Opsonization Inveigles Macrophages Engulfing Carrier-Free Bilirubin/JPH203 Nanoparticles to Suppress Inflammation for Osteoarthritis Therapy.

Osteoarthritis (OA) is a chronic inflammatory disease characterized by cartilage destruction, synovitis, and osteophyte formation. Disease-modifying treatments for OA are currently lacking. Because inflammation mediated by an imbalance of M1/M2 macrophages in the synovial cavities contributes to OA progression, regulating the M1 to M2 polarization of macrophages can be a potential therapeutic strategy. Basing on the inherent immune mechanism and pathological environment of OA, an immunoglobulin G-conjugated bilirubin/JPH203 self-assembled nanoparticle (IgG/BRJ) is developed, and its therapeutic potential for OA is evaluated. After intra-articular administration, IgG conjugation facilitates the recognition and engulfment of nanoparticles by the M1 macrophages. The internalized nanoparticles disassemble in response to the increased oxidative stress, and the released bilirubin (BR) and JPH203 scavenge reactive oxygen species (ROS), inhibit the nuclear factor kappa-B pathway, and suppress the activated mammalian target of rapamycin pathway, result in the repolarization of macrophages and enhance M2/M1 ratios. Suppression of the inflammatory environment by IgG/BRJ promotes cartilage protection and repair in an OA rat model, thereby improving therapeutic outcomes. This strategy of opsonization involving M1 macrophages to engulf carrier-free BR/JPH203 nanoparticles to suppress inflammation for OA therapy holds great potential for OA intervention and treatment.

BV2 Membrane-Coated PEGylated-Liposomes Delivered hFGF21 to Cortical and Hippocampal Microglia for Alzheimer's Disease Therapy.

Microglia-mediated inflammation is involved in the pathogenesis of Alzheimer's disease (AD), whereas human fibroblast growth factor 21 (hFGF21) has demonstrated the ability to regulate microglia activation in Parkinson's disease, indicating a potential therapeutic role in AD. However, challenges such as aggregation, rapid inactivation, and the blood-brain barrier hinder its effectiveness in treating AD. This study develops targeted delivery of hFGF21 to activated microglia using BV2 cell membrane-coated PEGylated liposomes (hFGF21@BCM-LIP), preserving the bioactivity of hFGF21. In vitro, hFGF21@BCM-LIP specifically targets Aß1-42-induced BV2 cells, with uptake hindered by anti-VCAM-1 antibody, indicating the importance of VCAM-1 and integrin α4/ß1 interaction in targeted delivery to BV2 cells. In vivo, following subcutaneous injection near the lymph nodes of the neck, hFGF21@BCM-LIP diffuses into lymph nodes and distributes along the meningeal lymphatic vasculature and brain parenchyma in amyloid-beta (Aß1-42)-induced mice. Furthermore, the administration of hFGF21@BCM-LIP to activated microglia improves cognitive deficits caused by Aß1-42 and reduces levels of tau, p-Tau, and BACE1. It also decreases interleukin-6  (IL-6) and tumor necrosis factor-α (TNF-α) release while increasing interleukin-10 (IL-10) release both in vivo and in vitro. These results indicate that hFGF21@BCM-LIP can be a promising treatment for AD, by effectively crossing the blood-brain barrier and targeting delivery to brain microglia via the neck-meningeal lymphatic vasculature-brain parenchyma pathways.

Bilirubin/morin self-assembled nanoparticle-engulfed collagen/polyvinyl alcohol hydrogel accelerates chronic diabetic wound healing by modulating inflammation and ameliorating oxidative stress.

Chronic diabetic wounds pose a serious threat to human health and safety because of their refractory nature and high recurrence rates. The formation of refractory wounds is associated with wound microenvironmental factors such as increased expression of proinflammatory factors and oxidative stress. Bilirubin is a potent endogenous antioxidant, and morin is a naturally active substance that possesses anti-inflammatory and antioxidant effects. Both hold the potential for diabetic wound treatment by intervening in pathological processes. In this study, we developed bilirubin/morin-based carrier-free nanoparticles (BMn) to treat chronic diabetic wounds. In vitro studies showed that BMn could effectively scavenge overproduced reactive oxygen species and suppress elevated inflammation, thereby exerting a protective effect. BMn was then loaded into a collagen/polyvinyl alcohol gel (BMn@G) for an in vivo study to maintain a moist environment for the skin and convenient biomedical applications. BMn@G exhibits excellent mechanical properties, water retention capabilities, and in vivo safety. In type I diabetic mice, BMn@G elevated the expression of the anti-inflammatory factor IL-10 and concurrently diminished the expression of the proinflammatory factor TNF-α in the tissues surrounding the wounds. Furthermore, BMn@G efficiently mediated macrophage polarization from the M1-type to the M2-type, thereby fostering anti-inflammatory effects. Additionally, BMn@G facilitated the conversion of type III collagen fiber bundles to type I collagen fiber bundles, resulting in a more mature collagen fiber structure. This study provides a promising therapeutic alternative for diabetic wound healing.

Biomaterial-assisted strategies to improve islet graft revascularization and transplant outcomes.

Islet transplantation holds significant promise as a curative approach for type 1 diabetes (T1D). However, the transition of islet transplantation from the experimental phase to widespread clinical implementation has not occurred yet. One major hurdle in this field is the challenge of insufficient vascularization and subsequent early loss of transplanted islets, especially in non-intraportal transplantation sites. The establishment of a fully functional vascular system following transplantation is crucial for the survival and secretion function of islet grafts. This vascular network not only ensures the delivery of oxygen and nutrients, but also plays a critical role in insulin release and the timely removal of metabolic waste from the grafts. This review summarizes recent advances in effective strategies to improve graft revascularization and enhance islet survival. These advancements include the local release and regulation of angiogenic factors (e.g., vascular endothelial growth factor, VEGF), co-transplantation of vascular fragments, and pre-vascularization of the graft site. These innovative approaches pave the way for the development of effective islet transplantation therapies for individuals with T1D.

Formulation strategies to provide oxygen-release to contrast local hypoxia for transplanted islets.

Islet transplantation refers to the transfusion of healthy islet cells into the diabetic recipients and reconstruction of their endogenous insulin secretion to achieve insulin independence. It is a minimally invasive surgery that holds renewed prospect as a therapeutic method for type 1 diabetes mellitus. However, poor oxygenation in the early post-transplantation period is considered as one of the major causes of islet loss and dysfunction. Due to the metabolism chacteristics, islets required a high supply of oxygen for cell survival while a hypoxia environment would lead to severe islet loss and graft failure. Emerging strategies have been proposed, including providing external oxygen and speeding up revascularization. From the perspective of formulation science, it is feasible and practical to protect transplanted islets by oxygen-release before revascularization as opposed to local hypoxia. In this study, we review the potential formulation strategies that could provide oxygen-release by either delivering external oxygen or triggering localized oxygen generation for transplanted islets.

Polyphenol-driven facile assembly of a nanosized acid fibroblast growth factor-containing coacervate accelerates the healing of diabetic wounds.

Diabetic wounds are challenging to heal due to complex pathogenic abnormalities. Routine treatment with acid fibroblast growth factor (aFGF) is widely used for diabetic wounds but hardly offers a satisfying outcome due to its instability. Despite the emergence of various nanoparticle-based protein delivery approaches, it remains challenging to engineer a versatile delivery system capable of enhancing protein stability without the need for complex preparation. Herein, a polyphenol-driven facile assembly of nanosized coacervates (AE-NPs) composed of aFGF and Epigallocatechin-3-gallate (EGCG) was constructed and applied in the healing of diabetic wounds. First, the binding patterns of EGCG and aFGF were predicted by molecular docking analysis. Then, the characterizations demonstrated that AE-NPs displayed higher stability in hostile conditions than free aFGF by enhancing the binding activity of aFGF to cell surface receptors. Meanwhile, the AE-NPs also had a powerful ability to scavenge reactive oxygen species (ROS) and promote angiogenesis, which significantly accelerated full-thickness excisional wound healing in diabetic mice. Besides, the AE-NPs suppressed the early scar formation by improving collagen remodeling and the mechanism was associated with the TGF-ß/Smad signaling pathway. Conclusively, AE-NPs might be a potential and facile strategy for stabilizing protein drugs and achieving the scar-free healing of diabetic wounds. STATEMENT OF SIGNIFICANCE: Diabetic chronic wound is among the serious complications of diabetes that eventually cause the amputation of limbs. Herein, a polyphenol-driven facile assembly of nanosized coacervates (AE-NPs) composed of aFGF and EGCG was constructed. The EGCG not only acted as a carrier but also possessed a therapeutic effect of ROS scavenging. The AE-NPs enhanced the binding activity of aFGF to cell surface receptors on the cell surface, which improved the stability of aFGF in hostile conditions. Moreover, AE-NPs significantly accelerated wound healing and improved collagen remodeling by regulating the TGF-ß/Smad signaling pathway. Our results bring new insights into the field of polyphenol-containing nanoparticles, showing their potential as drug delivery systems of macromolecules to treat diabetic wounds.

Recombinant protein drugs-based intra articular drug delivery systems for osteoarthritis therapy.

Osteoarthritis (OA) is the most prevalent chronic degenerative joint disease. It weakens the motor function of patients and imposes a significant economic burden on society. The current medications commonly used in clinical practice do not meet the need for the treatment of OA. Recombinant protein drugs (RPDs) can treat OA by inhibiting inflammatory pathways, regulating catabolism/anabolism, and promoting cartilage repair, thereby showing promise as disease-modifying OA drugs (DMOADs). However, the rapid clearance and short half-life of them in the articular cavity limit their clinical translation. Therefore, the reliable drug delivery systems for extending drug treatment are necessary for the further development. This review introduces RPDs with therapeutic potential for OA, and summarizes their research progress on related drug delivery systems, and make proper discussion on the certain keys for optimal development of this area.

Evaluation of the hepatoprotective effect of naringenin loaded nanoparticles against acetaminophen overdose toxicity.

Acute liver injury is a common clinical disease, which easily leads to liver failure and endangers life, seriously threatening human health. Naringenin is a natural flavonoid that holds therapeutic potential against various liver injuries; however it has poor water solubility and bioavailability. In this study, we aimed to develop naringenin-loaded bovine serum albumin nanoparticles (NGNPs) and to evaluate their hepatoprotective effect and underlying mechanisms against acetaminophen overdose toxicity. In vitro data indicated that NGNPs significantly increased the drug solubility and also more effectively protected the hepatocyte cells from oxidative damage during hydrogen peroxide exposure or lipopolysaccharide (LPS) stimulation. In vivo results confirmed that NGNPs showed an enhanced accumulation in the liver tissue. In the murine model of acetaminophen-induced hepatotoxicity, NGNPs could effectively alleviate the progression of acute liver injury by reducing drug overdose-induced levels of oxidative stress, inflammation and apoptosis in hepatocytes. In conclusion, NGNPs has strong hepatoprotective effects against acetaminophen induced acute liver injury.

Immune-Protective Formulations and Process Strategies for Improved Survival and Function of Transplanted Islets.

Type 1 diabetes (T1D) is an autoimmune disease caused by the immune system attacking and destroying insulin-producing ß cells in the pancreas. Islet transplantation is becoming one of the most promising therapies for T1D patients. However, its clinical use is limited by substantial cell loss after islet infusion, closely related to immune reactions, including instant blood-mediated inflammatory responses, oxidative stress, and direct autoimmune attack. Especially the grafted islets are not only exposed to allogeneic immune rejection after transplantation but are also subjected to an autoimmune process that caused the original disease. Due to the development and convergence of expertise in biomaterials, nanotechnology, and immunology, protective strategies are being investigated to address this issue, including exploring novel immune protective agents, encapsulating islets with biomaterials, and searching for alternative implantation sites, or co-transplantation with functional cells. These methods have significantly increased the survival rate and function of the transplanted islets. However, most studies are still limited to animal experiments and need further studies. In this review, we introduced the immunological challenges for islet graft and summarized the recent developments in immune-protective strategies to improve the outcomes of islet transplantation.

Intradermal injection of icariin-HP-ß-cyclodextrin improved traumatic brain injury via the trigeminal epineurium-brain dura pathway.

The lower bioavailability after oral administration limited icariin applications in central nervous system. Icariin/HP-ß-cyclodextrin (HP-ß-CD) inclusion complex was prepared for acute severe opening traumatic brain injury (TBI) via facial intradermal (i.d.) in the mystacial pad. After fluid percussion-induced TBI, icariin/HP-ß-CD at 0.4 mg/kg i.d. preserved more neurons and oligodendrocytes than intranasal injection (i.n.) or intravenous injection via tail vein (i.v.) and decreased microglia and astrocyte activation. Icariin/HP-ß-CD i.d. reduced apoptosis in cortical penumbra while i.n. and i.v. showed weak or no effects. Icariin/HP-ß-CD i.d. reduced Evans blue leakage and altered CD34, ZO-1, Claudin-5, and beta-catenin expression after TBI. Moreover, icariin/HP-ß-CD promoted human umbilical vein endothelial cells proliferation. Thus, Icariin/HP-ß-CD i.d. improved TBI, including blood-brain barrier opening. Fluorescein 5-isothiocyanate (FITC) and 3,3'-Dioctadecyloxacarbocyanine perchlorate (DiOC18(3)) mimic HP-ß-CD and icariin respectively. FITC and DiOC18(3) were similarly delivered to trigeminal epineurium, perineurium and perivascular spaces or tissues, caudal dura mater, and scattered in trigeminal fasciculus, indicating that icariin/HP-ß-CD was delivered to the brain via trigeminal nerve-dura mater-brain pathways. In sum, intradermal injection in mystacial pad might deliver icariin/HP-ß-CD to the brain and icariin/HP-ß-CD improved acute severe opening TBI.

Self-Cross-Linked Hydrogel of Cysteamine-Grafted γ-Polyglutamic Acid Stabilized Tripeptide KPV for Alleviating TNBS-Induced Ulcerative Colitis in Rats.

KPV (Lys-Pro-Val), which is a tripeptide derived from α-MSH (α-melanocyte-stimulating hormone), has an anti-inflammatory effect on colitis. However, KPV solution is very unstable when rectally administered, compromising its therapeutic efficacy. Herein, cysteamine-grafted γ-polyglutamic acid (SH-PGA) was synthesized by conjugating cysteamine with the carboxyl groups of γ-PGA. The synthesized SH-PGA has the thiol grafting amount of 4.5 ± 0.3 mmol/g. Without the use of the cross-linker, the SH-PGA hydrogel with 4% of the polymer was formed by self-cross-linking of thiol groups. Moreover, the formation of the SH-PGA hydrogel was not affected by KPV. The KPV/SH-PGA hydrogel presented higher elastic modulus (G') than the corresponding viscous modulus (G″) at 0.01-10 Hz, exhibiting good mechanical stability. The KPV/SH-PGA hydrogel presented a shear-thinning behavior, which was helpful for rectal administration. Only 30% of KPV was released from the KPV/SH-PGA hydrogel within 20 min, followed by a sustained-release behavior. Importantly, the stability of KPV in the SH-PGA hydrogel was obviously enhanced, which was presented by detecting its anti-inflammatory activity and promoting cell migration potential after 2 h of exposure to 37 °C. The enhanced therapeutic effect of the KPV/SH-PGA hydrogel on colitis was confirmed on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced ulcerative colitis rats. The colitis symptoms including body weight loss and the disease activity index score were obviously attenuated by rectally administering the KPV/SH-PGA hydrogel. Besides, the KPV/SH-PGA hydrogel treatment prevented the colon shortening of TNBS-infused rats and decreased the colonic myeloperoxidase level. The morphology of the colon including the epithelial barrier, crypt, and intact goblet cells was recovered after KPV/SH-PGA hydrogel treatment. Besides, the KPV/SH-PGA hydrogel decreased the expression of proinflammatory cytokines such as tumor necrosis factor α and interleukin 6. Collectively, the KPV/SH-PGA hydrogel may provide a promising strategy for the treatment of ulcerative colitis.

Disulfiram-loaded copper sulfide nanoparticles for potential anti-glioma therapy.

Disulfiram (DSF) is an effective copper (Cu2+)-dependent antitumor agent. In the present study, we explored use of transferrin (Tf)-modified DSF/copper sulfide (CuS) nanocomplex (Tf-DSF/CuS) for glioma therapy. Tf was used as glioma targeting motifs, DSF as an anticancer agent, and CuS as a source of Cu2+ ions and a photothermal agent. DSF was loaded on CuS by metal-chelation, and released from the nanocomplex under acidic condition. The Tf-DSF/CuS complex exhibited high cytotoxic effect in vitro. Notably, cytotoxic activity was correlated with pH triggered release of Cu2+ which initiated non-toxicity to toxicity switch of DSF. Ultrasound-targeted microbubble destruction (UTMD) technique was used for highly selective accumulation of intravenous injected Tf-DSF/CuS in the glioma orthotopic tumor as compared with the free drugs and non-targeted DSF/CuS groups. Magnetic resonance imaging and pathological examinations showed that Tf-DSF/CuS effectively suppressed tumor growth, with an inhibition ratio of ~85%. Additionally, DSF load did not compromise photothermal conversion ability of CuS nanoparticles. Efficacy of the photothermal ablation therapy of Tf-DSF/CuS was evaluated under 808 nm laser irradiation both in vitro and in vivo. These findings show that copper-sulfide based disulfiram nanoparticles are effective agents for anti-glioma therapy.

Ganoderma Lucidum Polysaccharides Enhance the Abscopal Effect of Photothermal Therapy in Hepatoma-Bearing Mice Through Immunomodulatory, Anti-Proliferative, Pro-Apoptotic and Anti-Angiogenic.

Hepatocellular carcinoma is a malignant tumor with high morbidity and mortality, a highly effective treatment with low side effects and tolerance is needed. Photothermal immunotherapy is a promising treatment combining photothermal therapy (PTT) and immunotherapy. PTT induces the release of tumor-associated antigens by ablating tumor and Ganoderma lucidum polysaccharides (GLP) enhance the antitumor immunity. Results showed that Indocyanine Green (ICG) was successfully encapsulated into SF-Gel. ICG could convert light to heat and SF-Gel accelerates the photothermal effect in vitro and in vivo. PTT based on ICG/ICG-SF-Gel inhibited the growth of primary and distal tumors, GLP enhanced the inhibitory efficacy. ICG/ICG-SF-Gel-based PTT and GLP immunotherapy improved the survival time. ICG/ICG-SF-Gel-based PTT induces tumor necrosis and GLP enhanced the photothermal efficacy. ICG/ICG-SF-Gel-based PTT inhibited cell proliferation and angiogenesis, induced cell apoptosis, enhanced cellular immunity, and GLP enhanced these effects. In conclusion, GLP could enhance the abscopal effect of PTT in Hepatoma-bearing mice.

Hyaluronic acid coated bilirubin nanoparticles attenuate ischemia reperfusion-induced acute kidney injury.

Acute kidney injury (AKI) is a common pathological process that is globally associated with a high morbidity and mortality rate. The underlying AKI mechanisms include over-produced reactive oxygen species (ROS), inflammatory cell infiltration, and high levels of inflammatory mediators. Bilirubin is an endogenous compound with antioxidant, anti-inflammatory and anti-apoptotic properties, and could, therefore, be a promising therapeutic candidate. Nanotechnology-mediated therapy has emerged as a novel drug delivery strategy for AKI treatment. In this study, we report a hyaluronic acid (HA) coated ε-polylysine-bilirubin conjugate (PLBR) nanoparticle (nHA/PLBR) that can selectively accumulate in injured kidneys and alleviate the oxidative/inflammatory-induced damage. The in vitro study revealed that nHA/PLBR has good stability, biocompatibility, and exhibited higher antioxidant as well as anti-apoptotic effects when compared to nPLBR or bilirubin. The in vivo study showed that nHA/PLBR could target and accumulate in the injured kidney, effectively relieve oxidative stress and inflammatory reactions, protect the structure and function of the mitochondria, and more importantly, inhibit the apoptosis of tubular cells in an ischemia/reperfusion-induced AKI rat model. Therefore, nHA/PLBR has the capacity to enhance specific biodistribution and delivery efficiency of bilirubin, thereby providing better treatment for AKI in the future.

Magnetic PLGA microspheres loaded with SPIONs promoted the reconstruction of bone defects through regulating the bone mesenchymal stem cells under an external magnetic field.

Superparamagnetic iron oxide nanoparticles (SPIONs) have been presented to regulate the migration and osteogenic differentiation of bone mesenchymal stem cells (BMSCs) under magnetic field (MF). However, the toxicity and short residence for the massively exposed SPIONs at bone defects compromises their practical application. Herein, SPIONs were encapsulated into PLGA microspheres to overcome these shortcomings. Three types of PLGA microspheres (PFe-I, PFe-II and PFe-III) were prepared by adjusting the feeding amount of SPIONs, in which the practical SPIONs loading amounts was 1.83%, 1.38% and 1.16%, respectively. The average diameter of the fabricated microspheres ranged from 160 µm to 200 µm, having the porous and rough surfaces displayed by SEM. Moreover, they displayed the magnetic property with a saturation magnetization of 0.16 emu/g. In vitro cell studies showed that most of BMSCs were adhered on the surface of PFe-II microspheres after 2 days of co-culture. Moreover, the osteoblasts differentiation of BMSCs was significantly promoted by PFe-II microspheres after 2 weeks of co-culture, as shown by detecting osteogenesis-related proteins expressions of ALP, COLI, OPN and OCN. Afterward, PFe-II microspheres were surgically implanted into the defect zone of rat femoral bone, followed by exposure to an external MF, to evaluate their bone repairing effect in vivo. At 6th week after treatment with PFe-II + MF, the bone mineral density (BMD, 263.97 ± 25.99 mg/cm3), trabecular thickness (TB.TH, 0.58 ± 0.08 mm), and bone tissue volume/total tissue volume (BV/TV, 78.28 ± 5.01%) at the defect zone were markedly higher than that of the PFe-II microspheres alone (BMD, 194.34 ± 26.71 mg/cm3; TB.TH, 0.41 ± 0.07 mm; BV/TV, 50.49 ± 6.41%). Moreover, the higher expressions of ALP, COLI, OPN and OCN in PFe-II + MF group were displayed in the repairing bone. Collectively, magnetic PLGA microspheres together with MF may be a promising strategy for repairing bone defects.

HA/MgO nanocrystal-based hybrid hydrogel with high mechanical strength and osteoinductive potential for bone reconstruction in diabetic rats.

Bone repair and regeneration processes are markedly impaired in diabetes mellitus (DM). Intervening approaches similar to those developed for normal healing conditions have been adopted to combat DM-associated bone regeneration. However, limited outcomes were achieved for these approaches. Hence, together with osteoconductive hydroxyapatite (HA) nanocrystals, osteoinductive magnesium oxide (MgO) nanocrystals were uniformly mounted into the network matrix of an organic hydrogel composed of cysteine-modified γ-polyglutamic acid (PGA-Cys) to construct a hybrid and rough hydrogel scaffold. It was hypothesized that the HA/MgO nanocrystal hybrid hydrogel (HA/MgO-H) scaffold can significantly promote bone repair in DM rats via the controlled release of Mg2+. The HA/MgO-H scaffold exhibited a sponge-like morphology with porous 3D networks inside it and displayed higher mechanical strength than a PGA-Cys scaffold. Meanwhile, the HA/MgO-H scaffold gradually formed a tough hydrogel with G' of more than 1000 Pa after hydration, and its high hydration swelling ratio was still retained. Moreover, after the chemical degradation of the dispersed MgO nanocrystals, slow release of Mg2+ from the hydrogel matrix was achieved for up to 8 weeks because of the chelation between Mg2+ and the carboxyl groups of PGA-Cys. In vitro cell studies showed that the HA/MgO-H scaffold could not only effectively promote the migration and proliferation of BMSCs but could also induce osteogenic differentiation. Moreover, in the 8th week after implanting the HA/MgO-H scaffold into femur bone defect zones of DM rats, more effective bone repair was presented by micro-CT imaging. The bone mineral density (397.22 ± 16.36 mg cm-3), trabecular thickness (0.48 ± 0.07 mm), and bone tissue volume/total tissue volume (79.37 ± 7.96%) in the HA/MgO-H group were significantly higher than those in the other groups. Moreover, higher expression of COL-I and OCN after treatment with HA/MgO-H was also displayed. The bone repair mechanism of the HA/MgO-H scaffold was highly associated with reduced infiltration of pro-inflammatory macrophages (CD80+) and higher angiogenesis (CD31+). Collectively, the HA/MgO-H scaffold without the usage of bioactive factors may be a promising biomaterial to accelerate bone defect healing under diabetes mellitus.

Glucose-responsive hydrogel enhances the preventive effect of insulin and liraglutide on diabetic nephropathy of rats.

Diabetic nephropathy (DN) is one of the most serious complications of diabetes mellitus. The combination of insulin (Ins) with liraglutide (Lir) has a greater potential for preventing DN than monotherapy. However, the renal protective effect of the combined Ins/Lir therapy is largely compromised due to their short half-lives after subcutaneous injection. Herein, a glucose-responsive hydrogel was designed in situ forming the dynamic boronic esters bonds between phenylboronic acid-grafted γ-Polyglutamic acid (PBA-PGA) and konjac glucomannan (KGM). It was hypothesized that the KGM/PBA-PGA hydrogel as the delivery vehicle of Ins/Lir would enhance the combinational effect of the latter on preventing the DN progress. Scan electronic microscopy and rheological studies showed that KGM/PBA-PGA hydrogel displayed good glucose-responsive property. Besides, the glucose-sensitive release profile of either Ins or Lir from KGM/PBA-PGA hydrogel was uniformly displayed at hyperglycemic level. Furthermore, the preventive efficacy of KGM/PBA-PGA hydrogel incorporating insulin and liraglutide (Ins/Lir-H) on DN progress was evaluated on streptozotocin-induced rats with diabetic mellitus (DM). At 6 weeks after subcutaneous injection of Ins/Lir-H, not only the morphology of kidneys was obviously recovered as shown by ultrasonography, but also the renal hemodynamics was significantly improved. Meanwhile, the 24-h urinary protein and albumin/creatinine ratio were well modulated. Inflammation and fibrosis were also largely inhibited. Besides, the glomerular NPHS-2 was obviously elevated after treatment with Ins/Lir-H. The therapeutic mechanism of Ins/Lir-H was highly associated with the alleviation of oxidative stress and activation of autophagy. Conclusively, the better preventive effect of the combined Ins/Lir via KGM/PBA-PGA hydrogel on DN progress was demonstrated as compared with their mixed solution, suggesting KGM/PBA-PGA hydrogel might be a potential vehicle of Ins/Lir to combat the progression of DN.

Polylysine-bilirubin conjugates maintain functional islets and promote M2 macrophage polarization.

Macrophage polarization is one of the main factors contributing to the proinflammatory milieu of transplanted islets. It causes significant islet loss. Bilirubin exhibits protective effects during the islet transplantation process, but the mode of delivering drugs along with the islet graft has not yet been developed. In addition, it remains unclear whether bilirubin or its derivatives can modulate macrophage polarization during islet transplantation. Therefore, this study aimed to develop an ε-polylysine-bilirubin conjugate (PLL-BR) to encapsulate the islets for protection and to explore its macrophage modulation activities. In in vitro studies, the PLL-BR was shown to tightly adhere to the islet surface. It also exhibited enhanced cytoprotective effects against oxidative and inflammatory conditions by promoting M2-type macrophage polarization. In in vivo studies, the PLL-BR-protected islets successfully prolonged the euglycemia period in diabetic mice and accelerated the blood glucose clearance rate by maintaining the insulin secretion function. Compared to the untreated islets, the PLL-BR-encapsulated islets induced anti-inflammatory responses that were characterized by elevated levels of M2 macrophage markers and local vascularization. In conclusion, PLL-BR can be used as a tool for reprograming macrophage polarization while providing a more efficient immune protection for transplanted islets. STATEMENT OF SIGNIFICANCE: Macrophage polarization is one main factor that caused significant loss of transplanted islets. Bilirubin possesses protective effects toward pancreatic islet, but how to deliver the drug along with the islet graft has not yet been harnessed. More importantly, whether bilirubin or its derivatives could modulate macrophage polarization during the host rejections has also not been answered. In this study, we developed an ε-polylysine-bilirubin conjugate (PLL-BR) to encapsulate the islets and explore its role in macrophage modulation activities. PLL-BR could attach to the surface of islets and exerted high oxidation resistance and anti-inflammatory effect. For the first time, we demonstrate that bilirubin and its derivatives effectively promoted the M2-type macrophage polarization, and optimize the immune microenvironment for islets survival and function.

Fibroblast growth factor 2 exacerbates inflammation in adipocytes through NLRP3 inflammasome activation.

Chronic inflammation in adipose tissue is the hallmark of obesity and a major risk factor for the development of obesity-induced insulin resistance. NLRP3 inflammasome regulates the maturation and secretion of pro-inflammatory cytokines, such as IL-1ß and IL-18, and was recently discovered to be involved in obesity-related metabolic diseases. Fibroblast growth factors (FGFs) such as FGF1, FGF10, and FGF21 are adipokines that regulate adipocyte development and metabolism, but reports on the effect of other FGFs on adipocytes are lacking. In the present study, the novel role of FGF2 in NLRP3 inflammasome activation was elucidated. Our results showed that FGF2 levels were increased during adipocyte differentiation and in the adipose tissue of high-fat diet (HFD)-induced obese mice. Recombinant FGF2 treatment upregulated inflammasome markers such as NLRP3, which was further exaggerated by TNF-ɑ treatment. Interestingly, ß-Klotho, a co-receptor of FGF21, was significantly decreased by FGF2 treatment. Results from mice confirmed the positive correlation between FGF2 and NLRP3 expression in epididymal and subcutaneous adipose tissue, while exercise training effectively reversed HFD-induced NLRP3 expression as well as FGF2 levels in both adipose depots. Our results suggest that FGF2 is an adipokine that may exacerbate the inflammatory response in adipocytes through NLRP3 inflammasome activation.

Bioinspired biliverdin/silk fibroin hydrogel for antiglioma photothermal therapy and wound healing.

Rationale: Photothermal therapy employs the photoabsorbers to generate heat under the near-infrared (NIR) irradiation for thermal tumor ablation. However, NIR irradiation might damage the adjacent tissue due to the leakage of the photoabsorbers and the residual materials after treatment might hinder the local healing process. A bifunctional hydrogel that holds both photothermal property and potent pro-healing ability provides a viable option to resolve this issue. Methods: In this study, we developed a bioinspired green hydrogel (BVSF) with the integration of bioproduct biliverdin into natural derived silk fibroin matrix for antiglioma photothermal therapy and wound healing. Results: The BVSF hydrogel possessed excellent and controllable photothermal activity under NIR irradiation and resulted in effective tumor ablation both in vitro and in vivo. Additionally, the BVSF hydrogel exerted anti-inflammatory effects both in vitro and in vivo, and stimulated angiogenesis and wound healing in a full-thickness defect rat model. Conclusion: Overall, this proof-of-concept study was aimed to determine the feasibility and reliability of using an all-natural green formulation for photothermal therapy and post-treatment care.