MSCs-laden injectable self-healing hydrogel for systemic sclerosis treatment

Mechanically regulated microcarriers with stem cell loading for skin photoaging therapy

Long-term exposure to ultraviolet radiation compromises skin structural integrity and results in disruption of normal physiological functions. Stem cells have gained attention in anti-photoaging, while controlling the tissue mechanical microenvironment of cell delivery sites is crucial for regulating cell fate and achieving optimal therapeutic performances. Here, we introduce a mechanically regulated human recombinant collagen (RHC) microcarrier generated through microfluidics, which is capable of modulating stem cell differentiation to treat photoaged skin. By controlling the cross-linking parameters, the mechanical properties of microcarriers could precisely tuned to optimize the stem cell differentiation. The microcarriers are surface functionalized with fibronectin (Fn)-platelet derived growth factor-BB (PDGF-BB) to facilitate adipose derived mesenchymal stem cells (Ad-MSCs) loading. In in vivo experiments, subcutaneous injection of stem cell loaded RHC microcarriers significantly reduced skin wrinkles after ultraviolet-injury, effectively promoted collagen synthesis, and increased vascular density. These encouraging results indicate that the present mechanically regulated microcarriers have great potential to deliver stem cells and regulate their differentiation for anti-photoaging treatments.

A Baicalin-Based Functional Polymer in Dynamic Reversible Networks Alleviates Osteoarthritis by Cellular Interactions

Osteoarthritis (OA) is increasingly recognized as a whole-organ disease predominantly affecting the elderly, characterized by typical alterations in subchondral bone and cartilage, along with recurrent synovial inflammation. Despite the availability of various therapeutics and medications, a complete resolution of OA remains elusive. In this study, novel functional hydrogels are developed by integrating natural bioactive molecules for OA treatment. Specifically, baicalin (Bai) is combined with 2-hydroxyethyl acrylate (HEA) to form a polymerizable monomer (HEA-Bai) through esterification, which is subjected to reversible addition-fragmentation chain transfer (RAFT) polymerization to produce Bai-based polymer (Pm). These macromolecules are incorporated into Schiff-base hydrogels, which demonstrate excellent mechanical properties and self-healing performance. Notably, the Bai-based formulations are taken up by fibroblast-like synoviocytes (FLSs), where they regulate glycolysis. Mechanistically, inhibition of yes-associated protein 1 (YAP1) by the formulations suppressed the FLSs glycolysis and reduced the secretion of inflammatory factors, including interleukin 1β (IL-1β), IL-6, and IL-8. Furthermore, the functional hydrogel (AG-Pm)-OC, severing as a lubricant and nutrient, prolonged joint retention of Bai, thereby reducing cartilage degradation and synovial inflammation. Meanwhile, (AG-Pm)-OC alleviated joint pain by targeting the YAP1 signaling and inhibiting macrophage recruitment and polarization. Taken together, this flavonoid-based injectable hydrogel exhibits enhanced biocompatibility and efficacy against OA.

Direct fibroblast reprogramming: an emerging strategy for treating organic fibrosis

Direct reprogramming has garnered considerable attention due to its capacity to directly convert differentiated cells into desired cells. Fibroblasts are frequently employed in reprogramming studies due to their abundance and accessibility. However, they are also the key drivers in the progression of fibrosis, a pathological condition characterized by excessive extracellular matrix deposition and tissue scarring. Furthermore, the initial stage of reprogramming typically involves deactivating fibrotic pathways. Hence, direct reprogramming offers a valuable method to regenerate target cells for tissue repair while simultaneously reducing fibrotic tendencies. Understanding the link between reprogramming and fibrosis could help develop effective strategies to treat damaged tissue with a potential risk of fibrosis. This review summarizes the advances in direct reprogramming and reveals their anti-fibrosis effects in various organs such as the heart, liver, and skin. Furthermore, we dissect the mechanisms of reprogramming influenced by fibrotic molecules including TGF-β signaling, mechanical signaling, inflammation signaling, epigenetic modifiers, and metabolic regulators. Innovative methods for fibroblast reprogramming like small molecules, CRISPRa, modified mRNA, and the challenges of cellular heterogeneity and senescence faced by in vivo direct reprogramming, are also discussed.

Extracellular Matrix-Inspired Dendrimer Nanogels Encapsulating Cyclophosphamide for Systemic Sclerosis Treatment

Cyclophosphamide has a certain therapeutic effect on treating systemic sclerosis (SSc), while difficulties exist in controlling severe systematic side effects and enhancing targeting capacity. Here, inspired from the natural extracellular matrix composition, we propose a cyclophosphamide-encapsulated nanogel based on dendritic polymers polyamidoamine (PAMAM) for SSc treatment. We combine bovine serum albumin and generation 5 (G5) PAMAM dendrimers with polyphenol modification to obtain nanogels featured with antioxidant and anti-inflammatory effects. The nanogels can possess excellent biocompatibility and prevent fibroblasts from oxidative stress damage and TGF-β-mediated activation. Furthermore, in the bleomycin-induced SSc mouse model, dendrimer nanogels encapsulating cyclophosphamide also exhibit the ability to attenuate fibrosis by modulating immunity, suppressing inflammation, and reducing collagen synthesis. These findings underscore the value of this dendritic polymer nanogel in the treatment of chronic SSc, indicating its broader potential for clinical applications.

Mesenchymal Stem Cell Exosome-Integrated Antibacterial Hydrogels for Nasal Mucosal Injury Treatment

Hydrogels have emerged as appealing prospects for wound healing due to their superior biocompatible qualities. However, the integration of antibacterial active substances into hydrogels for effective wound repair remains challenging. Here, we present a novel double-network hydrogel for nasal mucosal injury repair with antibacterial and self-healing capabilities. This hydrogel is the result of mixing aldehyde polyethylene glycol (PEG) and a carboxymethyl chitosan (CMCS)-based hydrogel with a photocured methylacrylate gelatin (GelMA) hydrogel to envelop mesenchymal stem cell exosomes (MSC-Exos). CMCS is rich in amino groups and facilitates antibacterial repair. Given the dynamically reversible Schiff base connections between the amino group of chitosan and the aldehyde group of modified PEG, the hydrogel can be easily injected into the lesion site because of its excellent injection and shear thinning properties. GelMA introduces an additional network layer for the hydrogel, which enhances its strength and extends the duration of stem cell exosomes on the wound surface. On the basis of these characteristics, we provide evidence that this compound hydrogel can substantially increase cell proliferation and regeneration, inhibit scar hyperplasia, and stimulate angiogenesis in rabbit nasal septum mucosa trauma models. These results suggest that MSC exosome-loaded hydrogels (ME-Gel) have substantial clinical potential for the repair and regeneration of nasal mucosa after surgery or trauma.

Interaction of vascular endothelial cells with hydrophilic fullerene nanoarchitectured structures in 2D and 3D environments

The interaction between diverse nanoarchitectured fullerenes and cells is crucial for biomedical applications. Here, we detailed the preparation of hydrophilic self-assembled fullerenes by the liquid-liquid interfacial precipitation (LLIP) method and hydrophilic coating of the materials as a possible vascularization strategy. The interactions of vascular endothelial cells (ECs) with hydrophilic fullerene nanotubes (FNT-P) and hydrophilic fullerene nanowhiskers (FNW-P) were investigated. The average length and diameter of FNT-P were 16 ± 2 μm and 3.4 ± 0.4 μm (i.e. aspect ratios of 4.6), respectively. The average length and diameter of FNW-P were 65 ± 8 μm and 1.2 ± 0.2 μm (i.e. aspect ratios of 53.9), respectively. For two-dimensional (2D) culture after 7 days, the ECs remained viable and proliferated up to ~ 420% and ~ 400% with FNT-P and FNW-P of 50 μg/mL, respectively. Furthermore, an optimized chitosan-based self-healing hydrogel with a modulus of ~400 Pa was developed and used to incorporate self-assembled fullerenes as in vitro three-dimensional (3D) platforms to investigate the impact of FNT-P and FNW-P on ECs within a 3D environment. The addition of FNW-P or FNT-P (50 μg/mL) in the hydrogel system led to proliferation rates of ECs up to ~323% and ~280%, respectively, after 7 days of culture. The ECs in FNW-P hydrogel displayed an elongated shape with aligned morphology, while those in FNT-P hydrogel exhibited a rounded and clustered distribution. Vascular-related gene expressions of ECs were significantly upregulated through interactions with these fullerenes. Thus, the combined use of different nanoarchitectured self-assembled fullerenes and self-healing hydrogels may offer environmental cues influencing EC development in a 3D biomimetic microenvironment, holding promise for advancing vascularization strategy in tissue engineering.

Bioadhesive Microcarriers Encapsulated with IL-27 High Expressive MSC Extracellular Vesicles for Inflammatory Bowel Disease Treatment

Mesenchymal stem cell (MSC) therapy is a promising candidate for inflammatory bowel disease (IBD) treatment, while overcoming the limitations of naive seeding cells function and realizing efficient intestinal targeting remains a challenge. Here, a bioadhesive microparticle carrying interleukin-27 (IL-27) MSC-derived extracellular vesicles (MSCIL-27 EVs) is developed to treat IBD. The MSCIL-27 EVs prepared through lentivirus-mediated gene transfection technology show ideal anti-inflammatory and damage repair function. By encapsulating MSCIL-27 EVs into dopamine methacrylamide-modified hydrogel, a bioadhesive EVs microcarrier via microfluidic technology is fabricated. The resultant microcarriers exhibit ideal MSCIL-27 EVs sustained release effect and effective wet adhesion property. Furthermore, the therapeutic potential of MSCIL-27 EVs-loaded microcarriers in treating IBD is demonstrated. Through giving IBD rats a rectal administration, it is found that the microcarriers can firmly anchor to the surface of colon, reduce the inflammatory response, and repair the damaged barrier. Therefore, the bioadhesive MSCIL-27 EVs-loaded microcarriers provide a promising strategy for the biomedical application of MSC-derived EVs, and broaden the clinical potential of MSC therapy.

Traditional Chinese Medicine Integrated Responsive Microneedles for Systemic Sclerosis Treatment

Traditional Chinese medicine, such as Tripterygium wilfordii and Paeonia lactiflora, has potential values in treating systemic sclerosis (SSc) and other autoimmune diseases, while their toxic side effect elimination and precise tropical drug delivery are still challenges. Here, we present multiple traditional Chinese medicine integrated photoresponsive black phosphorus (BP) microneedles (MNs) with the desired features for the SSc treatment. By employing a template-assisted layer-by-layer curing method, such MNs with triptolide (TP)/paeoniflorin (Pae) needle tips and BP-hydrogel needle bottoms could be well generated. The combined administration of TP and Pae can not only provide anti-inflammatory, detoxification, and immunomodulatory effects to treat skin lesions in the early stage of SSc but also remarkably reduce the toxicity of single drug delivery. Besides, the additive BPs possess good biocompatibility and near-infrared (NIR) responsiveness, imparting the MN photothermal-controlled drug release capability. Based on these features, we have demonstrated that the traditional Chinese medicine integrated responsive MNs could effectively improve skin fibrosis and telangiectasia, reduce collagen deposition, and reduce epidermal thickness in the SSc mouse models. These results indicated that the proposed Chinese medicine integrated responsive MNs had enormous potential in clinical therapy of SSc and other diseases.

ECM-Inspired Hydrogels with ADSCs Encapsulation for Rheumatoid Arthritis Treatment

Due to their intrinsic anti-inflammatory and immunomodulatory properties, adipose-derived stem cells (ADSCs) are explored as a promising alternative in treating rheumatoid arthritis (RA). To address the poor survival and function loss of directly injected stem cells, efforts in this area are focus on the generation of efficient cell delivery vehicles. Herein, a novel extracellular matrix (ECM)-inspired injectable hydrogel for ADSCs encapsulation and RA treatment is proposed. The hydrogel with dendritic polylysine and polysaccharide components is formed through the reversible Schiff base crosslinking. It possesses self-healing capability, superior mechanical properties, minimal toxicity, and immunomodulatory ability. When encapsulated with ADSCs, the hydrogel could recover chronic inflammation by directly reversing the dominant macrophage phenotype from M1 to M2 and inhibiting the migration of fibroblast-like synoviocytes. Through a collagen-induced arthritis rat model, the tremendous therapeutic outcomes of this ADSCs-laden hydrogel, including inflammation attenuation, cartilage protection, and bone mineral density promotion are demonstrated. These results make the ECM-inspired hydrogel laden with ADSCs an ideal candidate for treating RA and other autoimmune disorders.

Marine‐Derived Hydrogels for Biomedical Applications

Marine organisms provide novel and broad sources for the preparations and applications of biomaterials. Since the urgent requirement of bio‐hydrogels to mimic tissue extracellular matrix (ECM), the natural biomacromolecule hydrogels derived from marine sources have received increasing attention. Benefiting from their outstanding bioactivity and biocompatibility, many attempts have been made to reconstruct ECM components by applying marine‐derived natural hydrogels. Moreover, marine hydrogels have been successfully applied in biomedicine by means of microfluidics, electrospray, and bioprinting. In this review, the classification and characteristics of marine‐derived hydrogels are summarized. In particular, their role in the development of biomaterials is also introduced. Then, the recent advances in bio‐fabrication strategies for various hydrogel materials are focused upon. Besides, the influences of hydrogel types on their functions in biomedical applications are discussed in depth. Finally, critical reflections on the limitations and future development of marine‐derived hydrogels are presented.

Identification of lncRNA-miRNA-mRNA networks in circulating exosomes as potential biomarkers for systemic sclerosis

Objective

This study aimed to analyze potential biomarkers for systemic sclerosis (SSc) by constructing lncRNA-miRNA-mRNA networks in circulating exosomes (cirexos).

Materials and methods

Differentially expressed mRNAs (DEmRNAs) and lncRNAs (DElncRNAs) in SSc cirexos were screened using high-throughput sequencing and detected with real-time quantitative PCR (RT-qPCR). Differentially expressed genes (DEGs) were analyzed using the DisGeNET, GeneCards, GSEA4.2.3, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Receiver operating characteristic (ROC) curves, correlation analyses, and a double-luciferase reporter gene detection assay were used to analyze competing endogenous RNA (ceRNA) networks and clinical data.

Results

In this study, 286 DEmRNAs and 192 DElncRNAs were screened, of which 18 DEGs were the same as the SSc-related genes. The main SSc-related pathways included extracellular matrix (ECM) receptor interaction, local adhesion, platelet activation, and IgA production by the intestinal immune network. A hub gene, COL1A1, was obtained by a protein-protein interaction (PPI) network. Four ceRNA networks were predicted through Cytoscape. The relative expression levels of COL1A1, ENST0000313807, and NON-HSAT194388.1 were significantly higher in SSc, while the relative expression levels of hsa-miR-29a-3p, hsa-miR-29b-3p, and hsa-miR-29c-3p were significantly lower in SSc (P < 0.05). The ROC curve showed that the ENST00000313807-hsa-miR-29a-3p-COL1A1 network as a combined biomarker of SSc is more valuable than independent diagnosis, and that it is correlated with high-resolution CT (HRCT), Scl-70, C-reactive protein (CRP), Ro-52, IL-10, IgM, lymphocyte percentage, neutrophil percentage, albumin divided by globulin, urea, and RDW-SD (P < 0.05). Double-luciferase reporter gene detection showed that ENST00000313807 interacts with hsa-miR-29a-3p, which interacts with COL1A1.

Conclusion

The ENST00000313807-hsa-miR-29a-3p-COL1A1 network in plasma cirexos represents a potential combined biomarker for the clinical diagnosis and treatment of SSc.

Translation of biomaterials from bench to clinic

Scientific research originates from curiosity and interests. Translational research of biomaterials should always focus on addressing specific needs of the targeted clinical applications. The guest editors of this special issue hope that the included articles have provided cutting-edge biomaterials research as well as insights of the translation of biomaterials from bench to clinic.

Biohybrid Response Microparticles Decorated with Trained-MSCs for Acute Liver Failure Recovery

Microcarrier-based mesenchymal stem cells (MSCs) delivery have attracted increasing attention in acute liver failure (ALF) therapy, while there is still room for improvement in terms of improving cell loading efficiency, enhancing anti-inflammatory features, and controlling cell release. Here, novel lipopolysaccharide (LPS)-composited magnetic-thermal responsive inverse opal particles (MIOPs) are presented for the delivery of MSCs. The MIOPs are composed of a chitosan inverse opal skeleton filled with a hydrogel containing LPS, poly(N-isopropylacrylamide), and Fe3 O4 nanoparticles. Benefitting from the biocompatible chitosan component and the huge specific surface area, the resultant MIOPs can capture MSCs in a nondestructive way. Furthermore, LPS can be released from the MIOPs under the stimulation of an alternating magnetic field, by which the MSCs are activated to gain the feature of "trained immunity." Moreover, this process can be monitored in real-time by the structural color change of the MIOPs. With that, the MSCs-laden MIOPs are employed in rats with ALF, and they exhibit obvious anti-inflammatory and therapeutic efficacy superior to untrained MSCs. These performances make the MIOPs a distinctive cell delivery platform for clinical tissue recovery applications.

Small extracellular vesicles derived from hypoxic preconditioned dental pulp stem cells ameliorate inflammatory osteolysis by modulating macrophage polarization and osteoclastogenesis

Extensive macrophage inflammatory responses and osteoclast formation are predominant during inflammatory or infective osteolysis. Mesenchymal stem cell (MSC)-derived small extracellular vesicles (MSC-sEV) have been shown to exert therapeutic effects on bone defects. However, cultured MSCs are typically exposed to normoxia (21% O₂) in vitro, which differs largely from the oxygen concentration in vivo under hypoxic conditions. It is largely unknown whether sEV derived from dental pulp stem cells (DPSCs) cultured under hypoxic conditions (Hypo-sEV) exert better therapeutic effects on lipopolysaccharide (LPS)-induced inflammatory osteolysis than those cultured under normoxic conditions (Nor-sEV) by simultaneously inhibiting the macrophage inflammatory response and osteoclastogenesis. In this study, we show that hypoxia significantly induces the release of sEV from DPSCs. Moreover, Hypo-sEV exhibit significantly improved efficacy in promoting M2 macrophage polarization and suppressing osteoclast formation to alleviate LPS-induced inflammatory calvarial bone loss compared with Nor-sEV. Mechanistically, hypoxia preconditioning markedly alters the miRNA profiles of DPSC-sEV. MiR-210-3p is enriched in Hypo-sEV, and can simultaneously induce M2 macrophage generation and inhibit osteoclastogenesis by targeting NF-κB1 p105, which attenuates osteolysis. Our study suggests a promising potential for hypoxia-induced DPSC-sEV to treat inflammatory or infective osteolysis and identifies a novel role of miR-210-3p in concurrently hindering osteoclastogenesis and macrophage inflammatory response by inhibiting NF-kB1 expression.

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Hypoxia promotes the release of sEV from DPSCs.

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Hypoxia-induced DPSC-sEV (Hypo-sEV) show increased potential to inhibit inflammatory osteolysis.

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The miR-210-3p enriched in Hypo-sEV contributes to therapeutic effects of Hypo-sEV.

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MiR-210-3p concurrently induces M2 macrophage generation and inhibits osteoclastogenesis by targeting NF-κB1.

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Hypoxia-induced DPSC-sEV represent a promising therapy for inflammatory osteolysis.