B-type natriuretic peptide were elevated in the serum and myocardium. Immunohistochemistry revealed transient hypoxia and immune cell infiltration in pFUS-targeted regions. Myocardial tropism of IV-infused human MSC following pFUS increased twofold-threefold compared with controls. Proteomic and histological changes in myocardium following pFUS suggested a reversible inflammatory and hypoxic response leading to increased tropism of MSC. MR-guided pFUS could represent a non-invasive modality to improve MSC therapies for cardiac regenerative medicine approaches.

Pulsed focused ultrasound enhances the therapeutic effect of mesenchymal stromal cell-derived extracellular vesicles in acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is characterized by rapid failure of renal function and has no curative therapies. Mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) are known to carry therapeutic factors, which have shown promise in regenerative medicine applications, including AKI. However, there remains an unmet need to optimize their therapeutic effect. One potential avenue of optimization lies in pulsed focused ultrasound (pFUS), where tissues-of-interest are treated with sound waves. pFUS has been shown to enhance MSC therapy via increased cell homing, but its effects on cell-free EV therapy remain largely unexplored.

METHODS

We combine pFUS pretreatment of the kidney with MSC-derived EV therapy in a mouse model of cisplatin-induced AKI.

RESULTS

EVs significantly improved kidney function, reduced injury markers, mediated increased proliferation, and reduced inflammation and apoptosis. While pFUS did not enhance EV homing to the kidney, the combined treatment resulted in a superior therapeutic effect compared to either treatment alone. We identified several molecular mechanisms underlying this synergistic therapeutic effect, including upregulation of proliferative signaling (MAPK/ERK, PI3K/Akt) and regenerative pathways (eNOS, SIRT3), as well as suppression of inflammation.

CONCLUSION

Taken together, pFUS may be a strategy for enhancing the therapeutic efficacy of MSC-derived EV treatment for the treatment of AKI.

HSP70-Mediated NLRP3 Inflammasome Suppression Underlies Reversal of Acute Kidney Injury Following Extracellular Vesicle and Focused Ultrasound Combination Therapy

Acute kidney injury (AKI) is the abrupt loss of renal function, for which only supportive therapies exist. Mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) have been shown to be therapeutically effective in treating AKI by spurring endogenous cell proliferation and survival while suppressing inflammation. Pre-treating kidneys with pulsed focused ultrasound (pFUS) has also been shown to enhance MSC therapy for AKI, but its role in MSC-derived EV therapy remains unexplored. Using a mouse model of cisplatin-induced AKI, we show that combination therapy with pFUS and EVs restores physiological and molecular markers of kidney function, more so than either alone. Both pFUS and EVs downregulate heat shock protein 70 (HSP70), the NLRP3 inflammasome, and its downstream pro-inflammatory cytokines IL-1β and IL-18, all of which are highly upregulated in AKI. In vitro knockdown studies suggest that HSP70 is a positive regulator of the NLRP3 inflammasome. Our study therefore demonstrates the ability of pFUS to enhance EV therapy for AKI and provides further mechanistic understanding of their anti-inflammatory and regenerative effects.