Macrophage M2 polarization induced by exosomes from adipose-derived stem cells contributes to the exosomal proangiogenic effect on mouse ischemic hindlimb

Exosomes from Hypoxia Preconditioned Muscle-Derived Stem Cells Enhance Cell-Free Corpus Cavernosa Angiogenesis and Reproductive Function Recovery

Tissue engineering for penile corpora cavernosa defects requires microvascular system reconstruction.GelMA hydrogels show promise for tissue regeneration. However, using stem cells faces challenges such as immune rejection, limited proliferation and differentiation, and biosafety concerns. Therefore, acellular tissue regeneration may avoid these issues. Exosomes are used from muscle-derived stem cells (MDSCs) to modify 3D-printed hydrogel scaffolds for acellular tissue regeneration. Hypoxia-preconditioned MDSC-derived exosomes are obtained to enhance the therapeutic effect. In contrast to normoxic exosomes (N-Exos), hypoxic exosomes (H-Exos) are found to markedly enhance the proliferation, migration, and capillary-like tube formation of human umbilical vein endothelial cells (HUVECs). High-throughput sequencing analysis of miRNAs isolated from both N-Exos and H-Exos revealed a significant upregulation of miR-21-5p in H-Exos following hypoxic preconditioning. Further validation demonstrated that the miR-21-5p/PDCD4 pathway promoted the proliferation of HUVECs. Epigallocatechin gallate (EGCG) is introduced to improve the mechanical properties and biocompatibility of GelMA hydrogels. EGCG-GelMA scaffolds loaded with different types of Exos are transplanted to repair rabbit penile corpora cavernosa defects, observed the blood flow and repair status of the defect site through color Doppler ultrasound and magnetic resonance imaging, and ultimately restored the rabbit penile erection function and successfully bred offspring. Thus, acellular hydrogel scaffolds offer an effective treatment for penile corpora cavernosa defects.

Effects of spinal cord injury associated exosomes delivered tRF-41 on the progression of spinal cord injury progression

BACKGROUND

Spinal cord injury (SCI) is a devastating neurological and pathological condition. Exosomal tsRNAs have reported to be promising biomarkers for cancer diagnosis and therapy. This study aimed to investigate the roles of SCI-associated exosomes, and related tsRNA mechanisms in SCI.

METHODS

The serum of healthy controls and SCI patients at the acute stage were collected for exosomes isolation, and the two different exosomes were used to treat human astrocytes (HA). The cell viability, apoptosis, and cycle were determined, and the expression of the related proteins were detected by western blot. Then, the two different exosomes were sent for tsRNA sequencing, and four significant known differentially expressed tsRNAs (DE-tsRNAs) were selected for RT-qPCR validation. Finally, tRT-41 was chosen to further explore its roles and related mechanisms in SCI.

RESULTS

After sequencing, 21 DE-tsRNAs were identified, which were significantly enriched in pathways of Apelin, AMPK, Hippo, MAPK, Ras, calcium, PI3K-Akt, and Rap1. RT-qPCR showed that tRF-41 had higher levels in the SCI-associated exosomes. Compared with the control HA, healthy exosomes did not significantly affect the growth of HA cells, but SCI-associated exosomes inhibited viability of HA cells, while promoted their apoptosis and increased the HA cells in G2/M phase; but tRF-41 inhibitor reversed the actions of SCI-associated exosomes. Additionally, SCI-associated exosomes, similar with tRF-41 mimics, down-regulated IGF-1, NGF, Wnt3a, and β-catenin, while up-regulated IL-1β and IL-6; but tRF-41 inhibitor had the opposite actions, and reversed the effects induced by SCI-associated exosomes.

CONCLUSIONS

SCI-associated exosomes delivered tRF-41 may inhibit the growth of HA through regulating Wnt/ β-catenin pathway and inflammation response, thereby facilitating the progression of SCI.

Recent advances in the use of extracellular vesicles from adipose-derived stem cells for regenerative medical therapeutics

Adipose-derived stem cells (ADSCs) are a subset of mesenchymal stem cells (MSCs) isolated from adipose tissue. They possess remarkable properties, including multipotency, self-renewal, and easy clinical availability. ADSCs are also capable of promoting tissue regeneration through the secretion of various cytokines, factors, and extracellular vesicles (EVs). ADSC-derived EVs (ADSC-EVs) act as intercellular signaling mediators that encapsulate a range of biomolecules. These EVs have been found to mediate the therapeutic activities of donor cells by promoting the proliferation and migration of effector cells, facilitating angiogenesis, modulating immunity, and performing other specific functions in different tissues. Compared to the donor cells themselves, ADSC-EVs offer advantages such as fewer safety concerns and more convenient transportation and storage for clinical application. As a result, these EVs have received significant attention as cell-free therapeutic agents with potential future application in regenerative medicine. In this review, we focus on recent research progress regarding regenerative medical use of ADSC-EVs across various medical conditions, including wound healing, chronic limb ischemia, angiogenesis, myocardial infarction, diabetic nephropathy, fat graft survival, bone regeneration, cartilage regeneration, tendinopathy and tendon healing, peripheral nerve regeneration, and acute lung injury, among others. We also discuss the underlying mechanisms responsible for inducing these therapeutic effects. We believe that deciphering the biological properties, therapeutic effects, and underlying mechanisms associated with ADSC-EVs will provide a foundation for developing a novel therapeutic approach in regenerative medicine.

Exosomes-carried curcumin based on polysaccharide hydrogel promote flap survival

Flap grafting is a common technique used to repair skin defects in orthopedics and plastic and reconstructive surgeries. However, oxidative stress injury caused by ischemia and ischemia-reperfusion injury at the distal end of the skin flap can cause flap necrosis. Curcumin is a natural compound with anti-inflammatory and antioxidant properties that tackle oxidative stress. However, its applicability is limited by its poor water solubility. Exosomes are membranous vesicles that can be loaded with hydrophobic drugs. They are widely studied in drug delivery applications and can be investigated to augment curcumin efficiency. In this study, a self-healing oxidized pullulan polysaccharide-carboxymethylated chitosan composite hydrogel was used as a curcumin-loaded exosome delivery system to evaluate its impact on the viability of skin flaps. The hydrogel exhibited good self-healing properties that allowed the continuous and stable release of drugs. It had anti-inflammatory and antioxidant properties that could reduce oxidative stress damage due to early ischemia and hypoxia of the skin flap in vitro. Moreover, this composite hydrogel attenuated inflammatory responses, promoted angiogenesis, and reduced the distal necrosis of the flap in vivo. Therefore, our hydrogel provides a novel strategy for skin flap graft protection with reduced necrosis and the potential for broad clinical applications.

Mechanical stretch preconditioned adipose-derived stem cells elicit polarization of anti-inflammatory M2-like macrophages and improve chronic wound healing

Transplantation of adipose-derived stem cells (ASCs) is a promising option in the field of chronic wounds treatment. However, the effectiveness of ASCs therapies has been hampered by highly inflammatory environment in chronic wound areas. These problems could be partially circumvented using efficient approaches that boost the survival and anti-inflammatory capacity of transplanted ASCs. Here, by application of mechanical stretch (MS), we show that ASCs exhibits increased survival and immunoregulatory properties in vitro. MS triggers the secretion of macrophage colony stimulating factor (M-CSF) from ASCs, a chemokine that is linked to anti-inflammatory M2-like macrophages polarization. When the MS-ASCs were transplanted to chronic wounds, the wound area yields significantly faster closure rate and lower inflammatory mediators, largely due to macrophages polarization driven by transplanted MS-ASCs. Thus, our work shows that mechanical stretch can be harnessed to enhance ASCs transplantation efficiency in chronic wounds treatment.

Colony-stimulating factor-1 receptor inhibition combined with paclitaxel exerts effective antitumor effects in the treatment of ovarian cancer

Ovarian cancer is the tumor with the highest mortality among gynecological malignancies. Studies have confirmed that paclitaxel chemoresistance is associated with increased infiltration of tumor-associated macrophages (TAMs) in the microenvironment. Colony-stimulating factor 1 (CSF-1) receptor (CSF-1R) plays a key role in regulating the number and differentiation of macrophages in certain solid tumors. There are few reports on the effects of targeted inhibition of CSF-1R in combination with chemotherapy on ovarian cancer and the tumor microenvironment. Here, we explored the antitumor efficacy and possible mechanisms of the CSF - 1R inhibitor pexidartinib (PLX3397) when combined with the first-line chemotherapeutic agent paclitaxel in the treatment of ovarian cancer. We found that CSF-1R is highly expressed in ovarian cancer cells and correlates with poor prognosis. Treatment by PLX3397 in combination with paclitaxel significantly inhibited the growth of ovarian cancer both in vitro and in vivo. Blockade of CSF-1R altered the macrophage phenotype and reprogrammed the immunosuppressive cell population in the tumor microenvironment.

A whole-course-repair system based on ROS/glucose stimuli-responsive EGCG release and tunable mechanical property for efficient treatment of chronic periodontitis in diabetic rats

Elevated glucose levels, multiple pro-inflammatory cytokines and the generation of excessive reactive oxygen species (ROS) are pivotal characteristics within the microenvironments of chronic periodontitis with diabetes mellitus (CPDM). Control of inflammation and modulation of immune system are required in the initial phase of CPDM treatment, while late severe periodontitis requires a suitable scaffold to promote osteogenesis, rebuild periodontal tissue and reduce alveolar bone resorption. Herein, a whole-course-repair system is introduced by an injectable hydrogel using phenylboronic acid functionalized oxidized sodium alginate (OSA-PBA) and carboxymethyl chitosan (CMC). Epigallocatechin-3-gallate (EGCG) was loaded to simultaneously adjust the mechanical property of the OSA-PBA/CMC + EGCG hydrogel (OPCE). This hydrogel has distinctive adaptability, injectability, and ROS/glucose-triggered release of EGCG, making it an ideal drug delivery carrier. As expected, OPCE hydrogel shows favourable antioxidant and anti-inflammatory properties, along with a regulatory influence on the phenotypic transition of macrophages, providing a favourable immune microenvironment. Apart from that, it provides a favourable mechanical support for osteoblast/osteoclast differentiation regulation at the late proliferation stage of periodontal regeneration. The practical therapeutic effects of OPCE hydrogels were also confirmed when applied for treating periodontitis in diabetic rats. In summary, OPCE hydrogel may be a promising whole-course-repair system for the treatment of CPDM.

Journey into tomorrow: cardiovascular wellbeing transformed by nano-scale innovations

Worldwide, cardiovascular diseases (CVDs) account for the vast majority of deaths and place enormous financial strains on healthcare systems. Gold nanoparticles, quantum dots, polymeric nanoparticles, carbon nanotubes, and lipids are innovative nanomaterials promising in tackling CVDs. In the setting of CVDs, these nanomaterials actively impact cellular responses due to their distinctive properties, including surface energy and topographies. Opportunities to more precisely target CVDs have arisen due to recent developments in nanomaterial science, which have introduced fresh approaches. An in-depth familiarity with the illness and its targeted mechanisms is necessary to use nanomaterials in CVDs effectively. We support the academic community's efforts to prioritize Nano-technological techniques in addressing risk factors linked with cardiovascular diseases, acknowledging the far-reaching effects of these conditions. The significant impact of nanotechnology on the early detection and treatment of cardiovascular diseases highlights the critical need for novel approaches to this pressing health problem, which is affecting people worldwide.

Engineering M2-type macrophages with a metal polyphenol network for peripheral artery disease treatment

Functional cell treatment for critical limb ischemia is limited by cell viability loss and dysfunction resulting from a harmful ischemic microenvironment. Metal-polyphenol networks have emerged as novel cell delivery vehicles for protecting cells from the detrimental ischemic microenvironment and prolonging the survival rate of cells in the ischemic microenvironment. M2 macrophages are closely related to tissue repair, and they secrete anti-inflammatory factors that contribute to lesion repair. However, these cells are easily metabolized in the body with low efficiency. Herein, M2 macrophages were decorated with a metal‒polyphenol network that contains copper ions and epigallocatechin gallate (Cu-EGCG@M2) to increase cell survival and therapeutic potential. Cu-EGCG@M2 synergistically promoted angiogenesis through the inherent angiogenesis effect of M2 macrophages and copper ions. We found that Cu-EGCG@M2 increased in vitro viability and strengthened the in vivo therapeutic effect on the ischemic hindlimbs of mice, which promoted the recovery of blood and muscle regeneration, resulting in superior limb salvage. These therapeutic effects were ascribed to the increased survival rate and therapeutic period of M2 macrophages, as well as the ameliorated microenvironment at the ischemic site. Additionally, Cu-EGCG exhibited antioxidant, anti-inflammatory, and proangiogenic effects. Our findings provide a feasible option for cell-based treatment of CLI.

Zinc oxide nanoparticles exacerbate skin epithelial cell damage by upregulating pro-inflammatory cytokines and exosome secretion in M1 macrophages following UVB irradiation-induced skin injury

BACKGROUND

Zinc oxide nanoparticles (ZnONPs) are common materials used in skin-related cosmetics and sunscreen products due to their whitening and strong UV light absorption properties. Although the protective effects of ZnONPs against UV light in intact skin have been well demonstrated, the effects of using ZnONPs on damaged or sunburned skin are still unclear. In this study, we aimed to reveal the detailed underlying mechanisms related to keratinocytes and macrophages exposed to UVB and ZnONPs.

RESULTS

We demonstrated that ZnONPs exacerbated mouse skin damage after UVB exposure, followed by increased transepidermal water loss (TEWL) levels, cell death and epithelial thickness. In addition, ZnONPs could penetrate through the damaged epithelium, gain access to the dermis cells, and lead to severe inflammation by activation of M1 macrophage. Mechanistic studies indicated that co-exposure of keratinocytes to UVB and ZnONPs lysosomal impairment and autophagy dysfunction, which increased cell exosome release. However, these exosomes could be taken up by macrophages, which accelerated M1 macrophage polarization. Furthermore, ZnONPs also induced a lasting inflammatory response in M1 macrophages and affected epithelial cell repair by regulating the autophagy-mediated NLRP3 inflammasome and macrophage exosome secretion.

CONCLUSIONS

Our findings propose a new concept for ZnONP-induced skin toxicity mechanisms and the safety issue of ZnONPs application on vulnerable skin. The process involved an interplay of lysosomal impairment, autophagy-mediated NLRP3 inflammasome and macrophage exosome secretion. The current finding is valuable for evaluating the effects of ZnONPs for cosmetics applications.

Therapeutic potential of RNA-enriched extracellular vesicles: The next generation in RNA delivery via biogenic nanoparticles

Exosomes are extracellular vesicles (EVs) (∼50-150 nm) that have emerged as promising vehicles for therapeutic applications and drug delivery. These membrane-bound particles, released by all actively dividing cells, have the ability to transfer effector molecules, including proteins, RNA, and even DNA, from donor cells to recipient cells, thereby modulating cellular responses. RNA-based therapeutics, including microRNAs, messenger RNAs, long non-coding RNAs, and circular RNAs, hold great potential in controlling gene expression and treating a spectrum of medical conditions. RNAs encapsulated in EVs are protected from extracellular degradation, making them attractive for therapeutic applications. Understanding the intricate biology of cargo loading and transfer within EVs is pivotal to unlocking their therapeutic potential. This review discusses the biogenesis and classification of EVs, methods for loading RNA into EVs, their advantages as drug carriers over synthetic-lipid-based systems, and the potential applications in treating neurodegenerative diseases, cancer, and viral infections. Notably, EVs show promise in delivering RNA cargo across the blood-brain barrier and targeting tumor cells, offering a safe and effective approach to RNA-based therapy in these contexts.

Microenvironment Remodeling Self-Healing Hydrogel for Promoting Flap Survival

Random flap grafting is a routine procedure used in plastic and reconstructive surgery to repair and reconstruct large tissue defects. Flap necrosis is primarily caused by ischemia-reperfusion injury and inadequate blood supply to the distal flap. Ischemia-reperfusion injury leads to the production of excessive reactive oxygen species, creating a pathological microenvironment that impairs cellular function and angiogenesis. In this study, we developed a microenvironment remodeling self-healing hydrogel [laminarin-chitosan-based hydrogel-loaded extracellular vesicles and ceria nanozymes (LCH@EVs&CNZs)] to improve the flap microenvironment and synergistically promote flap regeneration and survival. The natural self-healing hydrogel (LCH) was created by the oxidation laminarin and carboxymethylated chitosan via a Schiff base reaction. We loaded this hydrogel with CNZs and EVs. CNZs are a class of nanomaterials with enzymatic activity known for their strong scavenging capacity for reactive oxygen species, thus alleviating oxidative stress. EVs are cell-secreted vesicular structures containing thousands of bioactive substances that can promote cell proliferation, migration, differentiation, and angiogenesis. The constructed LCH@EVs&CNZs demonstrated a robust capacity for scavenging excess reactive oxygen species, thereby conferring cellular protection in oxidative stress environments. Moreover, these constructs notably enhance cell migration and angiogenesis. Our results demonstrate that LCH@EVs&CNZs effectively remodel the pathological skin flap microenvironment and marked improve flap survival. This approach introduces a new therapeutic strategy combining microenvironmental remodeling with EV therapy, which holds promise for promoting flap survival.

M1 macrophage-derived exosome for reprograming M2 macrophages and combining endogenous NO gas therapy with enhanced photodynamic synergistic therapy in colorectal cancer

Reprogramming immunosuppressive M2 macrophages into M1 macrophages in tumor site provides a new strategy for the immunotherapy of colorectal cancer. In this study, M1 macrophage-derived exosome nanoprobe (M1UC) with Ce6-loaded upconversion material is designed to enhance the photodynamic performance of Ce6 while reprogramming M2 macrophages at tumor site and producing NO gas for three-mode synergistic therapy. Under the excitation of near-infrared light at 808 nm, the probe can generate 660 nm up-conversion fluorescence, which enables the photosensitizer Ce6 to produce ROS efficiently. In addition, the probe leads the production of NO by nitric oxide synthase on exosomes. Confocal laser and flow cytometry results show that M1UC probe reprograms M2 macrophages into M1 macrophages with an efficiency of 95.12%. The cell experiments show that the apoptosis rate of the three-mode synergistic therapy group is 78.8%, and the therapeutic effect is significantly higher than those of the other single treatment groups. In vivo experiments results show that M1UC probes maximally gather at the tumor site after 12 h of intravenous injection in orthotopic colorectal cancer mice. After 808 nm laser irradiation, the survival rate of mice is 100% and the recurrence rate was 0 within 60 d, and the therapeutic effect is significantly higher than those of other single treatment groups, which is also confirmed by immunohistochemistry. This M1 macrophage-derived exosome nanoplatform which is based on the three modes of immunotherapy, gas therapy and photodynamic therapy, provides a new design idea for the diagnosis and treatment of deep tumors.

Microglia-derived extracellular vesicles in homeostasis and demyelination/remyelination processes

Microglia (MG) play a crucial role as the predominant myeloid cells in the central nervous system and are commonly activated in multiple sclerosis. They perform essential functions under normal conditions, such as actively surveying the surrounding parenchyma, facilitating synaptic remodeling, engulfing dead cells and debris, and protecting the brain against infectious pathogens and harmful self-proteins. Extracellular vesicles (EVs) are diverse structures enclosed by a lipid bilayer that originate from intracellular endocytic trafficking or the plasma membrane. They are released by cells into the extracellular space and can be found in various bodily fluids. EVs have recently emerged as a communication mechanism between cells, enabling the transfer of functional proteins, lipids, different RNA species, and even fragments of DNA from donor cells. MG act as both source and recipient of EVs. Consequently, MG-derived EVs are involved in regulating synapse development and maintaining homeostasis. These EVs also directly influence astrocytes, significantly increasing the release of inflammatory cytokines like IL-1β, IL-6, and TNF-α, resulting in a robust inflammatory response. Furthermore, EVs derived from inflammatory MG have been found to inhibit remyelination, whereas Evs produced by pro-regenerative MG effectively promote myelin repair. This review aims to provide an overview of the current understanding of MG-derived Evs, their impact on neighboring cells, and the cellular microenvironment in normal conditions and pathological states, specifically focusing on demyelination and remyelination processes.

Engineered exosomes derived from stem cells: a new brain-targeted strategy

INTRODUCTION

Using engineered exosomes produced from stem cells is an experimental therapeutic approach for treating brain diseases. According to reports, preclinical research has demonstrated notable neurogenesis and angiogenesis effects using modified stem cell-derived exosomes. These biological nanoparticles have a variety of anti-apoptotic, anti-inflammatory, and antioxidant properties that make them very promising for treating nervous system disorders.

AREAS COVERED

This review examines different ways to enhance the delivery of modified stem cell-derived exosomes, how they infiltrate the blood-brain barrier (BBB), and how they facilitate their access to the brain. We would also like to determine whether these nanoparticles have the most significant transmission rates through BBB when targeting brain lesions.

EXPERT OPINION

Using engineered stem cell-derived exosomes for treating brain disorders has generated considerable attention toward clinical research and application. However, stem cell-derived exosomes lack consistency, and their mechanisms of action are uncertain. Therefore, upcoming research needs to prioritize examining the underlying mechanisms and strategies via which these nanoparticles combat neurological disorders.

Co-Delivery of Bioengineered Exosomes and Oxygen for Treating Critical Limb Ischemia in Diabetic Mice

Diabetic patients with critical limb ischemia face a high rate of limb amputation. Regeneration of the vasculature and skeletal muscles can salvage diseased limbs. Therapy using stem cell-derived exosomes that contain multiple proangiogenic and promyogenic factors represents a promising strategy. Yet the therapeutic efficacy is not optimal because exosomes alone cannot efficiently rescue and recruit endothelial and skeletal muscle cells and restore their functions under hyperglycemic and ischemic conditions. To address these limitations, we fabricated ischemic-limb-targeting stem cell-derived exosomes and oxygen-releasing nanoparticles and codelivered them in order to recruit endothelial and skeletal muscle cells, improve cell survival under ischemia before vasculature is established, and restore cell morphogenic function under high glucose and ischemic conditions. The exosomes and oxygen-releasing nanoparticles, delivered by intravenous injection, specifically accumulated in the ischemic limbs. Following 4 weeks of delivery, the exosomes and released oxygen synergistically stimulated angiogenesis and muscle regeneration without inducing substantial inflammation and reactive oxygen species overproduction. Our work demonstrates that codelivery of exosomes and oxygen is a promising treatment solution for saving diabetic ischemic limbs.

MiR-146b-5p enriched bioinspired exosomes derived from fucoidan-directed induction mesenchymal stem cells protect chondrocytes in osteoarthritis by targeting TRAF6

Osteoarthritis (OA) is a common degenerative joint disease characterized by progressive cartilage degradation and inflammation. In recent years, mesenchymal stem cells (MSCs) derived exosomes (MSCs-Exo) have attracted widespread attention for their potential role in modulating OA pathology. However, the unpredictable therapeutic effects of exosomes have been a significant barrier to their extensive clinical application. In this study, we investigated whether fucoidan-pretreated MSC-derived exosomes (F-MSCs-Exo) could better protect chondrocytes in osteoarthritic joints and elucidate its underlying mechanisms. In order to evaluate the role of F-MSCs-Exo in osteoarthritis, both in vitro and in vivo studies were conducted. MiRNA sequencing was employed to analyze MSCs-Exo and F-MSCs-Exo, enabling the identification of differentially expressed genes and the exploration of the underlying mechanisms behind the protective effects of F-MSCs-Exo in osteoarthritis. Compared to MSCs-Exo, F-MSCs-Exo demonstrated superior effectiveness in inhibiting inflammatory responses and extracellular matrix degradation in rat chondrocytes. Moreover, F-MSCs-Exo exhibited enhanced activation of autophagy in chondrocytes. MiRNA sequencing of both MSCs-Exo and F-MSCs-Exo revealed that miR-146b-5p emerged as a promising candidate mediator for the chondroprotective function of F-MSCs-Exo, with TRAF6 identified as its downstream target. In conclusion, our research results demonstrate that miR-146b-5p encapsulated in F-MSCs-Exo effectively inhibits TRAF6 activation, thereby suppressing inflammatory responses and extracellular matrix degradation, while promoting chondrocyte autophagy for the protection of osteoarthritic cartilage cells. Consequently, the development of a therapeutic approach combining fucoidan with MSC-derived exosomes provides a promising strategy for the clinical treatment of osteoarthritis.

Aging and Metabolic Reprogramming of Adipose-Derived Stem Cells Affect Molecular Mechanisms Related to Cardiovascular Diseases

We performed a systematic search of the PubMed database for English-language articles related to the function of adipose-derived stem cells in the pathogenesis of cardiovascular diseases. In preclinical models, adipose-derived stem cells protected arteries and the heart from oxidative stress and inflammation and preserved angiogenesis. However, clinical trials did not reiterate successful treatments with these cells in preclinical models. The low success in patients may be due to aging and metabolic reprogramming associated with the loss of proliferation capacity and increased senescence of stem cells, loss of mitochondrial function, increased oxidative stress and inflammation, and adipogenesis with increased lipid deposition associated with the low potential to induce endothelial cell function and angiogenesis, cardiomyocyte survival, and restore heart function. Then, we identify noncoding RNAs that may be mechanistically related to these dysfunctions of human adipose-derived stem cells. In particular, a decrease in let-7, miR-17-92, miR-21, miR-145, and miR-221 led to the loss of their function with obesity, type 2 diabetes, oxidative stress, and inflammation. An increase in miR-34a, miR-486-5p, and mir-24-3p contributed to the loss of function, with a noteworthy increase in miR-34a with age. In contrast, miR-146a and miR-210 may protect stem cells. However, a systematic analysis of other noncoding RNAs in human adipose-derived stem cells is warranted. Overall, this review gives insight into modes to improve the functionality of human adipose-derived stem cells.

Preparation and Characterization Evaluation of Poly(L-Glutamic Acid)-g-Methoxy Poly(Ethylene Glycol)/Combretastatin A4/BLZ945 Nanoparticles for Cervical Cancer Therapy

Purpose

Cervical cancer (CC) is a highly vascularized tumor with abundant abnormal blood vessel, which could be targeted by therapeutic strategies. Poly(L-glutamic acid)-g-methoxy poly(ethylene glycol)/combretastatin A4 (CA4)/BLZ945 nanoparticles (CB-NPs) have shown great potential as nano vascular disrupting agents (VDAs) in the realm of synergistic cancer therapy.

Methods

In this study, we investigated the nanocharacteristics of CB-NPs, focusing on active pharmaceutical ingredients (API), as well as lyophilized samples combining API with protective agents (PAs). The in vivo efficacy of final sample (API + PAs) was evaluated.

Results

The assembled sphere of API with complex core and thin-shell structure was confirmed. PAs were found to significantly influence in vivo efficacy. Collaborative efforts between API and PAs, namely mannitol and lactose, resulted in the most promising lyophilized sample, ie, the final sample (FS2) for CC therapy. Impressively, FS2 demonstrated an exceptional 100% cure rate on the CC U14-bearing mice model.

Conclusion

FS2 has provided significant insights for cervical cancer therapy. It is also crucial to develop a comprehensive evaluation strategy for the formulation of nanomedicine, which has the potential to serve as a guideline for future clinical trials.

The Notch signaling-regulated angiogenesis in rheumatoid arthritis: pathogenic mechanisms and therapeutic potentials

Angiogenesis plays a key role in the pathological process of inflammation and invasion of the synovium, and primarily drives the progression of rheumatoid arthritis (RA). Recent studies have demonstrated that the Notch signaling may represent a new therapeutic target of RA. Although the Notch signaling has been implicated in the M1 polarization of macrophages and the differentiation of lymphocytes, little is known about its role in angiogenesis in RA. In this review, we discourse the unique roles of stromal cells and adipokines in the angiogenic progression of RA, and investigate how epigenetic regulation of the Notch signaling influences angiogenesis in RA. We also discuss the interaction of the Notch-HIF signaling in RA's angiogenesis and the potential strategies targeting the Notch signaling to improve the treatment outcomes of RA. Taken together, we further suggest new insights into future research regarding the challenges in the therapeutic strategies of RA.

Multifunctional polysaccharide composited microneedle for oral ulcers healing

Oral ulcers have periodicity and recurrence, and the etiology and causative mechanisms remain unclear; therefore, it is difficult to treat oral ulcers effectively. Current clinical treatment methods mainly include pain relief and administration of anti-inflammatories to prevent secondary infections and a prolonged recurrence cycle. However, these traditional treatment methods are administered independently and are susceptible to muscle movements and constant salivary secretion in the mouth, resulting in ineffective drug functioning. Therefore, development of a novel treatment to reduce wound infection and accelerate wound healing for oral ulcers is required for effective treatment. Herein, we report a multifunctional polysaccharide composite microneedle patch based on hyaluronic acid (HA) and hydroxypropyl trimethyl ammonium chloride chitosan (HACC) loaded with dexamethasone (DXMS) and basic fibroblast growth factor (bFGF) for oral ulcer healing. DXMS and bFGF encapsulated the HA tip portion of the microneedle patch, endowing the microneedle patches with anti-inflammatory and angiogenic properties. HACC was applied to the back of the microneedle patch, adding antibacterial properties. The experimental results indicated that the prepared dressings exhibited good antibacterial activity and effectively promoted cell migration growth and angiogenesis. More importantly, animal experiments have shown that multifunctional microneedle patches can effectively promote oral ulcer healing. Thus, these novel multifunctional polysaccharide composite microneedle patches have great potential for oral ulcers treatment.

Exploratory study of macrophage polarization and spatial distribution in colorectal cancer liver metastasis: a pilot study

Background

The liver is the most typical site of metastatic disease for patients with colorectal cancer (CRC), and up to half the patients with CRC will develop colorectal liver metastasis (CLM). Studying the tumor microenvironment, particularly macrophages and their spatial distribution, can give us critical insight into treatment.

Methods

Ten CLMs (five treatment-naïve and five post-neoadjuvant chemotherapy) were stained with multiplex immunofluorescence panels against cytokeratins, CD68, Arg1, CD206, CD86, CD163, PD-L1, and MRP8-14. Densities of cell phenotypes and their spatial distribution in the tumor center and the normal liver-tumor interface were correlated with clinicopathological variables.

Results

M2 macrophages were the predominant subtype in both the tumor center and the periphery, with a relatively higher density at the periphery. The larger tumors, more than 3.9 cm, were associated with higher densities of total CD68+ macrophages and CD68+CD163+ CD206neg and CD68+CD206+ CD163neg M2 macrophage subtypes. Total macrophages in the tumor periphery demonstrated significantly greater proximity to malignant cells than did those in the tumor center (p=0.0371). The presence of higher than median CD68+MRP8-14+CD86neg M1 macrophages in the tumor center was associated with poor overall survival (median 2.34 years) compared to cases with lower than median M1 macrophages at the tumor center (median 6.41 years) in univariate analysis.

Conclusion

The dominant polarization of the M2 macrophage subtype could drive new therapeutic approaches in CLM patients.

CX3CR1 regulates the development of renal interstitial fibrosis through macrophage polarization

OBJECTIVES

The binding of CX3C chemokine receptor 1 (CX3CR1) and its unique ligand CX3C chemokine ligand 1 (CX3CL1) can promote the migration of inflammatory cells to the lesion and affect the progression of renal interstitial fibrosis, but the underlying mechanisms remain unclear. This study aims to investigate whether CX3CR1 affects renal interstitial fibrosis by macrophage polarization.

METHODS

A mouse model of renal interstitial fibrosis was established by unilateral ureteral obstruction (UUO). C57/B6 mice were divided into a CX3CR1 inhibitor group (injected with CX3CR1 inhibitor AZD8797) and a model group (injected with physiological saline). After continuous intraperitoneal injection for 5 days, the ligated lateral kidneys of mice were obtained on the 7th day. Hematoxylin and eosin (HE) staining and Masson staining were used to observe the infiltration of inflammatory cells and the collagen fiber deposition in renal interstitium, respectively. The mRNA and protein expressions of CX3CR1, alpha-smooth muscle actin (α-SMA) and fibronectin (FN) in the kidneys were detected by reverse transcription PCR (RT-PCR) and Western blotting, respectively. Differentially expressed genes in kidney of the 2 groups were identified by whole genome sequencing and the differential expression of arginase-1 (Arg-1) was verified by RT-PCR. Flow cytometry was used to detect the proportion of M2 type macrophages in kidneys of the 2 groups.

RESULTS

The infiltration of inflammatory cells and the collagen fiber deposition in renal interstitium were significantly reduced in the CX3CR1 inhibitor group. The mRNA and protein levels of CX3CR1 and the mRNA levels of α-SMA and FN in the CX3CR1 inhibitor group were significantly lower than those of the model group (all P<0.05). Whole genome sequencing showed that the top 5 differentially expressed genes in kidney of the 2 groups were Ugt1a6b, Serpina1c, Arg-1, Retnla, and Nup62. RT-PCR verified that the expression level of Arg-1 in kidney of the CX3CR1 inhibitor group was significantly higher than that of the model group (P<0.001). Flow cytometry showed that the proportion of Arg1+CD206+M2 macrophages in kidney of the CX3CR1 inhibitor group was significantly higher than that of the model group (P<0.01).

CONCLUSIONS

Inhibiting CX3CR1 can effectively prevent the progression of renal interstitial fibrosis. The mechanism may be related to macrophage polarization towards M2 type and upregulation of Arg-1 expression.

Efferocytosis: An Emerging Therapeutic Strategy for Type 2 Diabetes Mellitus and Diabetes Complications

Increasing evidence indicates that chronic, low-grade inflammation is a significant contributor to the fundamental pathogenesis of type 2 diabetes mellitus (T2DM). Efferocytosis, an effective way to eliminate apoptotic cells (ACs), plays a critical role in inflammation resolution. Massive accumulation of ACs and the proliferation of persistent inflammation caused by defective efferocytosis have been proven to be closely associated with pancreatic islet β cell destruction, adipose tissue inflammation, skeletal muscle dysfunction, and liver metabolism abnormalities, which together are considered the most fundamental pathological mechanism underlying T2DM. Therefore, here we outline the association between the molecular mechanisms of efferocytosis in glucose homeostasis, T2DM, and its complications, and we analyzed the present constraints and potential future prospects for therapeutic targets in T2DM and its complications.

Knockdown of PTEN promotes colon cancer progression and induces M2 macrophage polarization in the colon cancer cell environment

Objective

This article aims to study the effect of phosphate and tension homolog deleted on chromosome ten (PTEN) knockdown on colon cancer progression and macrophage polarization in the cancer environment.

Materials and Methods and Results

The expression of PTEN in colon cancer tissues and colon cancer cells was significantly lower than in precancerous tissues or CCD-18Co cells, and the decrease was most evident in SW620 cells. The expressions of phosphate (p)-p38, c-Jun N-terminal kinase (JNK), activator protein 1 (AP-1), B-cell lymphoma-2 (Bcl-2) protein in colon cancer tissues and cells were significantly higher than in precancerous tissues or CCD-18Co cells (P-values < 0.05). Bcl-2-associated X (Bax) and Caspase-3 expressions in colon cancer tissues and cells were significantly lower than in precancerous tissues or CCD-18Co cells (P-values < 0.05). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was applied to measure cell viability. Transwell evaluated the cell migration and invasion ability. Si-PTEN improved the proliferation, migration, and invasion of SW620 cells (P-values < 0.05). The expression levels of arginase-1 (Arg-1), CD163, CD206 in colon cancer tissues were significantly higher than in precancerous tissues (P-values < 0.05). The cell cycle, the number of M1 and M2 double-positive cells were assessed by flow cytometry. Si-PTEN reduced the expression of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and inducible nitric oxide synthase (iNOS), which upregulated the expression of Arg-1, CD206, CD163, p-p38, JNK, and AP-1 (P-values < 0.05).

Conclusion

Si-PTEN promoted colon cancer progression and induced the polarization of M2 tumor-associated macrophages in the colon cancer cell environment.

Potential regulatory effects of stem cell exosomes on inflammatory response in ischemic stroke treatment

The high incidence and disability rates of stroke pose a heavy burden on society. Inflammation is a significant pathological reaction that occurs after an ischemic stroke. Currently, therapeutic methods, except for intravenous thrombolysis and vascular thrombectomy, have limited time windows. Mesenchymal stem cells (MSCs) can migrate, differentiate, and inhibit inflammatory immune responses. Exosomes (Exos), which are secretory vesicles, have the characteristics of the cells from which they are derived, making them attractive targets for research in recent years. MSC-derived exosomes can attenuate the inflammatory response caused by cerebral stroke by modulating damage-associated molecular patterns. In this review, research on the inflammatory response mechanisms associated with Exos therapy after an ischemic injury is discussed to provide a new approach to clinical treatment.

Exosomes in brain diseases: Pathogenesis and therapeutic targets

Exosomes are extracellular vesicles with diameters of about 100 nm that are naturally secreted by cells into body fluids. They are derived from endosomes and are wrapped in lipid membranes. Exosomes are involved in intracellular metabolism and intercellular communication. They contain nucleic acids, proteins, lipids, and metabolites from the cell microenvironment and cytoplasm. The contents of exosomes can reflect their cells' origin and allow the observation of tissue changes and cell states under disease conditions. Naturally derived exosomes have specific biomolecules that act as the "fingerprint" of the parent cells, and the contents changed under pathological conditions can be used as biomarkers for disease diagnosis. Exosomes have low immunogenicity, are small in size, and can cross the blood-brain barrier. These characteristics make exosomes unique as engineering carriers. They can incorporate therapeutic drugs and achieve targeted drug delivery. Exosomes as carriers for targeted disease therapy are still in their infancy, but exosome engineering provides a new perspective for cell-free disease therapy. This review discussed exosomes and their relationship with the occurrence and treatment of some neuropsychiatric diseases. In addition, future applications of exosomes in the diagnosis and treatment of neuropsychiatric disorders were evaluated in this review.

Sprayable alginate hydrogel dressings with oxygen production and exosome loading for the treatment of diabetic wounds

Chronic wound unhealing is a common complication in diabetic patients, which is mainly caused by tissue hypoxia, slow vascular recovery, and a long period of inflammation. Here we present a sprayable alginate hydrogel (SA) dressing consisting of oxygen-productive (CP) microspheres and exosomes (EXO) to promote local oxygen generation, accelerate macrophage towards M2 polarization, and improve cell proliferation in diabetic wounds. Results show that the release of oxygen continues for up to 7 days, reducing the expression of hypoxic factors in fibroblasts. In vivo, the diabetic wounds experiment showed that the CP/EXO/SA dressing apparently accelerated full-thickness wound healing characteristics such as the promotion of wound healing efficiency, rapid re-epithelization, favorable collagen deposition, abundant angiogenesis at the wound beds, and shortened inflammation period. EXO synergistic oxygen (CP/EXO/SA) dressing suggests a promising treatment measure for diabetic wounds.

Mechanism of immune attack in the progression of obesity-related type 2 diabetes

Obesity and overweight are widespread issues in adults, children, and adolescents globally, and have caused a noticeable rise in obesity-related complications such as type 2 diabetes mellitus (T2DM). Chronic low-grade inflammation is an important promotor of the pathogenesis of obesity-related T2DM. This proinflammatory activation occurs in multiple organs and tissues. Immune cell-mediated systemic attack is considered to contribute strongly to impaired insulin secretion, insulin resistance, and other metabolic disorders. This review focused on highlighting recent advances and underlying mechanisms of immune cell infiltration and inflammatory responses in the gut, islet, and insulin-targeting organs (adipose tissue, liver, skeletal muscle) in obesity-related T2DM. There is current evidence that both the innate and adaptive immune systems contribute to the development of obesity and T2DM.

A review of the regulatory mechanisms of extracellular vesicles-mediated intercellular communication

Extracellular vesicles (EVs) are small, membrane-bound structures that are released from cells into the surrounding environment. These structures can be categorized as exosomes, microvesicles, or apoptotic vesicles, and they play an essential role in intercellular communication. These vesicles are attracting significant clinical interest as they offer the potential for drug delivery, disease diagnosis, and therapeutic intervention. To fully understand the regulation of intercellular communication through EVs, it is essential to investigate the underlying mechanisms. This review aims to provide a summary of the current knowledge on the intercellular communications involved in EV targeting, binding, and uptake, as well as the factors that influence these interactions. These factors include the properties of the EVs, the cellular environment, and the recipient cell. As the field of EV-related intercellular communication continues to expand and techniques improve, we can expect to uncover more information about this complex area, despite the current limitations in our knowledge.

Atf4 regulates angiogenic differences between alveolar bone and long bone macrophages by regulating M1 polarization, based on single-cell RNA sequencing, RNA-seq and ATAC-seq analysis

In the repair of maxillofacial bone defects, autogenous craniofacial bone can often provide superior clinical results over long bone grafts. Most current studies have focused on the osteogenic differences between alveolar bone marrow (ABM) and long bone marrow (LBM), however, studies about the angiogenic differences between the two are currently lacking. We downloaded single-cell RNA sequencing (scRNA-seq) of mouse ABM and LBM respectively from the public database, and the data were processed by using Seurat package. CellphoneDB2 results showed that macrophages had the strongest interaction with mesenchymal stem cells (MSCs) and endothelial cells (ECs). ELISA results confirmed that ABM macrophages secreted a higher level of vascular endothelial growth factor A (Vegfa) compared to LBM macrophages, which further promoted angiogenesis of ECs and MSCs. Using SCENIC package, six key transcription factors (TFs) were identified to regulate the difference between ABM and LBM macrophages, and activating transcription factor 4 (Atf4) was confirmed to be more expressed in ABM macrophages by polymerase chain reaction (PCR) and western blot (WB), with predicted target genes including Vegfa. Besides, the result of scRNA-seq implied ABM macrophages more in M1 status than LBM macrophages, which was confirmed by the following experiments. From the results of another assay for transposase accessible chromatin sequencing (ATAC-seq) and RNA-seq about M1 macrophages, Atf4 was also confirmed to regulate the M1 polarization. So, we suspected that Atf4 regulated the different expression of Vegfa between ABM and LBM macrophages by activating M1 polarization. After knocking down Atf4, the expression of M1 polarization markers and Vegfa were downregulated and vasculogenic differences were eliminated, which were subsequently reversed by the addition of LPS/IFN-γ. Our study might provide a new idea to improve the success rate of autologous bone grafting and treatment of oral diseases.

Adipose-derived mesenchymal stem cells promote salivary duct regeneration via a paracrine effect

OBJECTIVES

The self-regeneration of exocrine tissues, including salivary glands, is limited and their regeneration mechanism has not yet been fully elucidated. Here we identify the role of adipose-derived mesenchymal stem cells (AMSCs) in salivary gland regeneration.

METHODS

AMSCs expressing mesenchymal stem cell markers were applied to a submandibular gland injury model and the mechanism of salivary gland repair and regeneration was analyzed.

RESULTS

Transplanted green fluorescent protein (GFP)-labeled AMSCs grew tightly together and promoted ductal regeneration in the regenerative nodule, with slight infiltration of nonspecific immune cells. A comprehensive gene analysis through RNA-sequencing revealed increased expression of bone morphogenetic protein (BMP), transforming growth factor (TGF), and Wnt in AMSC-transplanted regenerative nodules. The factors released from AMSCs scavenge hydrogen peroxidase-induced reactive oxygen species (ROS) through Wnt promoter activity in vitro. Furthermore, AMSC-conditioned medium recovered the growth of the hydrogen peroxidase-damaged primordium of the submandibular gland culture ex vivo.

CONCLUSIONS

These results suggest that AMSC-released factors scavenge ROS and maintain salivary gland repair and regeneration via paracrine effects. Thus, AMSCs could be a practical and applicable tool for use in salivary gland regeneration.

Exosomes for angiogenesis induction in ischemic disorders

Ischaemic disorders are leading causes of morbidity and mortality worldwide. While the current therapeutic approaches have improved life expectancy and quality of life, they are unable to "cure" ischemic diseases and instate regeneration of damaged tissues. Exosomes are a class of extracellular vesicles with an average size of 100-150 nm, secreted by many cell types and considered a potent factor of cells for paracrine effects. Since exosomes contain multiple bioactive components such as growth factors, molecular intermediates of different intracellular pathways, microRNAs and nucleic acids, they are considered as cell-free therapeutics. Besides, exosomes do not rise cell therapy concerns such as teratoma formation, alloreactivity and thrombotic events. In addition, exosomes are stored and utilized more convenient. Interestingly, exosomes could be an ideal complementary therapeutic tool for ischemic disorders. In this review, we discussed therapeutic functions of exosomes in ischemic disorders including angiogenesis induction through various mechanisms with specific attention to vascular endothelial growth factor pathway. Furthermore, different delivery routes of exosomes and different modification strategies including cell preconditioning, gene modification and bioconjugation, were highlighted. Finally, pre-clinical and clinical investigations in which exosomes were used were discussed.

Tumor Suppressor miR-613 Alleviates Non-Small Cell Lung Cancer Cell via Repressing M2 Macrophage Polarization

Background

Non-small cell lung cancer (NSCLC) is a crucial crux of cancer-related death, and M2 macrophage polarization facilitates NSCLC development. MicroRNA-613 (miR-613) is a tumor suppressor. This research aimed to clarify the miR-613 function in NSCLC and its impact on M2 macrophage polarization. Methods. miR-613 expressions in NSCLC tissues and cells were evaluated using quantitative real-time PCR. For miR-613 function in NSCLC, cell proliferation analysis, cell counting kit-8, flow cytometry, western blot, transwell, and wound-healing were conducted. Meanwhile, the miR-613 impact on M2 macrophage polarization was assessed by the NSCLC models. Results. miR-613 was lessened in NSCLC cells and tissues. It was corroborated that miR-613 overexpression retrained NSCLC cell proliferation, invasion, and migration but facilitated cell apoptosis. Moreover, miR-613 overexpression restrained NSCLC development by repressing M2 macrophage polarization.

Conclusion

Tumor suppressor miR-613 ameliorated NSCLC by restraining M2 macrophage polarization.

PER1 promotes functional recovery of mice with hindlimb ischemia by inducing anti-inflammatory macrophage polarization

Hindlimb ischemia (HLI) is an arterial occlusive disease that exposes the patients to the risk of limb gangrene and loss. Polarization of macrophages is related to HLI-induced inflammation. Period circadian regulator 1 (PER1) is a core component of the circadian clock. We first showed, based upon bioinformatics analysis of microarray data, that PER1 expression was reduced in monocytes from patients with critical limb ischemia. The proximal femoral artery in the left hindlimb of male mice was ligated and then the femoral artery and its collateral branches were removed to establish the HLI mouse model. After modeling, a single intramuscular injection of 1 × 10⁹ pfu Ad-PER1 was performed at the adductor and gastrocnemius muscles. The gastrocnemius muscle tissues were collected at day 0, 3, 7, 14, 21 post-HLI. There was obvious pathological necrosis, accompanied with reduced expression of PER1 in the muscle tissues of HLI mice. Expression of CD68 and CD31 seemed to be corresponded to PER1 in gastrocnemius muscle, implying the potential of PER1 in regulating macrophage-related inflammation and angiogenesis. PER1 overexpression diminished myocyte damage, promoted blood flow restoration and improved behavioral scores of HLI mice. Immunostaining of CD31 and α-SMA revealed that PER1 upregulation reversed HLI-induced decreases in capillary and arteriole density. In vitro, RAW264.7 cells were cultured in hypoxia (1% O₂) for 24 h. The percentage of pro-inflammatory CD86⁺ macrophages (M1 type) was decreased and that of anti-inflammatory CD206+ macrophages (M2 type) was increased when PER1 was overexpressed. Moreover, the expression levels of TNF-α, IL-6 and M1-type marker iNOS were decreased, and levels of IL-10 and M2-type marker Arg-1 were increased by PER1 in gastrocnemius muscle of HLI mice and hypoxia-treated RAW264.7 cells. PER1 might reduce M1 macrophage polarization and promote M2 macrophage polarization, and thus exert anti-inflammatory and pro-angiogenic actions. Our findings suggest that PER1 overexpression promotes functional recovery of mice with HLI through regulating macrophage polarization.

MSC-Exos: Important active factor of bone regeneration

Bone defect and repair is a common but difficult problem in restorative and reconstructive surgery. Bone tissue defects of different sizes caused by different reasons bring functional limitations and cosmetic deformities to patients. Mesenchymal stem cells (MSC), a major hotspot in the field of regeneration in recent years, have been widely used in various studies on bone tissue regeneration. Numerous studies have shown that the bone regenerative effects of MSC can be achieved through exosome-delivered messages. Although its osteogenic mechanism is still unclear, it is clear that MSC-Exos can directly or indirectly support the action of bone regeneration. It can act directly on various cells associated with osteogenesis, or by carrying substances that affect cellular activators or the local internal environment in target cells, or it can achieve activation of the osteogenic framework by binding to materials. Therefore, this review aims to summarize the types and content of effective contents of MSC-Exos in bone regeneration, as well as recent advances in the currently commonly used methods to enable the binding of MSC-Exos to the framework and to conclude that MSC-Exos is effective in promoting osteogenesis.

Extracellular vesicles derived from hypoxia-preconditioned bone marrow mesenchymal stem cells ameliorate lower limb ischemia by delivering miR-34c

Hypoxic mesenchymal stem cell-derived extracellular vesicles (EVs) have been suggested as a promising therapy for various diseases. This study aims to determine the effect of EVs derived from bone marrow mesenchymal stem cells (BMMSCs) under hypoxia on lower limb ischemia and the underlying mechanism. Human BMMSCs were subjected to hypoxia or normoxia followed by the isolation of EVs. Nanoparticle trafficking analysis (NTA), transmission electron microscopy (TEM), and Western Blotting using corresponding markers were performed to confirm the EVs. The EVs from BMMSCs under hypoxia condition (Hyp-EVs) or normoxia condition (Nor-EVs) were subjected to hindlimb ischemia (HI) mice. MiR-34c expression in BMMSCs and BMMSC-EVs was detected. The role of miR-34c in regulating M2 macrophage polarization, as well as the target of miR-34c, were explored. HI mice with Hyp-EV treatment, as compared to the Nor-EV or the PBS group, had better blood flow and higher capillary density. MiR-34c expression was increased in BMMSCs, BMMSC-EVs, and the adductor muscle of HI mice. Hyp-EVs promoted the M2 macrophage polarization and anti-inflammatory cytokine production, and enhanced the blood flow and capillary density in HI mice, while the knockdown of miR-34c partly reversed these effects. PTEN is a target of miR-34c, and the PTEN silencing facilitated M2 macrophage polarization, whereas the inhibition of AKT signaling partly abolished the effect. Hyp-EVs promoted M2 macrophage polarization by delivering miR-34c via PTEN/AKT pathway, which could be a promising therapeutic strategy to ameliorate lower limb ischemia.

Adipose tissue macrophages: implications for obesity-associated cancer

Obesity is one of the most serious global health problems, with an incidence that increases yearly and coincides with the development of cancer. Adipose tissue macrophages (ATMs) are particularly important in this context and contribute to linking obesity-related inflammation and tumor progression. However, the functions of ATMs on the progression of obesity-associated cancer remain unclear. In this review, we describe the origins, phenotypes, and functions of ATMs. Subsequently, we summarize the potential mechanisms on the reprogramming of ATMs in the obesity-associated microenvironment, including the direct exchange of dysfunctional metabolites, inordinate cytokines and other signaling mediators, transfer of extracellular vesicle cargo, and variations in the gut microbiota and its metabolites. A better understanding of the properties and functions of ATMs under conditions of obesity will lead to the development of new therapeutic interventions for obesity-related cancer.

The immunolocalization of cluster of differentiation 31, phalloidin and alpha smooth muscle actin on vascular network of normal and ischemic rat brain

Cluster of differentiation 31 (CD31), phalloidin and alpha smooth muscle actin (α-SMA) have been widely applied to label the cerebral blood vessels in the past years. Although CD31 is mainly used as endothelial marker in determining the cerebral capillaries, it seems likely that its labeling efficiency is closely correlated with the antibodies from the polyclonal or monoclonal one, as well as the conditions of blood vessels. In order to test this phenomenon, we compared the labeling characteristics of goat polyclonal anti-CD31 (gP-CD31) and mouse monoclonal anti-CD31 (mM-CD31) with those of phalloidin and α-SMA on the rat brain in health and ischemia/reperfusion (I/R) with the middle cerebral artery occlusion. By multiple immunofluorescence staining, it was found that gP-CD31 labeling expressed extensively on the cerebral capillaries forming the vascular networks on the normal and ischemic regions, but mM-CD31 labeling mainly presented on the capillaries in the ischemic region. In contrast to the vascular labeling with gP-CD31, phalloidin and α-SMA were mainly expressed on the wall of cortical penetrating arteries, and less on that of capillaries. By three-dimensional reconstruction analysis, it was clearly shown that gP-CD31 labeling was mainly located on the lumen side of vascular wall and was surrounded by phalloidin labeling and α-SMA labeling. These results indicate that gP-CD31 is more sensitive than mM-CD31 for labeling the cerebral vasculature, and is highly compatible with phalloidin and α-SMA for evaluating the cerebral vascular networks under the physiological and pathological conditions.

Recent Advancement of Functional Hydrogels toward Diabetic Wound Management

Wound healing is a dynamic, orchestrated process comprising partially overlapping phases of hemostasis, inflammation, proliferation, and remodeling. This programmed process, dysregulated in diabetic individuals, results in chronic diabetic wounds. The normal process of healing halts at the inflammatory stage, and this prolonged inflammatory phase is characteristic of diabetic wounds. There are a few U.S. Food & Drug Administration approved skin substitutes; dermal matrixes are commercially available to manage diabetic wounds. However, expensiveness and nonresponsiveness in a few instances are the major limitations of such modalities. To address the issues, several treatment strategies have been exploited to treat chronic wounds; among them hydrogel-based systems showed promise due to favorable properties such as excellent absorption capabilities, porous structure, tunable mechanical strength, and biocompatibility. In the past two decades, hydrogels have become one of the most acceptable systems in the field of wound dressing material, offering single functionality to multifunctionality. This review focuses on the advancement of functional hydrogels explored for diabetic wound management. The process of diabetic wound healing is discussed in the light of the normal healing process, and the role of macrophages in the process is explained. This review also discusses the different approaches to treat diabetic wounds using functional hydrogels, along with their future opportunities.

Mechanical stimulation improves rotator cuff tendon-bone healing via activating IL-4/JAK/STAT signaling pathway mediated macrophage M2 polarization

Background

It is well known that appropriate mechanical stimulation benefits tendon-bone (T-B) healing, however, the mechanisms behind this are still uncovered completely. Here, we aimed to explore whether the IL-4/JAK/STAT signaling pathway mediated macrophage polarization was involved in mechanical stimulation induced T-B healing.

Method

C57BL/6 mice rotator cuff (RC) repair model was established, and the mice were randomly allocated to the following group. 1. Mice were allowed for free cage activities after surgery (FC group); 2. Mice received treadmill running initiated on postoperative day 7 (TR group); 3. Mice only received a local injection of hydrogel containing IL-4 neutralizing antibody without postoperative intervention (FC ​+ ​AF-404-SP group); 4. Mice received a local injection of hydrogel containing IL-4 neutralizing antibody and postoperative treadmill running (TR ​+ ​AF-404-SP group). The expression of IL-4 within supraspinatus tendon (SST) enthesis was measured by Enzyme-linked immunosorbent assay (ELISA). In addition, the activation of JAK/STAT signaling pathway in macrophages and identification of macrophage phenotype at the RC insertion site was detected by Flow cytometry and qRT-PCR. T-B healing quality in this RC repair model was evaluated by histological staining, Micro-computed tomography (Micro-CT) scanning, and biomechanical testing.

Result

In this study, using the RC repair model, we confirmed that generation of IL-4, activation of the JAK/STAT signaling pathway in macrophages, the ability of macrophages to polarize towards M2 subtype, and T-B healing quality were significantly enhanced in TR group compared to FC group. When comparing FC ​+ ​AF-404-SP group with TR ​+ ​AF-404-SP group, it was found that the mechanical stimulation induced this effect was depleted following the blockade of the IL-4/JAK/STAT signaling pathway.

Conclusion

Our finding suggested that mechanical stimulation could accelerate T-B healing via activating the IL-4/JAK/STAT signaling pathway that modulates macrophages to polarize towards M2 subtype.

The translational potential of this article

This is the first study to reveal a significant role of mechanical stimulation in the IL-4/JAK/STAT signaling pathway activation and macrophage polarization during RC T-B healing, which highlights the IL-4/JAK/STAT signaling pathway as a potential target to mediate macrophage M2 polarization and improves T-B healing for RC repair.

Adipose-Derived Stem Cell Exosomes and Related microRNAs in Atherosclerotic Cardiovascular Disease

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death from noncommunicable diseases worldwide. The pathological development of ASCVD begins with atherosclerosis, followed by the narrowing and occlusion of the vascular lumen and, subsequently, ischemic necrosis in coronary arteries. Preventing atherosclerosis development and delaying ischemia progression may be effective ways of pre-diagnosing and treating ASCVD. Studies have demonstrated that exosomes from adipose-derived stem cells play an increasingly important role in basic research on cardiovascular diseases in terms of the impact of macrophage polarization and the endothelial, anti-apoptosis, and angiogenesis effects. The related microRNAs play a significant role in ASCVD. This study was novel in reviewing the role of exosomes from adipose-derived stem cells and related microRNAs in ASCVD. Therapeutic potentials of adipose-derived stem cell exosomes in terms of their impact on macrophage polarization, endothelial effect, anti-apoptosis intervention, and angiogenesis.

Adipose-Derived Stromal/Stem Cell Response to Tumors and Wounds: Evaluation of Patient Age

Tumors were characterized as nonhealing wounds by Virchow in 1858 and Dvorak in 1986. Since then, researchers have analyzed tumors from a new perspective. The parallels between tumorigenesis and physiological wound healing can provide a new framework for developing antitumor therapeutics. One commonality between tumors and wounds is the involvement of the stromal environment, particularly adipose stromal/stem cells (ASCs). ASCs exhibit dual functions, in which they stimulate tumor progression and assist in tissue repair and regeneration. Numerous studies have focused on the role of ASCs in cancer and wound healing, but none to date has linked age, cancer, and wound healing. Furthermore, very few studies have focused on the role of donor-specific characteristics of ASCs, such as age and their role in facilitating ASC behavior in cancer and wound healing. This review article is designed to provide important insights into the impact of donor age on ASC tumor and wound response and their role in facilitating ASC behavior in cancer and wound healing.

Exosome biopotentiated hydrogel restores damaged skeletal muscle in a porcine model of stress urinary incontinence

Urinary incontinence afflicts up to 40% of adult women in the United States. Stress urinary incontinence (SUI) accounts for approximately one-third of these cases, precipitating ~200,000 surgical procedures annually. Continence is maintained through the interplay of sub-urethral support and urethral sphincter coaptation, particularly during activities that increase intra-abdominal pressure. Currently, surgical correction of SUI focuses on the re-establishment of sub-urethral support. However, mesh-based repairs are associated with foreign body reactions and poor localized tissue healing, which leads to mesh exposure, prompting the pursuit of technologies that restore external urethral sphincter function and limit surgical risk. The present work utilizes a human platelet-derived CD41a and CD9 expressing extracellular vesicle product (PEP) enriched for NF-κB and PD-L1 and derived to ensure the preservation of lipid bilayer for enhanced stability and compatibility with hydrogel-based sustained delivery approaches. In vitro, the application of PEP to skeletal muscle satellite cells in vitro drove proliferation and differentiation in an NF-κB-dependent fashion, with full inhibition of impact on exposure to resveratrol. PEP biopotentiation of collagen-1 and fibrin glue hydrogel achieved sustained exosome release at 37 °C, creating an ultrastructural “bead on a string” pattern on scanning electron microscopy. Initial testing in a rodent model of latissimus dorsi injury documented activation of skeletal muscle proliferation of healing. In a porcine model of stress urinary incontinence, delivery of PEP-biopotentiated collagen-1 induced functional restoration of the external urethral sphincter. The histological evaluation found that sustained PEP release was associated with new skeletal muscle formation and polarization of local macrophages towards the regenerative M2 phenotype. The results provided herein serve as the first description of PEP-based biopotentiation of hydrogels implemented to restore skeletal muscle function and may serve as a promising approach for the nonsurgical management of SUI.

Mesenchymal stem cell-derived exosome-educated macrophages alleviate systemic lupus erythematosus by promoting efferocytosis and recruitment of IL-17+ regulatory T cell

Background

Anti-inflammatory polarized macrophages are reported to alleviate systemic lupus erythematosus (SLE). Our previous studies have demonstrated that exosomes from adipose-derived stem cells promote the anti-inflammatory polarization of macrophages. However, the possible therapeutic effect of exosomes from stem cells on SLE remains unexplored.

Methods

Exosomes were isolated from the conditioned medium of bone marrow-derived mesenchymal stem cells using ultrafiltration and size-exclusion chromatography and were identified by nanoparticle tracking analysis and immunoblotting of exosomal-specific markers. Macrophages were collected from the MRL/lpr mouse kidney. The phenotype of macrophages was identified by immunoblotting for intracellular markers-inducible nitric oxide synthase (iNOS) and arginase-1 (Arg-1), and flow cytometry for macrophage markers F4/80, CD86, CD206, B7H4, and CD138. Pristane-induced murine lupus nephritis models were employed for in vivo study.

Results

When macrophages from the kidney of the MRL/lpr mice were treated with exosomes from bone marrow-derived mesenchymal stem cells (BM-MSCs), the upregulation of CD206, B7H4, CD138, Arg-1, CCL20, and anti-inflammatory cytokines was observed, which suggested that the macrophages were polarized to a specific anti-inflammatory phenotype. These anti-inflammatory macrophages produced low levels of reactive oxygen species (ROS) but had a high efferocytosis activity and promoted regulatory T (T_reg) cell recruitment. Moreover, exosome injection stimulated the anti-inflammatory polarization of macrophages and increased the production of IL-17⁺ T_reg cells in a pristane-induced murine lupus nephritis model. We observed that exosomes from BMMSCs depleted of microRNA-16 (miR-16) and microRNA-21 (miR-21) failed to downregulate PDCD4 and PTEN in macrophages, respectively, and attenuated exosome-induced anti-inflammatory polarization.

Conclusion

Our findings provide evidence that exosomes from BMMSCs promote the anti-inflammatory polarization of macrophages. These macrophages alleviate SLE nephritis in lupus mice by consuming apoptotic debris and inducing the recruitment of T_reg cells. We identify that exosomal delivery of miR-16 and miR-21 is a significant contributor to the polarization of macrophages.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03174-7.

Exosomes as Neurological Nanosized Machines

In the past few decades, nanomedicine research has advanced dramatically. In spite of this, traditional nanomedicine faces major obstacles, such as blood-brain barriers, low concentrations at target sites, and rapid removal from the body. Exosomes as natural extracellular vesicles contain special bioactive molecules for cell-to-cell communications and nervous tissue function, which could overcome the challenges of nanoparticles. Most recently, microRNAs, long noncoding RNA, and circulating RNA of exosomes have been appealing because of their critical effect on the molecular pathway of target cells. In this review, we have summarized the important role of exosomes of noncoding RNAs in the occurrence of brain diseases.

Paracrine Regulation of Adipose Tissue Macrophages by Their Neighbors in the Microenvironment of Obese Adipose Tissue

Obesity has recently been defined as a chronic low-grade inflammatory disease. Obesity-induced inflammation of adipose tissue (AT) is an essential trigger for insulin resistance (IR) and related metabolic diseases. Although the underlying molecular basis of this inflammation has not been fully identified, there is consensus that the recruited and activated macrophages in AT are the most important culprits of AT chronic inflammation. Adipose tissue macrophages (ATMs) are highly plastic and could be polarized from an anti-inflammatory M2 to proinflammatory M1 phenotypes on stimulation by microenvironmental signals from obese AT. Many efforts have been made to elucidate the molecular signaling pathways of macrophage polarization; however, the upstream drivers governing and activating macrophage polarization have rarely been summarized, particularly regulatory messages from the AT microenvironment. In addition to adipocytes, the AT bed also contains a variety of immune cells, stem cells, as well as vascular, neural, and lymphatic tissues throughout, which together orchestrate the AT microenvironment. Here, we summarize how the aforesaid neighbors of ATMs in the AT microenvironment send messages to ATMs and thus regulate its phenotype during obesity. Deciphering the biology and polarization of ATMs in the obese environment is expected to provide a precise immunotherapy for adipose inflammation and obesity-related metabolic diseases.

Adipose-Derived Mesenchymal Stem Cells Combined With Extracellular Vesicles May Improve Amyotrophic Lateral Sclerosis

The complexity of central nervous system diseases together with their intricate pathogenesis complicate the establishment of effective treatment strategies. Presently, the superiority of adipose-derived mesenchymal stem cells (ADSCs) on neuronal injuries has attracted significant attention. Similarly, extracellular vesicles (EVs) are potential interventional agents that could identify and treat nerve injuries. Herein, we reviewed the potential effects of ADSCs and EVs on amyotrophic lateral sclerosis (ALS) injured nerves, and expound on their practical application in the clinic setting. This article predominantly focused on the therapeutic role of ADSCs concerning the pathogenesis of ALS, the protective and reparative effects of EVs on nerve injury, as well as the impact following the combined usage of ADSCs and EVs in ALS.

Hirudin Regulates Vascular Function in Chronic Renal Failure through Modulating Macrophage Polarization

Excessive inflammation is responsible for arteriovenous fistula (AVF) failure, which determines the therapeutic effect of chronic renal failure (CRF). Macrophage polarization is of great significance in the inflammatory response. Hirudin (Hiru) has been reported to possess a definite anti-inflammatory effect. This study is to uncover the impacts of Hiru on classically (M1)/alternatively (M2) macrophage polarization in the CRF rat model and rat vascular smooth muscle cells (VSMCs). After the CRF rat model was administrated with different concentrations of Hiru, blood urea nitrogen (BUN) and serum creatinine (Scr) levels were tested. H&E staining was to detect vascular injury, and IHC assay was to analyze inducible nitric oxide synthase (iNOS) and arginase-1 (Arg-1) expressions in vascular tissues. Levels of inflammatory factors were examined by ELISA. Besides, western blot was to estimate the levels of marker proteins related to macrophage, proliferation, and apoptosis. CCK-8 was to measure cell viability. We discovered that Hiru alleviated renal function injury and vascular injury, exacerbated VSMC hyperplasia, and stimulated the differentiation and activation of M1 macrophage towards M2 macrophage in vivo. Moreover, after treatment with lipopolysaccharide (LPS)/IFN-gamma (IFN-γ), the increased M1/M2 ratio and enhanced levels of inflammatory factors were observed. Furthermore, Hiru boosted the proliferation and ameliorated the inflammatory response and apoptosis of rat VSMCs during the process of coincubation of M1-conditioned medium (CM). Collectively, Hiru played a protective role against vascular injury in CRF directly or through its influence on M1 macrophage polarization and inflammation.

Delivery of VEGF and delta-like 4 to synergistically regenerate capillaries and arterioles in ischemic limbs

Vascularization of the poorly vascularized limbs affected by critical limb ischemia (CLI) is necessary to salvage the limbs and avoid amputation. Effective vascularization requires forming not only capillaries, but also arterioles and vessel branching. These processes rely on the survival, migration and morphogenesis of endothelial cells in the ischemic limbs. Yet endothelial cell functions are impaired by the upregulated TGFβ. Herein, we developed an injectable hydrogel-based drug release system capable of delivering both VEGF and Dll4 to synergistically restore endothelial cellular functions, leading to accelerated formation of capillaries, arterioles and vessel branching. In vitro, the Dll4 and VEGF synergistically promoted the human arterial endothelial cell (HAEC) survival, migration, and formation of filopodial structure, lumens, and branches under the elevated TGFβ1 condition mimicking that of the ischemic limbs. The synergistic effect was resulted from activating VEGFR2, Notch-1 and Erk1/2 signaling pathways. After delivering the Dll4 and VEGF via an injectable and thermosensitive hydrogel to the ischemic mouse hindlimbs, 95% of blood perfusion was restored at day 14, significantly higher than delivery of Dll4 or VEGF only. The released Dll4 and VEGF significantly increased density of capillaries and arterioles, vessel branching point density, and proliferating cell density. Besides, the delivery of Dll4 and VEGF stimulated skeletal muscle regeneration and improved muscle function. Overall, the developed hydrogel-based Dll4 and VEGF delivery system promoted ischemic limb vascularization and muscle regeneration. STATEMENT OF SIGNIFICANCE: Effective vascularization of the poorly vascularized limbs affected by critical limb ischemia (CLI) requires forming not only capillaries, but also arterioles and vessel branching. These processes rely on the survival, migration and morphogenesis of endothelial cells. Yet endothelial cell functions are impaired by the upregulated TGFβ in the ischemic limbs. Herein, we developed an injectable hydrogel-based drug release system capable of delivering both VEGF and Dll4 to synergistically restore endothelial cell functions, leading to accelerated formation of capillaries, arterioles and vessel branching.