Profibrogenic macrophage-targeted delivery of mitochondrial protector via exosome formula for alleviating pulmonary fibrosis

Pulmonary fibrosis(PF)is a devastating lung disease with limited treatment options.During this pathological process,the profibrogenic macrophage subpopulation plays a crucial role,making the characterization of this subpopulation fundamentally important.The present study revealed a positive correlation between pulmonary macrophages with higher mitochondrial mass(Mø^(mitohigh))and fibrosis.Among the Mø^(mitohigh)subpopulation of CD206^(+)M2,characterized by higher expression of dynamin 1-like(Drp1),as determined by flow cytometry and RNA-seq analysis,a therapeutic intervention was developed using an exosome-based formula composed of pathfinder and therapeutics.A pathfinder exosome called“exosome^(MMP19)(Exo^(MMP19))”,was constructed to display matrix metalloproteinase-19(^(MMP19))on the surface to locally break down the excessive extracellular matrix(ECM)in the fibrotic lung.A therapeutic exosome called“exosome therapeutics(Exo^(Tx))”,was engineered to display D-mannose on the surface while encapsulating siDrp1 inside.Prior delivery of Exo^(MMP19)degraded excessive ECM and thus paved the way for Exo^(Tx)to be delivered into Mø^(mitohigh),where Exo^(Tx)inhibited mitochondrial fission and alleviated PF.This study has not only identified Mø^(mitohigh)as profibrotic macrophages but it has also provided a potent strategy to reverse PF via a combination of formulated exosomes.

Bioinspired porous microspheres for sustained hypoxic exosomes release and vascularized bone regeneration

Exosomes derived from mesenchymal stem cells(MSCs)have demonstrated regenerative potential for cell-free bone tissue engineering,nevertheless,certain challenges,including the confined therapeutic potency of exosomes and ineffective delivery method,are still persisted.Here,we confirmed that hypoxic precondition could induce enhanced secretion of exosomes from stem cells from human exfoliated deciduous teeth(SHEDs)via comprehensive proteomics analysis,and the corresponding hypoxic exosomes(H-Exo)exhibited superior potential in promoting cellular angiogenesis and osteogenesis via the significant up-regulation in focal adhesion,VEGF signaling pathway,and thyroid hormone synthesis.Then,we developed a platform technology enabling the effective delivery of hypoxic exosomes with sustained release kinetics to irregular-shaped bone defects via injection.This platform is based on a simple adsorbing technique,where exosomes are adsorbed onto the surface of injectable porous poly(lactide-co-glycolide)(PLGA)microspheres with bioinspired polydopamine(PDA)coating(PMS-PDA microspheres).The PMS-PDA microspheres could effectively adsorb exosomes,show sustained release of H-Exo for 21 days with high bioactivity,and induce vascularized bone regeneration in 5-mm rat calvarial defect.These findings indicate that the hypoxic precondition and PMS-PDA porous microsphere-based exosome delivery are efficient in inducing tissue regeneration,hence facilitating the clinical translation of exosome-based therapy.

Adoptive transfer of metabolically reprogrammed macrophages for atherosclerosis treatment in diabetic ApoE^(-/-) mice

Atherosclerosis is characterized by inflammation in the arterial wall,which is known to be exacerbated by diabetes.Therapeutic repression of inflammation is a promising strategy for treating atherosclerosis.In this study,we showed that diabetes aggravated atherosclerosis in apolipoproteinE knockout(ApoE^(-/-))mice,in which increased expression of long-chain acyl-CoA synthetase 1(Acsl1)in macrophages played an important role.Knockdown of Acsl1 in macrophages(Mφ^(shAcsl1))reprogrammed macrophages to an anti-inflammatory phenotype,especially under hyperglycemic conditions.Injection of Mφ^(shAcsl1) reprogrammed macrophages into streptozotocin(STZ)-induced diabetic ApoE^(-/-) mice(ApoE^(-/-)+STZ)alleviated inflammation locally in the plaque,liver and spleen.Consistent with the reduction in inflammation,plaques became smaller and more stable after the adoptive transfer of reprogrammed macrophages.Taken together,our findings indicate that increased Acsl1 expression in macrophages play a key role in aggravated atherosclerosis of diabetic mice,possibly by promoting inflammation.Adoptive transfer of Acsl1 silenced macrophages may serve as a potential therapeutic strategy for atherosclerosis.

HIF1α epigenetically repressed macrophages via CRISPR/Cas9-EZH2 system for enhanced cancer immunotherapy

Immune suppressive microenvironment in tumor emerges as the main obstacle for cancer immunotherapy.In this study,we identified that HIF1α was activated in the tumor associated macrophages and acted as an important factor for the immune suppressive microenvironment.Epigenetically silencing of Hif1αvia histone H3 methylation in the promoter region was achieved by CRISPR/dCas9-EZH2 system,in which histone H3 methylase EZH2 was recruited to the promoter region specifically.The Hif1αsilenced macrophage,namely HERM(Hif1αEpigenetically Repressed Macrophage)manifested as inheritable tumor suppressing phenotype.In the subcutaneous B16-F10 melanoma syngeneic model,intratumoral injection of HERMs reprogrammed the immune suppressive microenvironment to the active one,reducing tumor burden and prolonging overall survival.Additionally,HERMs therapy remarkably inhibited tumor angiogenesis.Together,our study has not only identified a promising cellular and molecular target for reverting immune suppressive microenvironment,but also provided a potent strategy for reprogramming tumor microenvironment via epigenetically reprogrammed macrophages.

Catch bond-inspired hydrogels with repeatable and loading rate-sensitive specific adhesion

Biological receptor-ligand adhesion governed by mammalian cells involves a series of mechanochemical pro-cesses that can realize reversible,loading rate-dependent specific interfacial bonding,and even exhibit a counterintuitive behavior called catch bonds that tend to have much longer lifetimes when larger pulling forces are applied.Inspired by these catch bonds,we designed a hydrogen bonding-meditated hydrogel made from acrylic acid-N-acryloyl glycinamide(AA-NAGA)copolymers and tannic acids(TA),which formed repeatable specific adhesion to polar surfaces in an ultra-fast and robust way,but hardly adhered to nonpolar materials.It demonstrated up to five-fold increase in shear adhesive strength and interfacial adhesive toughness with external loading rates varying from 5 to 500 mm min^(-1).With a mechanochemical coupling model based on Monte Carlo simulations,we quantitatively revealed the nonlinear dependence of rate-sensitive interfacial adhesion on external loading,which was in good agreement with the experimental data.Likewise,the developed hydrogels were biocompatible,possessed antioxidant and antibacterial properties and promoted wound healing.This work not only reports a stimuli-responsive hydrogel adhesive suitable for multiple biomedical applications,but also offers an innovative strategy for bionic designs of smart hydrogels with loading rate-sensitive specific adhesion for various emerging areas including flexible electronics and soft robotics.