Exosome-based delivery of super-repressor IκBα ameliorates kidney ischemia-reperfusion injury

Exploring the clinical transition of engineered exosomes designed for intracellular delivery of therapeutic proteins

Extracellular vesicles, particularly exosomes, have emerged as promising drug delivery systems owing to their unique advantages, such as biocompatibility, immune tolerability, and target specificity. Various engineering strategies have been implemented to harness these innate qualities, with a focus on enhancing the pharmacokinetic and pharmacodynamic properties of exosomes via payload loading and surface engineering for active targeting. This concise review outlines the challenges in the development of exosomes as drug carriers and offers insights into strategies for their effective clinical translation. We also highlight preclinical studies that have successfully employed anti-inflammatory exosomes and suggest future directions for exosome therapeutics. These advancements underscore the potential for integrating exosome-based therapies into clinical practice, heralding promise for future medical interventions.

Self-powered triboelectric-responsive microneedles with controllable release of optogenetically engineered extracellular vesicles for intervertebral disc degeneration repair

Excessive exercise is an etiological factor of intervertebral disc degeneration (IVDD). Engineered extracellular vesicles (EVs) exhibit excellent therapeutic potential for disease-modifying treatments. Herein, we fabricate an exercise self-powered triboelectric-responsive microneedle (MN) assay with the sustainable release of optogenetically engineered EVs for IVDD repair. Mechanically, exercise promotes cytosolic DNA sensing-mediated inflammatory activation in senescent nucleus pulposus (NP) cells (the master cell population for IVD homeostasis maintenance), which accelerates IVDD. TREX1 serves as a crucial nuclease, and disassembly of TRAM1-TREX1 complex disrupts the subcellular localization of TREX1, triggering TREX1-dependent genomic DNA damage during NP cell senescence. Optogenetically engineered EVs deliver TRAM1 protein into senescent NP cells, which effectively reconstructs the elimination function of TREX1. Triboelectric nanogenerator (TENG) harvests mechanical energy and triggers the controllable release of engineered EVs. Notably, an optogenetically engineered EV-based targeting treatment strategy is used for the treatment of IVDD, showing promising clinical potential for the treatment of degeneration-associated disorders.

Trends in Developing Extracellular Vesicle-Based Therapeutics

Extracellular vesicles are nano-sized vesicles surrounded by lipid bilayers, and all cells release them to the extracellular environment for communication. Extracellular vesicles consist of molecules with various biological activities and can play essential roles as therapeutics, so they attract much attention as next-generation modalities to treat various diseases. As extracellular vesicles are cell-derived nanovesicles, they are favorable to be developed as therapeutics, but they also have limitations. In addition, there are a number of things to consider in terms of manufacturing, quality control, non-clinical studies, and clinical trials during the development of extracellular vesicle-based therapeutics. Meanwhile, as much attention has been paid to the potentials of extracellular vesicles as therapeutics, many biopharmaceutical companies are trying to develop extracellular vesicle-based therapeutics. This review will introduce the advantages and limitations of extracellular vesicles as therapeutics. In addition, it will cover things to consider during developing extracellular vesicle-based therapeutics and development cases of extracellular vesicle-based therapeutics.

Annexin-A5 monomer as a membrane repair agent for the treatment of renal ischemia-reperfusion injury

BACKGROUND

Renal ischemia-reperfusion injury (IRI) is one of the causes of acute kidney injury. Annexin A5 (AnxA5), a calcium-dependent cell membrane-binding protein, shows protective effects in various organ IRI models. This study explored the therapeutic effect of exogenous AnxA5 monomer protein on renal IRI and its potential mechanism of action.

METHODS AND RESULTS

Different doses of AnxA5 were injected intravenously to treat bilateral renal IRI in SD rats. This model confirmed the protective effects of AnxA5 on kidney structure and function. In vitro, HK-2 cells were subjected to hypoxia for 12 h, followed by restoration of normal oxygen supply to simulate IRI. In vitro experiments demonstrated the mechanism of action of AnxA5 by measuring cellular activity and permeability. A comparison of the mutant AnxA5 protein M23 and the application of a calcium-free culture medium further validated the protective effect of AnxA5 by forming a network structure.

CONCLUSIONS

Exogenous AnxA5 monomers prevented renal IRI by binding to the damaged renal tubular epithelial cell membrane, forming a two-dimensional network structure to maintain cell membrane integrity, and ultimately prevent cell death.

Delivery-mediated exosomal therapeutics in ischemia-reperfusion injury: advances, mechanisms, and future directions

Ischemia-reperfusion injury (IRI) poses significant challenges across various organ systems, including the heart, brain, and kidneys. Exosomes have shown great potentials and applications in mitigating IRI-induced cell and tissue damage through modulating inflammatory responses, enhancing angiogenesis, and promoting tissue repair. Despite these advances, a more systematic understanding of exosomes from different sources and their biotransport is critical for optimizing therapeutic efficacy and accelerating the clinical adoption of exosomes for IRI therapies. Therefore, this review article overviews the administration routes of exosomes from different sources, such as mesenchymal stem cells and other somatic cells, in the context of IRI treatment. Furthermore, this article covers how the delivered exosomes modulate molecular pathways of recipient cells, aiding in the prevention of cell death and the promotions of regeneration in IRI models. In the end, this article discusses the ongoing research efforts and propose future research directions of exosome-based therapies.

Insights into optimizing exosome therapies for acute skin wound healing and other tissue repair

Exosome therapy holds great promise as a novel approach to improve acute skin wound healing. This review provides a comprehensive overview of the current understanding of exosome biology and its potential applications in acute skin wound healing and beyond. Exosomes, small extracellular vesicles secreted by various stem cells, have emerged as potent mediators of intercellular communication and tissue repair. One advantage of exosome therapy is its ability to avoid potential risks associated with stem cell therapy, such as immune rejection or stem cells differentiating into unwanted cell types. However, further research is necessary to optimize exosome therapy, not only in the areas of exosome isolation, characterization, and engineering, but also in determining the optimal dose, timing, administration, and frequency of exosome therapy. Thus, optimization of exosome therapy is critical for the development of more effective and safer exosome-based therapies for acute skin wound healing and other diseases induced by cancer, ischemia, or inflammation. This review provides valuable insights into the potential of exosome therapy and highlights the need for further research to optimize exosome therapy for clinical use.

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.

The role of hydrogen sulfide regulation of pyroptosis in different pathological processes

Pyroptosis is one kind of programmed cell death in which the cell membrane ruptures and subsequently releases cell contents and pro-inflammatory cytokines including IL-1β and IL-18. Pyroptosis is caused by many types of pathological stimuli, such as hyperglycemia (HG), oxidative stress, and inflammation, and is mediated by gasdermin (GSDM) protein family. Increasing evidence indicates that pyroptosis plays an important role in multiple diseases, such as cancer, kidney diseases, inflammatory diseases, and cardiovascular diseases. Therefore, the regulation of pyroptosis is crucial for the occurrence, development, and treatment of many diseases. Hydrogen sulfide (H2S) is a biologically active gasotransmitter following carbon monoxide (CO) and nitrogen oxide (NO) in mammalian tissues. So far, three enzymes, including 3-mercaptopyruvate sulphurtransferase (3-MST), cystathionine γ- Lyase (CSE), and Cystine β-synthesis enzyme (CBS), have been found to catalyze the production of endogenous H2S in mammals. H2S has been reported to have multiple biological functions including anti-inflammation, anti-oxidative stress, anti-apoptosis and so on. Hence, H2S is involved in various physiological and pathological processes. In recent years, many studies have demonstrated that H2S plays a critical role by regulating pyroptosis in various pathological processes, such as ischemia-reperfusion injury, alcoholic liver disease, and diabetes cardiomyopathy. However, the relevant mechanism has not been completely understood. Therefore, elucidating the mechanism by which H2S regulates pyroptosis in diseases will help understand the pathogenesis of multiple diseases and provide important new avenues for the treatment of many diseases. Here, we reviewed the progress of H2S regulation of pyroptosis in different pathological processes, and analyzed the molecular mechanism in detail to provide a theoretical reference for future related research.

Recent Advances in Nanomaterials for the Treatment of Acute Kidney Injury

Acute kidney injury (AKI) is a serious clinical syndrome with high morbidity, elevated mortality, and poor prognosis, commonly considered a "sword of Damocles" for hospitalized patients, especially those in intensive care units. Oxidative stress, inflammation, and apoptosis, caused by the excessive production of reactive oxygen species (ROS), play a key role in AKI progression. Hence, the investigation of effective and safe antioxidants and inflammatory regulators to scavenge overexpressed ROS and regulate excessive inflammation has become a promising therapeutic option. However, the unique physiological structure and complex pathological alterations in the kidneys render traditional therapies ineffective, impeding the residence and efficacy of most antioxidant and anti-inflammatory small molecule drugs within the renal milieu. Recently, nanotherapeutic interventions have emerged as a promising and prospective strategy for AKI, overcoming traditional treatment dilemmas through alterations in size, shape, charge, and surface modifications. This Review succinctly summarizes the latest advancements in nanotherapeutic approaches for AKI, encompassing nanozymes, ROS scavenger nanomaterials, MSC-EVs, and nanomaterials loaded with antioxidants and inflammatory regulator. Following this, strategies aimed at enhancing biocompatibility and kidney targeting are introduced. Furthermore, a brief discussion on the current challenges and future prospects in this research field is presented, providing a comprehensive overview of the evolving landscape of nanotherapeutic interventions for AKI.

Engineered Extracellular Vesicles in Chronic Kidney Diseases: A Comprehensive Review

Chronic kidney diseases (CKD) present a formidable global health challenge, characterized by a deficiency of effective treatment options. Extracellular vesicles (EVs), recognized as multifunctional drug delivery systems in biomedicine, have gained accumulative interest. Specifically, engineered EVs have emerged as a promising therapeutic approach for targeted drug delivery, potentially addressing the complexities of CKD management. In this review, we systematically dissect EVs, elucidating their classification, biogenesis, composition, and cargo molecules. Furthermore, we explore techniques for EV engineering and strategies for their precise renal delivery, focusing on cargo loading and transportation, providing a comprehensive perspective. Moreover, this review also discusses and summarizes the diverse therapeutic applications of engineered EVs in CKD, emphasizing their anti-inflammatory, immunomodulatory, renoprotective, and tissue-regenerating effects. It critically evaluates the challenges and limitations in translating EV therapies from laboratory settings to clinical applications, while outlining future prospects and emerging trends.

NF-κB in biology and targeted therapy: new insights and translational implications

NF-κB signaling has been discovered for nearly 40 years. Initially, NF-κB signaling was identified as a pivotal pathway in mediating inflammatory responses. However, with extensive and in-depth investigations, researchers have discovered that its role can be expanded to a variety of signaling mechanisms, biological processes, human diseases, and treatment options. In this review, we first scrutinize the research process of NF-κB signaling, and summarize the composition, activation, and regulatory mechanism of NF-κB signaling. We investigate the interaction of NF-κB signaling with other important pathways, including PI3K/AKT, MAPK, JAK-STAT, TGF-β, Wnt, Notch, Hedgehog, and TLR signaling. The physiological and pathological states of NF-κB signaling, as well as its intricate involvement in inflammation, immune regulation, and tumor microenvironment, are also explicated. Additionally, we illustrate how NF-κB signaling is involved in a variety of human diseases, including cancers, inflammatory and autoimmune diseases, cardiovascular diseases, metabolic diseases, neurological diseases, and COVID-19. Further, we discuss the therapeutic approaches targeting NF-κB signaling, including IKK inhibitors, monoclonal antibodies, proteasome inhibitors, nuclear translocation inhibitors, DNA binding inhibitors, TKIs, non-coding RNAs, immunotherapy, and CAR-T. Finally, we provide an outlook for research in the field of NF-κB signaling. We hope to present a stereoscopic, comprehensive NF-κB signaling that will inform future research and clinical practice.

Macrophage Ontogeny, Phenotype, and Function in Ischemia Reperfusion-Induced Injury and Repair

AKI is characterized by a sudden, and usually reversible, decline in kidney function. In mice, ischemia-reperfusion injury (IRI) is commonly used to model the pathophysiologic features of clinical AKI. Macrophages are a unifying feature of IRI as they regulate both the initial injury response as well as the long-term outcome following resolution of injury. Initially, macrophages in the kidney take on a proinflammatory phenotype characterized by the production of inflammatory cytokines, such as CCL2 (monocyte chemoattractant protein 1), IL-6, IL-1 β , and TNF- α . Release of these proinflammatory cytokines leads to tissue damage. After resolution of the initial injury, macrophages take on a reparative role, aiding in tissue repair and restoration of kidney function. By contrast, failure to resolve the initial injury results in prolonged inflammatory macrophage accumulation and increased kidney damage, fibrosis, and the eventual development of CKD. Despite the extensive amount of literature that has ascribed these functions to M1/M2 macrophages, a recent paradigm shift in the macrophage field now defines macrophages on the basis of their ontological origin, namely monocyte-derived and tissue-resident macrophages. In this review, we focus on macrophage phenotype and function during IRI-induced injury, repair, and transition to CKD using both the classic (M1/M2) and novel (ontological origin) definition of kidney macrophages.

Exosome-Mediated Impact on Systemic Metabolism

Exosomes are small extracellular vesicles that carry lipids, proteins, and microRNAs (miRNAs). They are released by all cell types and can be found not only in circulation but in many biological fluids. Exosomes are essential for interorgan communication because they can transfer their contents from donor to recipient cells, modulating cellular functions. The miRNA content of exosomes is responsible for most of their biological effects, and changes in exosomal miRNA levels can contribute to the progression or regression of metabolic diseases. As exosomal miRNAs are selectively sorted and packaged into exosomes, they can be useful as biomarkers for diagnosing diseases. The field of exosomes and metabolism is expanding rapidly, and researchers are consistently making new discoveries in this area. As a result, exosomes have great potential for a next-generation drug delivery platform for metabolic diseases.

Exosomes-Mediated Signaling Pathway: A New Direction for Treatment of Organ Ischemia-Reperfusion Injury

Ischemia reperfusion (I/R) is a common pathological process which occurs mostly in organs like the heart, brain, kidney, and lung. The injury caused by I/R gradually becomes one of the main causes of fatal diseases, which is an urgent clinical problem to be solved. Although great progress has been made in therapeutic methods, including surgical, drug, gene therapy, and transplant therapy for I/R injury, the development of effective methods to cure the injury remains a worldwide challenge. In recent years, exosomes have attracted much attention for their important roles in immune response, antigen presentation, cell migration, cell differentiation, and tumor invasion. Meanwhile, exosomes have been shown to have great potential in the treatment of I/R injury in organs. The study of the exosome-mediated signaling pathway can not only help to reveal the mechanism behind exosomes promoting reperfusion injury recovery, but also provide a theoretical basis for the clinical application of exosomes. Here, we review the research progress in utilizing various exosomes from different cell types to promote the healing of I/R injury, focusing on the classical signaling pathways such as PI3K/Akt, NF-κB, Nrf2, PTEN, Wnt, MAPK, toll-like receptor, and AMPK. The results suggest that exosomes regulate these signaling pathways to reduce oxidative stress, regulate immune responses, decrease the expression of inflammatory cytokines, and promote tissue repair, making exosomes a competitive emerging vector for treating I/R damage in organs.

Intracellular Protein Delivery: Approaches, Challenges, and Clinical Applications

Protein biologics are powerful therapeutic agents with diverse inhibitory and enzymatic functions. However, their clinical use has been limited to extracellular applications due to their inability to cross plasma membranes. Overcoming this physiological barrier would unlock the potential of protein drugs for the treatment of many intractable diseases. In this review, we highlight progress made toward achieving cytosolic delivery of recombinant proteins. We start by first considering intracellular protein delivery as a drug modality compared to existing Food and Drug Administration-approved drug modalities. Then, we summarize strategies that have been reported to achieve protein internalization. These techniques can be broadly classified into 3 categories: physical methods, direct protein engineering, and nanocarrier-mediated delivery. Finally, we highlight existing challenges for cytosolic protein delivery and offer an outlook for future advances.

Efficacy of Allogeneic and Xenogeneic Exosomes for the Treatment of Canine Atopic Dermatitis: A Pilot Study

Canine atopic dermatitis (CAD) is a genetically predisposed inflammatory pruritic skin disease. The available treatments for CAD have several adverse effects and vary in efficacy, indicating the need for the development of improved treatments. In this study, we aimed to elucidate the therapeutic effects of allogeneic and xenogeneic exosomes on CAD. Six laboratory beagle dogs with CAD were randomly assigned to three treatment groups: control, canine exosome (cExos), or human exosome (hExos) groups. Dogs in the cExos and hExos groups were intravenously administered 1.5 mL of cExos (5 × 1010) and hExos (7.5 × 1011) solutions, respectively, while those in the control group were administered 1.5 mL of normal saline three times per week for 4 weeks. Skin lesion score and transepidermal water loss decreased in cExos and hExos groups compared with those in the control group. The exosome treatments decreased the serum levels of inflammatory cytokines (interferon-γ, interleukin-2, interleukin-4, interleukin-12, interleukin-13, and interleukin-31) but increased those of anti-inflammatory cytokines (interleukin-10 and transforming growth factor-β), indicating the immunomodulatory effect of exosomes. Skin microbiome analysis revealed that the exosome treatments alleviated skin bacterial dysbiosis. These results suggest that allogeneic and xenogeneic exosome therapy may alleviate CAD in dogs.

Exosome-mediated delivery of super-repressor IκBα alleviates inflammation and joint damages in rheumatoid arthritis

BACKGROUND

This study aims to investigate the potential anti-inflammatory effects of exosomes engineered to carry super-repressor IκB (Exo-srIκB), an exosome-based NF-κB inhibitor, in the context of RA.

METHODS

Peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) were collected from patients diagnosed with RA and treated with Exo-srIκB to test the therapeutic potential. Flow cytometry analysis was performed to assess the production of inflammatory cytokines (IL-17A and GM-CSF) by the cells. ELISA was utilized to measure the levels of TNF-α, IL-17A, IL-6, and GM-CSF. Arthritis was induced in SKG mice by intraperitoneal injection of curdlan. DBA/1 J mice were used in collagen-induced arthritis (CIA) experiments. After the development of arthritis, mice were injected with either Exo-Naïve (control exosome) or Exo-srIκB. Arthritis scores were recorded biweekly, and histological observations of the ankle joint were conducted using H&E and safranin-O staining. Additionally, bone erosion was evaluated using micro-CT imaging.

RESULTS

In the ex vivo study involving human PBMCs and SFMCs, treatment with Exo-srIκB demonstrated a notable reduction in inflammatory cytokines. Furthermore, in both the SKG and CIA models, Exo-srIκB treatment exhibited significant reductions in inflammation, cartilage destruction, and bone erosion within the joint tissues when compared to the Exo-Naive control group. Additionally, the radiographic score assessed through microCT showed a significant decrease compared to the Exo-Naive control group.

CONCLUSION

Overall, these findings suggest that Exo-srIκB possesses anti-inflammatory properties in human RA cells and animal models, making it a promising therapeutic candidate for the treatment of RA.

Ambra1 in exosomes secreted by HK-2 cells damaged by supersaturated oxalate induce mitophagy and autophagy-ferroptosis in normal HK-2 cells to participate in the occurrence of kidney stones

Injury to the renal tubular epithelium has emerged as a leading factor underlying the formation of kidney stones. Indeed, epithelial cell damage contributes to the adherence and aggregation of crystals, thereby accelerating the formation of renal stones. Meanwhile, exosomes play an instrumental role in cellular communication, including DNA, RNA, mRNA, etc. In this study, homogenous cells were treated with exosomes derived from damaged cells in an attempt to establish "positive feedback" of cell damage, and the desired results were achieved. To begin, a serum-free medium and supersaturated concentrations of oxalate were added to the HK-2 cell line, and then exosomes were isolated from the two groups for analysis and comparison, and the autophagy-related gene Ambra1 (autophagy and beclin-1 regulator 1) was detected. Subsequently, normal HK-2 cells were treated with exosomes, and the related indexes of autophagy, ferroptosis and mitophagy were determined. Thereafter, Ambra1 was knocked down in exosome-derived HK-2 cells, resulting in the down-regulation of Ambra1 expression in exosomes produced by HK-2 cells following oxalate intervention. Thereafter, the ability of exosomes to stimulate autophagy, mitophagy and ferroptosis was re-evaluated in HK-2 cells after Ambra1 knockdown. The results corroborated that exosomes secreted by oxalate-treated HK-2 can directly elevate autophagy, ferroptosis and mitophagy levels in normal cells, and this effect was significantly mitigated following Ambra1 knockdown within exosomes. Meanwhile, exosomes-induced autophagy and ferroptosis were alleviated after knockdown of beclin-1 in recipient HK-2 cells. These results further suggest that beclin-1 plays a critical role in the process of exosome-induced autophagy-ferroptosis.

Engineered Exosomes for Drug Delivery in Cancer Therapy: A Promising Approach and Application

A significant amount of research effort is currently focused on investigating the role of exosomes in various cancers. These tiny vesicles, apart from acting as biomarkers, also play a crucial role in tumor formation and development. Several studies have demonstrated that exosomes can be a drug delivery vehicle for cancer therapy. In this paper, we highlight the key advantages of exosomes as a drug delivery candidate, with a particular focus on their low immunogenicity, natural targeting ability and suitable mechanical properties. Furthermore, we propose that the selection of appropriate exosomes and drug loading methods based on therapeutic goals and product heterogeneity is essential for preparing engineered exosomes. We comprehensively analyzed the superiorities of current drug-loading methods to improve the creation of designed exosomes. Moreover, we systematically review the applications of engineered exosomes in various therapies such as immunotherapy, gene therapy, protein therapy, chemotherapy, indicating that engineered exosomes have the potential to be reliable and, safe drug carriers that can address the unmet needs in cancer clinical practice.

Alleviation of ischemia-reperfusion induced renal injury by chemically modified SOD2 mRNA delivered via lipid nanoparticles

Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury, which is a serious clinical condition with no effective pharmacological treatment. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) significantly alleviate kidney IRI; however, the underlying mechanisms and key molecules conferring renoprotection remain elusive. In this study, we characterized the protein composition of MSC-EVs using a proteomics approach and found that mitochondrial protein superoxide dismutase 2 (SOD2) was enriched in MSC-EVs. Using lipid nanoparticles (LNP), we successfully delivered chemically modified SOD2 mRNA into kidney cells and mice with kidney IRI. We demonstrated that SOD2 mRNA-LNP treatment decreased cellular reactive oxygen species (ROS) in cultured cells and ameliorated renal damage in IRI mice, as indicated by reduced levels of serum creatinine and restored tissue integrity compared with the control mRNA-LNP-injected group. Thus, the modulation of mitochondrial ROS levels through SOD2 upregulation by SOD2 mRNA-LNP delivery could be a novel therapeutic method for ischemia-reperfusion-induced acute kidney injury.

Satellite cell-derived exosome-mediated delivery of microRNA-23a/27a/26a cluster ameliorates the renal tubulointerstitial fibrosis in mouse diabetic nephropathy

Renal tubulointerstitial fibrosis (TIF) is considered as the final convergent pathway of diabetic nephropathy (DN) without effective therapies currently. MiRNAs play a key role in fibrotic diseases and become promising therapeutic targets for kidney diseases, while miRNA clusters, formed by the cluster arrangement of miRNAs on chromosomes, can regulate diverse biological functions alone or synergistically. In this study, we developed clustered miR-23a/27a/26a-loaded skeletal muscle satellite cells-derived exosomes (Exos) engineered with RVG peptide, and investigated their therapeutic efficacy in a murine model of DN. Firstly, we showed that miR-23a-3p, miR-26a-5p and miR-27a-3p were markedly decreased in serum samples of DN patients using miRNA sequencing. Meanwhile, we confirmed that miR-23a-3p, miR-26a-5p and miR-27a-3p were primarily located in proximal renal tubules and highly negatively correlated with TIF in db/db mice at 20 weeks of age. We then engineered RVG-miR-23a/27a/26a cluster loaded Exos derived from muscle satellite cells, which not only enhanced the stability of miR-23a/27a/26a cluster, but also efficiently delivered more miR-23a/27a/26a cluster homing to the injured kidney. More importantly, administration of RVG-miR-23a/27a/26a-Exos (100 μg, i.v., once a week for 8 weeks) significantly ameliorated tubular injury and TIF in db/db mice at 20 weeks of age. We revealed that miR-23a/27a/26a-Exos enhanced antifibrotic effects by repressing miRNA cluster-targeting Lpp simultaneously, as well as miR-27a-3p-targeting Zbtb20 and miR-26a-5p-targeting Klhl42, respectively. Knockdown of Lpp by injection of AAV-Lpp-RNAi effectively ameliorated the progression of TIF in DN mice. Taken together, we established a novel kidney-targeting Exo-based delivery system by manipulating the miRNA-23a/27a/26a cluster to ameliorate TIF in DN, thus providing a promising therapeutic strategy for DN.

Engineered exosomes for tissue regeneration: from biouptake, functionalization and biosafety to applications

Exosomes are increasingly recognized as important effector molecules that regulate intercellular signaling pathways. Notably, certain types of exosomes can induce therapeutic responses, including cell proliferation, angiogenesis, and tissue repair. The use of exosomes in therapy is a hot spot in current research, especially in regenerative medicine. Despite the therapeutic potential, problems have hindered their success in clinical applications. These shortcomings include low concentration, poor targeting and limited loading capability. To fully realize their therapeutic potential, certain modifications are needed in native exosomes. In the present review, we summarize the exosome modification and functionalization strategies. In addition, we provide an overview of potential clinical applications and highlight the issues associated with the biosafety and biocompatibility of engineered exosomes in applications.

Hypoxic regulation of extracellular vesicles: Implications for cancer therapy

Extracellular vesicles (EVs) play a pivotal role in intercellular communication and have been implicated in cancer progression. Hypoxia, a pervasive hallmark of cancer, is known to regulate EV biogenesis and function. Hypoxic EVs contain a specific set of proteins, nucleic acids, lipids, and metabolites, capable of reprogramming the biology and fate of recipient cells. Enhancing the intrinsic therapeutic efficacy of EVs can be achieved by strategically modifying their structure and contents. Moreover, the use of EVs as drug delivery vehicles holds great promise for cancer treatment. However, various hurdles must be overcome to enable their clinical application as cancer therapeutics. In this review, we aim to discuss the current knowledge on the hypoxic regulation of EVs. Additionally, we will describe the underlying mechanisms by which EVs contribute to cancer progression in hypoxia and outline the progress and limitations of hypoxia-related EV therapeutics for cancer.

Update on current and potential application of extracellular vesicles in kidney transplantation

Kidney transplantation (KT) is the best treatment for end-stage kidney disease. However, early diagnosis of graft injury remains challenging, mainly because of the lack of accurate and noninvasive diagnostic techniques. Improving graft outcomes is equally demanding, as is the development of innovative therapies. Many research efforts are focusing on extracellular vesicles, cellular particles free in each body fluid that have shown promising results as precise markers of damage and potential therapeutic targets in many diseases, including the renal field. In fact, through their receptors and cargo, they act in damage response and immune modulation. In transplantation, they may be used to determine organ quality and aging, the presence of delayed graft function, rejection, and many other transplant-related pathologies. Moreover, their low immunogenicity and safe profile make them ideal for drug delivery and the development of therapies to improve KT outcomes. In this review, we summarize current evidence about extracellular vesicles in KT, starting with their characteristics and major laboratory techniques for isolation and characterization. Then, we discuss their use as potential markers of damage and as therapeutic targets, discussing their promising use in clinical practice as a form of liquid biopsy.

CD8 T Cell-Derived Exosomal miR-186-5p Elicits Renal Inflammation via Activating Tubular TLR7/8 Signal Axis

T cells play an important role in the development of focal segmental glomerulosclerosis (FSGS). The mechanism underlying such T cell-based kidney disease, however, remains elusive. Here the authors report that activated CD8 T cells elicit renal inflammation and tissue injury via releasing miR-186-5p-enriched exosomes. Continuing the cohort study identifying the correlation of plasma level of miR-186-5p with proteinuria in FSGS patients, it is demonstrated that circulating miR-186-5p is mainly derived from activated CD8 T cell exosomes. Renal miR-186-5p, which is markedly increased in FSGS patients and mice with adriamycin-induced renal injury, is mainly delivered by CD8 T cell exosomes. Depleting miR-186-5p strongly attenuates adriamycin-induced mouse renal injury. Supporting the function of exosomal miR-186-5p as a key circulating pathogenic factor, intravenous injection of miR-186-5p or miR-186-5p-containing T cell exosomes results in mouse renal inflammation and tissue injury. Tracing the injected T cell exosomes shows their preferential distribution in mouse renal tubules, not glomerulus. Mechanistically, miR-186-5p directly activates renal tubular TLR7/8 signal and initiates tubular cell apoptosis. Mutating the TLR7-binding sequence on miR-186-5p or deleting mouse TLR7 largely abolishes renal tubular injuries induced by miR-186-5p or adriamycin. These findings reveal a causative role of exosomal miR-186-5p in T cell-mediated renal dysfunction.

Mackinawite nanozymes as reactive oxygen species scavengers for acute kidney injury alleviation

BACKGROUND

Iron sulfide nanomaterials have been successfully employed as therapeutic agents for bacterial infection therapy and catalytic-ferroptosis synergistic tumor therapy due to their unique structures, physiochemical properties, and biocompatibility. However, biomedical research and understanding of the biological functions of iron sulfides are insufficient, and how iron sulfide nanomaterials affect reactive oxygen species (ROS) in diseases remains unknown. Acute kidney injury (AKI) is associated with high levels of ROS, and therefore nanomedicine-mediated antioxidant therapy has emerged as a novel strategy for its alleviation.

RESULTS

Here, mackinawite nanozymes were synthesized from glutathione (GSH) and iron ions (Fe3+) (denoted as GFeSNs) using a hydrothermal method, and then evaluated as ROS scavengers for ROS-related AKI treatment. GFeSNs showed broad-spectrum ROS scavenging ability through synergistic interactions of multiple enzymes-like and hydrogen polysulfide-releasing properties. Furthermore, both in vitro and in vivo experiments demonstrated that GFeSNs exhibited outstanding cytoprotective effects against ROS-induced damage at extremely low doses and significantly improved treatment outcomes in AKI.

CONCLUSIONS

Given the synergetic antioxidant properties and high biocompatibility, GFeSNs exhibit great potential for the treatment of AKI and other ROS-associated diseases.

A report on the International Society for Cell & Gene Therapy 2022 Scientific Signature Series, "Therapeutic advances with native and engineered human extracellular vesicles"

The International Society for Cell & Gene Therapy Scientific Signature Series event "Therapeutic Advances With Native and Engineered Human EVs" took place as part of the International Society for Cell & Gene Therapy 2022 Annual Meeting, held from May 4 to 7, 2022, in San Francisco, California, USA. This was the first signature series event on extracellular vesicles (EVs) and a timely reflection of the growing interest in EVs, including both native and engineered human EVs, for therapeutic applications. The event successfully gathered academic and industrial key opinion leaders to discuss the current state of the art in developing and understanding native and engineered EVs and applying our knowledge toward advancing EV therapeutics. Latest advancements in understanding the mechanisms by which native and engineered EVs exert their therapeutic effects against different diseases in animal models were presented, with some diseases such as psoriasis and osteoarthritis already reaching clinical testing of EVs. The discussion also covered various aspects relevant to advancing the clinical translation of EV therapies, including EV preparation, manufacturing, consistency, site(s) of action, route(s) of administration, and luminal cargo delivery of RNA and other compounds.

Exosome-Based Drug Delivery: Translation from Bench to Clinic

Exosome-based drug delivery is emerging as a promising field with the potential to revolutionize therapeutic interventions. Exosomes, which are small extracellular vesicles released by various cell types, have attracted significant attention due to their unique properties and natural ability to transport bioactive molecules. These nano-sized vesicles, ranging in size from 30 to 150 nm, can effectively transport a variety of cargoes, including proteins, nucleic acids, and lipids. Compared to traditional drug delivery systems, exosomes exhibit unique biocompatibility, low immunogenicity, and reduced toxicity. In addition, exosomes can be designed and tailored to improve targeting efficiency, cargo loading capacity, and stability, paving the way for personalized medicine and precision therapy. However, despite the promising potential of exosome-based drug delivery, its clinical application remains challenging due to limitations in exosome isolation and purification, low loading efficiency of therapeutic cargoes, insufficient targeted delivery, and rapid elimination in circulation. This comprehensive review focuses on the transition of exosome-based drug delivery from the bench to clinic, highlighting key aspects, such as exosome structure and biogenesis, cargo loading methods, surface engineering techniques, and clinical applications. It also discusses challenges and prospects in this emerging field.

Soluble thrombomodulin alleviates Diquat-induced acute kidney injury by inhibiting the HMGB1/IκBα/NF-κB signalling pathway

Our research aimed to investigate whether soluble thrombomodulin (sTM) relieved Diquat (DQ)-induced acute kidney injury (AKI) via HMGB1/IκBα/NF-κB signaling pathways. An AKI rat model was constructed using DQ. Pathological changes in renal tissue were detected by HE and Masson staining. Gene expression was determined using qRT-PCR, IHC, and western blotting. Cell activity and apoptosis were analysed using CCK-8 and Flow cytometry, respectively. An abnormal kidney structure was observed in DQ rats. The levels of blood urea nitrogen (BUN), creatinine (CRE), uric acid (UA), oxidative stress, and inflammatory responses in the DQ group increased on the 7th day but decreased on the 14th day, compared with the control group. Additionally, HMGB1, sTM, and NF-kappaB (NF-κB) expression had increased in the DQ group compared with the control group, while the IκKα and IκB-α levels had decreased. In addition, sTM relieved the damaging effects of diquat on renal tubular epithelial cell viability, apoptosis, and the inflammatory response. The levels of HMGB1, TM, and NF-κB mRNA and protein were significantly decreased in the DQ + sTM group compared with the DQ group. These findings indicated that sTM could relieve Diquat-induced AKI through HMGB1/IκBα/NF-κB signaling pathways, which provides a treatment strategy for Diquat-induced AKI.

An update on renal fibrosis: from mechanisms to therapeutic strategies with a focus on extracellular vesicles

The increasing prevalence of chronic kidney disease (CKD) is a major global public health concern. Despite the complicated pathogenesis of CKD, renal fibrosis represents the most common pathological condition, comprised of progressive accumulation of extracellular matrix in the diseased kidney. Over the last several decades, tremendous progress in understanding the mechanism of renal fibrosis has been achieved, and corresponding potential therapeutic strategies targeting fibrosis-related signaling pathways are emerging. Importantly, extracellular vesicles (EVs) contribute significantly to renal inflammation and fibrosis by mediating cellular communication. Increasing evidence suggests the potential of EV-based therapy in renal inflammation and fibrosis, which may represent a future direction for CKD therapy.

Extracellular Vesicles as Drug Delivery Systems in Organ Transplantation: The Next Frontier

Extracellular vesicles are lipid bilayer-delimited nanoparticles excreted into the extracellular space by all cells. They carry a cargo rich in proteins, lipids and DNA, as well as a full complement of RNA species, which they deliver to recipient cells to induce downstream signalling, and they play a key role in many physiological and pathological processes. There is evidence that native and hybrid EVs may be used as effective drug delivery systems, with their intrinsic ability to protect and deliver a functional cargo by utilising endogenous cellular mechanisms making them attractive as therapeutics. Organ transplantation is the gold standard for treatment for suitable patients with end-stage organ failure. However, significant challenges still remain in organ transplantation; prevention of graft rejection requires heavy immunosuppression and the lack of donor organs results in a failure to meet demand, as manifested by growing waiting lists. Pre-clinical studies have demonstrated the ability of EVs to prevent rejection in transplantation and mitigate ischemia reperfusion injury in several disease models. The findings of this work have made clinical translation of EVs possible, with several clinical trials actively recruiting patients. However, there is much to be uncovered, and it is essential to understand the mechanisms behind the therapeutic benefits of EVs. Machine perfusion of isolated organs provides an unparalleled platform for the investigation of EV biology and the testing of the pharmacokinetic and pharmacodynamic properties of EVs. This review classifies EVs and their biogenesis routes, and discusses the isolation and characterisation methods adopted by the international EV research community, before delving into what is known about EVs as drug delivery systems and why organ transplantation represents an ideal platform for their development as drug delivery systems.

Cobaltosic oxide-polyethylene glycol-triphenylphosphine nanoparticles ameliorate the acute-to-chronic kidney disease transition by inducing BNIP3-mediated mitophagy

Accumulating evidence highlights mitochondrial dysfunction as a crucial factor in the pathogenesis of acute kidney injury (AKI); thus, novel therapeutic strategies maintaining mitochondrial homeostasis are highly anticipated. Recent studies have shown that cobaltosic oxide has peroxidase-like catalytic activities, although its role and mechanism remain elusive in AKI. In the present study, we synthesized and identified cobaltosic oxide-polyethylene glycol-triphenylphosphine (COPT) nanoparticles by conjugating cobaltosic oxide with polyethylene glycol and triphenylphosphine, to improve its biocompatibility and mitochondria-targeting property. We found that COPT preferentially accumulated in the kidney proximal tubule cells, and significantly alleviated ischemic AKI in mouse models and gentamicin induced-AKI in the zebrafish model. COPT also inhibited the transition from AKI to chronic kidney disease (CKD), with few side effects. Further studies demonstrated that COPT localized in the mitochondria, and ameliorated hypoxia-reoxygenation-mediated mitochondrial damage through enhancing mitophagy in vitro and in vivo. Mechanistically, COPT dose-dependently induced the expression of Bcl-2/adenovirus E1B 19-kDa interacting protein (BNIP3), while knockdown of BNIP3 attenuated COPT-induced mitophagic flux and mitochondrial protection. Thus, our findings suggest that COPT nanoparticles ameliorate AKI and its progression to CKD through inducing BNIP3-mediated mitophagy, indicating that COPT may serve as a promising mitochondria-targeting therapeutic agent against AKI.

Conditioned Medium - Is it an Undervalued Lab Waste with the Potential for Osteoarthritis Management?

BACKGROUND

The approaches currently used in osteoarthritis (OA) are mainly short-term solutions with unsatisfactory outcomes. Cell-based therapies are still controversial (in terms of the sources of cells and the results) and require strict culture protocol, quality control, and may have side-effects. A distinct population of stromal cells has an interesting secretome composition that is underrated and commonly ends up as biological waste. Their unique properties could be used to improve the existing techniques due to protective and anti-ageing properties.

SCOPE OF REVIEW

In this review, we seek to outline the advantages of the use of conditioned media (CM) and exosomes, which render them superior to other cell-based methods, and to summarise current information on the composition of CM and their effect on chondrocytes.

MAJOR CONCLUSIONS

CM are obtainable from a variety of mesenchymal stromal cell (MSC) sources, such as adipose tissue, bone marrow and umbilical cord, which is significant to their composition. The components present in CMs include proteins, cytokines, growth factors, chemokines, lipids and ncRNA with a variety of functions. In most in vitro and in vivo studies CM from MSCs had a beneficial effect in enhance processes associated with chondrocyte OA pathomechanism.

GENERAL SIGNIFICANCE

This review summarises the information available in the literature on the function of components most commonly detected in MSC-conditioned media, as well as the effect of CM on OA chondrocytes in in vitro culture. It also highlights the need to standardise protocols for obtaining CM, and to conduct clinical trials to transfer the effects obtained in vitro to human subjects.

Exosome-Based Delivery of Super-Repressor IκBα Alleviates Alcohol-Associated Liver Injury in Mice

Activation of Kupffer cells (KCs) by gut-derived lipopolysaccharide (LPS) instigates nuclear factor-κB (NF-κB)-mediated inflammatory responses in alcohol-associated liver diseases (ALD). Here, we utilized a novel optogenetically engineered exosome technology called 'exosomes for protein loading via optically reversible protein-protein interactions (EXPLOR)' to efficiently deliver the super-repressor IκB-loaded exosomes (Exo-srIκB) to the liver and examined its therapeutic potential in acute-on-chronic alcohol-associated liver injury. We detected enhanced uptake of DiI-labeled Exo-srIκB by LPS-treated inflammatory KCs, which suppressed LPS-induced inflammatory gene expression levels. In animal experiments, a single intravenous injection of Exo-srIκB prior to alcohol binge drinking significantly attenuated alcohol-associated hepatic steatosis and infiltration of neutrophils and macrophages but not a liver injury. Notably, three consecutive days of Exo-srIκB injection remarkably reduced alcohol-associated liver injury, steatosis, apoptosis of hepatocytes, fibrosis-related gene expression levels in hepatic stellate cells, infiltration of neutrophils and macrophages, and inflammatory gene expression levels in hepatocytes and KCs. In particular, the above effects occurred with inhibition of nuclear translocation of NF-κB in liver tissues, and these beneficial effects of Exo-srIκB on ALD were shown regardless of doses. Our results suggest an exosome-based modulation of NF-κB activity in KCs by Exo-srIκB as a novel and efficient therapeutic approach in ALD.

Nanosystems for oxidative stress regulation in the anti-inflammatory therapy of acute kidney injury

Acute kidney injury (AKI) is a clinical syndrome that results from a rapid decline in renal structure or renal functional impairment with the main pathological feature of sublethal and lethal damage to renal tubular cells. However, many potential therapeutic agents cannot achieve the desired therapeutic effect because of their poor pharmacokinetics and short retention time in the kidneys. With the recent emergence and progress of nanotechnology, nanodrugs with unique physicochemical properties could prolong circulation time, enhance efficient targeted delivery, and elevate the accumulation of therapeutics that can cross the glomerular filtration barrier and indicate comprehensive application prospects in the prevention and treatment of AKI. In this review, various types of nanosystems (such as liposomes, polymeric nanosystems, inorganic nanoparticles and cell-derived extracellular vesicles) are designed and applied to improve the pharmacokinetics of drug formation, which could further relieve the burden on the kidneys caused by the final cumulative dose of drugs in conventional treatments. Moreover, the passive or active targeting effect of nanosystems can also reduce the total therapeutic dose and off-target adverse effects on other organs. Nanodelivery systems for treating AKI that alleviate oxidative stress-induced renal cell damage and regulate the inflammatory kidney microenvironment are summarized.

Kluyveromyces marxianus Ameliorates High-Fat-Diet-Induced Kidney Injury by Affecting Gut Microbiota and TLR4/NF-κB Pathway in a Mouse Model

Objectives. The effects of Kluyveromyces marxianus on high-fat diet- (HFD-) induced kidney injury (KI) were explored. Methods. HFD-induced KI model was established using male C57BL/6 mice and treated with K. marxianus JLU-1016 and acid-resistant (AR) strain JLU-1016A. Glucose tolerance was evaluated via an oral glucose tolerance test (OGTT). KI was measured using Hematoxylin and Eosin (H&E) staining and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analysis. The chemical indexes were analyzed, including lipid profiles, inflammatory cytokines, and creatinine. The levels of Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) or phospho-NF-κB p65 (Ser536) and alpha inhibitor of NF-κB (IκBα) were measured using qPCR and Western blot. The gut microbiota was sequenced using high-throughput sequencing. Results. HFD induction increased OGTT value, KI severity, oxidative stress, inflammatory cytokines, oxidative stress, apoptotic rate, creatinine levels, and the expression of TLR4/NF-κB, phospho-NF-κB p65 (Ser536), and IκBα deteriorated lipid profiles ( $P<0.05$ ) and reduced gut microbiota abundance. K. marxianus treatment ameliorated HFD-induced metabolic disorders and reversed these parameters ( $P<0.05$ ). Compared with the control, HFD induction increased the proportion of Firmicutes but reduced the proportion of Bacteroidetes and Lactobacillus. K. marxianus JLU-1016 and AR strain JLU-1016A treatments improved gut microbiota by reducing the proportion of Firmicutes and increasing the proportion of Bacteroidetes and Lactobacillus in the KI model ( $P<0.0001$ ). Helicobacter has been identified with many infectious diseases and was increased after HFD induction and inhibited after K. marxianus JLU-1016 and AR strain JLU-1016A treatments. The strain JLU-1016A exhibited better results possibly with acid-tolerance properties to pass through an acidic environment of the stomach. Conclusions. K. marxianus may have a beneficial effect on KI by improving gut microbiota and inhibiting TLR4/NF-κB pathway activation.

The Effect of Super-Repressor IkB-Loaded Exosomes (Exo-srIκBs) in Chronic Post-Ischemia Pain (CPIP) Models

Complex regional pain syndrome (CRPS) is a condition associated with neuropathic pain that causes significant impairment of daily activities and functioning. Nuclear factor kappa B (NFκB) is thought to play an important role in the mechanism of CRPS. Recently, exosomes loaded with super-repressor inhibitory kappa B (Exo-srIκB, IκB; inhibitor of NFκB) have been shown to have potential anti-inflammatory effects in various inflammatory disease models. We investigated the therapeutic effect of Exo-srIκB on a rodent model with chronic post-ischemia pain (CPIP), a representative animal model of Type I CRPS. After intraperitoneal injection of a vehicle, Exo-srIκB, and pregabalin, the paw withdrawal threshold (PWT) was evaluated up to 48 h. Administration of Exo-srIκB increased PWT compared to the vehicle and pregabalin, and the relative densities of p-IκB and IκB showed significant changes compared to the vehicle 24 h after Exo-srIκB injection. The levels of several cytokines and chemokines were reduced by the administration of Exo-srIκB in mice with CPIP. In conclusion, our results showed more specifically the role of NFκB in the pathogenesis of CRPS and provided a theoretical background for novel treatment options for CRPS.

Therapeutic effects of traditional Chinese medicine on gouty nephropathy: Based on NF-κB signalingpathways

As the final product of purine metabolism, excess serum uric acid (SUA) aggravates the process of some metabolic diseases. SUA causes renal tubule damage, interstitial fibrosis, and glomerular hardening, leading to gouty nephropathy (GN). A growing number of investigations have shown that NF-κB mediated inflammation and oxidative stress have been directly involved in the pathogenesis of GN. Traditional Chinese medicine's treatment methods of GN have amassed a wealth of treatment experience. In this review, we first describe the mechanism of NF-κB signaling pathways in GN. Subsequently, we highlight traditional Chinese medicine that can treat GN through NF-κB pathways. Finally, commenting on promising candidate targets of herbal medicine for GN treatment via suppressing NF-κB signaling pathways was summarized.

The Therapeutic Potential and Clinical Significance of Exosomes as Carriers of Drug Delivery System

Drug delivery system (DDS) realizes the drug delivery process through the drug carrier. As an important part of DDS, the selection of the drug carrier material is extremely critical, which requires the carrier material to possess excellent biocompatibility and targeting and not affect the pharmacological action of the drug. As one of the endogenous extracellular vesicles, exosomes are 30-100 nm in diameter, which are considered a new generation of a natural nanoscale delivery system. Exosomes secreted by different types of cells carry signaling molecules (such as proteins and nucleic acid) playing an important role in cell behaviors. Owing to their ability to specialize in intercellular communication, exosomes provide a distinctive method to deliver therapeutic drugs to target cells. In this concept, exosomes as the natural liposomes carry endogenous biomolecules, have excellent biocompatibility, and could be loaded with cargo both in vivo and in vitro. In addition, modifications by genetic and/or chemical engineering to part of the exosome surface or complement the desired natural effect may enhance the targeting with drug loading capability. Notably, exosomes weakly react with serum proteins prolonging cargo half-life. Overall, exosomes as natural carriers integrate the superiority of synthetic nanocarriers and cellular communication while precluding their limitations, which provides novel and reliable methods for drug delivery and treatment. Our review focuses on the therapeutic potentials and clinical values of exosomes as a carrier of drug delivery system in multiple diseases, including cancer, nervous, immune, and skeletal system diseases.

Oroxylin A ameliorates AKI-to-CKD transition through maintaining PPARα-BNIP3 signaling-mediated mitochondrial homeostasis

Background: Acute kidney injury (AKI) occurs in approximately 7–18% of all hospitalizations, but there are currently no effective drug therapy for preventing AKI or delaying its progression to chronic kidney disease (CKD). Recent studies have shown that Scutellaria baicalensis, a traditional Chinese herb, could attenuate cisplatin-induced AKI, although the mechanism remains elusive. Further, it is unknown whether its major active component, Oroxylin A (OA), can alleviate kidney injury.

Methods: The therapeutic effect of OA was evaluated by using ischemia-reperfusion (IR) and cisplatin mediated-AKI mice and HK-2 cells under hypoxia-reoxygenation (HR) conditions. HE staining, transmission electron microscopy, flow cytometry, immunofluorescence, qPCR, Western blot, PPARα inhibitor, BNIP3 siRNA and ChIP assay were used to explore the role and mechanism of OA in AKI.

Results: OA ameliorated tubular damage and dramatically decreased serum creatinine (Scr) and urea nitrogen (BUN), and the expressions of renal injury markers (Kim-1, Ngal) in AKI mice induced by both IR injury and cisplatin, as well as attenuating AKI-to-CKD transition. In vitro experiments showed that OA alleviated HR-induced mitochondrial homeostasis imbalance in renal tubular epithelial cells. Mechanistically, OA dose-dependently induced the expression of Bcl-2/adenovirus E1B 19-kDa interacting protein (BNIP3), while knockdown of BNIP3 expression reversed the protection of OA against HR-mediated mitochondrial injury. Network pharmacological analysis and experimental validation suggested that OA enhanced BNIP3 expression via upregulating the expression of peroxisome proliferator activated receptor alpha (PPARα), which induced the transcription of BNIP3 via directly binding to its promoter region. Both in vitro and in vivo experiments confirmed that the renoprotective effect of OA was dramatically reduced by GW6471, a PPARα antagonist.

Conclusion: Our findings revealed that OA ameliorates AKI-to-CKD transition by maintaining mitochondrial homeostasis through inducing PPARα-BNIP3 signaling pathway, indicating that OA may serve as a candidate therapeutic strategy for alleviating AKI and CKD.

Bioengineering exosomes for treatment of organ ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury is a leading cause of death worldwide. It arises from blood reflowing after tissue hypoxia induced by ischemia that causes severe damages due to the accumulation of reactive oxygen species and the activation of inflammatory responses. Exosomes are the smallest members of the extracellular vesicles' family, which originate from nearly all eukaryotic cells. Exosomes have a great potential in the treatment of I/R injury either in native or modified forms. Native exosomes are secreted by different cell types, such as stem cells, and contain components such as specific miRNA molecules with tissue protective properties. On the other hand, exosome bioengineering has recently received increased attention in context of current advances in the purification, manipulation, biological characterization, and pharmacological applications. There are various pre-isolation and post-isolation manipulation approaches that can be utilized to increase the circulation half-life of exosomes or the availability of their bioactive cargos in the target site. In this review, the various therapeutic actions of native exosomes in different I/R injury will be discussed first. Exosome bioengineering approaches will then be explained, including pre- and post-isolation manipulation methods, applicability for delivery of bioactive agents to injured tissue, clinical translation issues, and future perspectives.

Extracellular vesicles for renal therapeutics: State of the art and future perspective

With the ever-increasing burden of kidney disease, the need for developing new therapeutics to manage this disease has never been greater. Extracellular vesicles (EVs) are natural membranous nanoparticles present in virtually all organisms. Given their excellent delivery capacity in the body, EVs have emerged as a frontier technology for drug delivery and have the potential to usher in a new era of nanomedicine for kidney disease. This review is focused on why EVs are such compelling drug carriers and how to release their fullest potentiality in renal therapeutics. We discuss the unique features of EVs compared to artificial nanoparticles and outline the engineering technologies and steps in developing EV-based therapeutics, with an emphasis on the emerging approaches to target renal cells and prolong kidney retention. We also explore the applications of EVs as natural therapeutics or as drug carriers in the treatment of renal disorders and present our views on the critical challenges in manufacturing EVs as next-generation renal therapeutics.

Quantitative Biodistribution and Pharmacokinetics Study of GMP-Grade Exosomes Labeled with 89Zr Radioisotope in Mice and Rats

For the successful clinical advancement of exosome therapeutics, the biodistribution and pharmacokinetic profile of exogenous exosomes in various animal models must be determined. Compared with fluorescence or bioluminescence imaging, radionuclide imaging confers multiple advantages for the in vivo tracking of biomolecular therapeutics because of its excellent sensitivity for deep tissue imaging and potential for quantitative measurement. Herein, we assessed the quantitative biodistribution and pharmacokinetics of good manufacturing practice-grade therapeutic exosomes labeled with zirconium-89 (⁸⁹Zr) after systemic intravenous administration in mice and rats. Quantitative biodistribution analysis by positron emission tomography/computed tomography and gamma counting in mice and rats revealed that the total ⁸⁹Zr signals in the organs were lower in rats than in mice, suggesting a higher excretion rate of exosomes in rats. A prolonged ⁸⁹Zr signal for up to 7 days in most organs indicated that substantial amounts of exosomes were taken up by the parenchymal cells in those organs, highlighting the therapeutic potential of exosomes for the intracellular delivery of therapeutics. Exosomes were mainly distributed in the liver and to a lesser extent in the spleen, while a moderately distributed in the kidney, lung, stomach, intestine, urinary bladder, brain, and heart. Exosomes were rapidly cleared from the blood circulation, with a rate greater than that of free ⁸⁹Zr, indicating that exosomes might be rapidly taken up by cells and tissues.

Hyper-inflammatory responses in COVID-19 and anti-inflammatory therapeutic approaches

The coronavirus disease 2019 (COVID-19) is an ongoing global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Patients with severe COVID-19 exhibit hyper-inflammatory responses characterized by excessive activation of myeloid cells, including monocytes, macrophages, and neutrophils, and a plethora of pro-inflammatory cytokines and chemokines. Accumulating evidence also indicates that hyper-inflammation is a driving factor for severe progression of the disease, which has prompted the development of anti-inflammatory therapies for the treatment of patients with COVID-19. Corticosteroids, IL-6R inhibitors, and JAK inhibitors have demonstrated promising results in treating patients with severe disease. In addition, diverse forms of exosomes that exert anti-inflammatory functions have been tested experimentally for the treatment of COVID-19. Here, we briefly describe the immunological mechanisms of the hyper-inflammatory responses in patients with severe COVID-19. We also summarize current anti-inflammatory therapies for the treatment of severe COVID-19 and novel exosome-based therapeutics that are in experimental stages.

Extracellular vesicles in kidney transplantation: a state-of-the-art review

Kidney transplantation is the optimal treatment for patients with kidney failure; however, early detection and timely treatment of graft injury remain a challenge. Precise and noninvasive techniques of graft assessment and innovative therapeutics are required to improve kidney transplantation outcomes. Extracellular vesicles (EVs) are lipid bilayer-delimited particles with unique biosignatures and immunomodulatory potential, functioning as intermediaries of cell signalling. Promising evidence exists for the potential of EVs to develop precision diagnostics of graft dysfunction, and prognostic biomarkers for clinician decision making. The inherent targeting characteristics of EVs and their low immunogenic and toxicity profiles combined with their potential as vehicles for drug delivery make them ideal targets for development of therapeutics to improve kidney transplant outcomes. In this review, we summarize the current evidence for EVs in kidney transplantation, discuss common methodological principles of EV isolation and characterization, explore upcoming innovative approaches in EV research, and discuss challenges and opportunities to enable translation of research findings into clinical practice.

EXPLORing exosomes for the treatment of acute kidney injury

Exosomes are emerging as a novel drug delivery system for the treatment of numerous diseases, including acute kidney injury. In this issue of Kidney International, Kim et al. use a novel optogenetically engineered exosome technology, "EXPLOR," to deliver the exosomal repressor of nuclear factor-κB into mice before and after renal ischemia-reperfusion. They report that these exosomes downregulated renal nuclear factor-κB signaling and ameliorated acute kidney injury. This study deserves attention for its significant scientific and potential clinical value in acute kidney injury.

Biodistribution of Exosomes and Engineering Strategies for Targeted Delivery of Therapeutic Exosomes

Exosomes are cell-secreted nano-sized vesicles which deliver diverse biological molecules for intercellular communication. Due to their therapeutic potential, exosomes have been engineered in numerous ways for efficient delivery of active pharmaceutical ingredients to various target organs, tissues, and cells. In vivo administered exosomes are normally delivered to the liver, spleen, kidney, lung, and gastrointestinal tract and show rapid clearance from the blood circulation after systemic injection. The biodistribution and pharmacokinetics (PK) of exosomes can be modulated by engineering various factors such as cellular origin and membrane protein composition of exosomes. Recent advances accentuate the potential of targeted delivery of engineered exosomes even to the most challenging organs including the central nervous system. Major breakthroughs have been made related to various imaging techniques for monitoring in vivo biodistribution and PK of exosomes, as well as exosomal surface engineering technologies for inducing targetability. For inducing targeted delivery, therapeutic exosomes can be engineered to express various targeting moieties via direct modification methods such as chemically modifying exosomal surfaces with covalent/non-covalent bonds, or via indirect modification methods by genetically engineering exosome-producing cells. In this review, we describe the current knowledge of biodistribution and PK of exosomes, factors determining the targetability and organotropism of exosomes, and imaging technologies to monitor in vivo administered exosomes. In addition, we highlight recent advances in strategies for inducing targeted delivery of exosomes to specific organs and cells.