Inhibiting the cGAS-STING Pathway in Ulcerative Colitis with Programmable Micelles.

Ulcerative colitis is a chronic condition in which a dysregulated immune response contributes to the acute intestinal inflammation of the colon. Current clinical therapies often exhibit limited efficacy and undesirable side effects. Here, programmable nanomicelles were designed for colitis treatment and loaded with RU.521, an inhibitor of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway. STING-inhibiting micelles (SIMs) comprise hyaluronic acid-stearic acid conjugates and include a reactive oxygen species (ROS)-responsive thioketal linker. SIMs were designed to selectively accumulate at the site of inflammation and trigger drug release in the presence of ROS. Our in vitro studies in macrophages and in vivo studies in a murine model of colitis demonstrated that SIMs leverage HA-CD44 binding to target sites of inflammation. Oral delivery of SIMs to mice in both preventive and delayed therapeutic models ameliorated colitis's severity by reducing STING expression, suppressing the secretion of proinflammatory cytokines, enabling bodyweight recovery, protecting mice from colon shortening, and restoring colonic epithelium. In vivo end points combined with metabolomics identified key metabolites with a therapeutic role in reducing intestinal and mucosal inflammation. Our findings highlight the significance of programmable delivery platforms that downregulate inflammatory pathways at the intestinal mucosa for managing inflammatory bowel diseases.

In situ hypoxia modulating nano-catalase for amplifying DNA damage in radiation resistive colon tumors.

Radiation therapy (RT) is a mainstream clinical approach in cancer treatment. However, the therapeutic efficacy of RT is greatly hindered by the presence of excessive hydrogen peroxide (H2O2) in the hypoxic region of the solid tumor, thus leading to tumor recurrence and metastasis. Herein, a thioketal-linked amphiphilic nano-assembly (MTS) loaded with hydrophobic manganese oxide (HMO) nanoparticles (MTS@HMO) is examined as a promising multi-purpose reactive oxygen species (ROS)-catalytic nanozyme for transforming an RT-resistant hypoxic tumor microenvironment (TME) into an RT-susceptible one by scavenging ROS in the hypoxic core of the solid tumor. After intravenous injection, the MTS@HMO nano-assembly was able to sense and be degraded by the abundant ROS in the hypoxic TME, thereby releasing HMO particles for subsequent scavenging of H2O2. The oxygen generated during peroxide scavenging then relieved the hypoxic TME, thereby resulting in an increased sensitivity of the hypoxic tumor tissue towards RT. Moreover, the in situ hypoxic status was monitored via the T1-enhanced magnetic resonance (MR) imaging of the Mn2+ ions generated by the ROS-mediated degradation of HMO. The in vitro results demonstrated a significant H2O2 elimination and enhanced oxygen generation after the treatment of the MTS@HMO nano-assembly with tumor cells under hypoxic conditions, compared to the control MTS group. In addition, the combination of RT and pre-treatment with MTS@HMO nano-assembly significantly amplified the permanent DNA strand breaks in tumor cells compared to the control RT group. More importantly, the in vivo results proved that the systemic injection of the MTS@HMO nano-assembly prior to RT irradiation enhanced the RT-mediated tumor suppression and down-regulated the hypoxic marker of HIF-1α in the solid tumor compared to the control RT group. Overall, the present work demonstrates the great potential of the versatile ROS-catalytic hypoxia modulating strategy using the MTS@HMO nano-assembly to enhance the RT-induced antitumor efficacy in hypoxic solid tumors.

Inflammation-sensing catalase-mimicking nanozymes alleviate acute kidney injury via reversing local oxidative stress.

BACKGROUND: The reactive oxygen species (ROS) and inflammation, a critical contributor to tissue damage, is well-known to be associated with various disease. The kidney is susceptible to hypoxia and vulnerable to ROS. Thus, the vicious cycle between oxidative stress and renal hypoxia critically contributes to the progression of chronic kidney disease and finally, end-stage renal disease. Thus, delivering therapeutic agents to the ROS-rich inflammation site and releasing the therapeutic agents is a feasible solution. RESULTS: We developed a longer-circulating, inflammation-sensing, ROS-scavenging versatile nanoplatform by stably loading catalase-mimicking 1-dodecanethiol stabilized Mn3O4 (dMn3O4) nanoparticles inside ROS-sensitive nanomicelles (PTC), resulting in an ROS-sensitive nanozyme (PTC-M). Hydrophobic dMn3O4 nanoparticles were loaded inside PTC micelles to prevent premature release during circulation and act as a therapeutic agent by ROS-responsive release of loaded dMn3O4 once it reached the inflammation site. CONCLUSIONS: The findings of our study demonstrated the successful attenuation of inflammation and apoptosis in the IRI mice kidneys, suggesting that PTC-M nanozyme could possess promising potential in AKI therapy. This study paves the way for high-performance ROS depletion in treating various inflammation-related diseases.

Hyaluronan-coated Prussian blue nanoparticles relieve LPS-induced peritonitis by suppressing oxidative species generation in tissue-resident macrophages.

Excessive inflammatory response during sepsis causes irreversible damage to healthy tissues and results in multi-organ failure. During infection, bacterial endotoxin-triggered inflammatory responses in macrophages facilitate the recruitment of circulating leukocytes, including neutrophils and monocytes. A key component that aggravates the systemic inflammatory response is the generation of stable reactive oxygen species such as hydrogen peroxide (H2O2). In this study, we present a versatile strategy to reduce the activation of tissue-resident macrophages and prevent leukocyte infiltration in an LPS-induced endotoxemia model. We designed and synthesized hyaluronic acid-stabilized Prussian blue (HAPB) nanoparticles and validated their activity in the dismutation of H2O2 in LPS-induced tissue-resident macrophages. Hyaluronic acid provided stability and enhanced the intracellular uptake of insoluble Prussian blue via the CD44 receptor on LPS-activated macrophages. Following HAPB administration to an LPS-induced peritonitis murine model, the level of M1 inflammatory macrophage population decreased, and the infiltration of neutrophils along with monocytes was suppressed. Overall, we have developed biocompatible Prussian blue nanoparticles to ameliorate inflammatory stress in LPS-induced endotoxemia by scavenging the intracellular peroxide thereby inhibiting inflammatory cascade in tissue-resident macrophages. Therefore, HAPB nanoparticles may potentially be used as novel nano-stress relievers in sepsis. The nanomaterials may have clinical application in sepsis and in other inflammatory diseases involving peroxides as key inflammatory agents.

Vimentin Targeted Nano-gene Carrier for Treatment of Renal Diseases.

BACKGROUND: Chronic kidney disease (CKD) is a global health problem, and there is no permanent treatment for reversing kidney failure; thus, early diagnosis and effective treatment are required. Gene therapy has outstanding potential; however, the lack of safe gene delivery vectors, a reasonable transfection rate, and kidney targeting ability limit its application. Nanoparticles can offer innovative ways to diagnose and treat kidney diseases as they facilitate targetability and therapeutic efficacy. METHODS: Herein, we developed a proximal renal tubule-targeting gene delivery system based on alternative copolymer (PS) of sorbitol and polyethyleneimine (PEI), modified with vimentin-specific chitobionic acid (CA), producing PS-conjugated CA (PSC) for targeting toward vimentin-expressing cells in the kidneys. In vitro studies were used to determine cell viability, transfection efficiency, serum influence, and specific uptake in the human proximal renal tubular epithelial cell line (HK-2). Finally, the targeting efficiency of the prepared PSC gene carriers was checked in a murine model of Alport syndrome. RESULTS: Our results suggested that the prepared polyplex showed low cytotoxicity, enhanced transfection efficiency, specific uptake toward HK-2 cells, and excellent targeting efficiency toward the kidneys. CONCLUSION: Collectively, from these results it can be inferred that the PSC can be further evaluated as a potential gene carrier for the kidney-targeted delivery of therapeutic genes for treating diseases.

Glycol chitosan-based tacrolimus-loaded nanomicelle therapy ameliorates lupus nephritis.

BACKGROUND: Recently, we developed hydrophobically modified glycol chitosan (HGC) nanomicelles loaded with tacrolimus (TAC) (HGC-TAC) for the targeted renal delivery of TAC. Herein, we determined whether the administration of the HGC-TAC nanomicelles decreases kidney injury in a model of lupus nephritis. Lupus-prone female MRL/lpr mice were randomly assigned into three groups that received intravenous administration of either vehicle control, an equivalent dose of TAC, or HGC-TAC (0.5 mg/kg TAC) weekly for 8 weeks. Age-matched MRL/MpJ mice without Faslpr mutation were also treated with HGC vehicle and used as healthy controls. RESULTS: Weekly intravenous treatment with HGC-TAC significantly reduced genetically attributable lupus activity in lupus nephritis-positive mice. In addition, HGC-TAC treatment mitigated renal dysfunction, proteinuria, and histological injury, including glomerular proliferative lesions and tubulointerstitial infiltration. Furthermore, HGC-TAC treatment reduced renal inflammation and inflammatory gene expression and ameliorated increased apoptosis and glomerular fibrosis. Moreover, HGC-TAC administration regulated renal injury via the TGF-ß1/MAPK/NF-κB signaling pathway. These renoprotective effects of HGC-TAC treatment were more potent in lupus mice compared to those of TAC treatment alone. CONCLUSION: Our study indicates that weekly treatment with the HGC-TAC nanomicelles reduces kidney injury resulting from lupus nephritis by preventing inflammation, fibrosis, and apoptosis. This advantage of a new therapeutic modality using kidney-targeted HGC-TAC nanocarriers may improve drug adherence and provide treatment efficacy in lupus nephritis mice.

Kidney-accumulating olmesartan-loaded nanomicelles ameliorate the organ damage in a murine model of Alport syndrome.

ACE inhibitors or angiotensin II receptor blockers (ACEi/ARBs) have been a cornerstone of the management in kidney disease, but their use is often limited by undesired systemic effects, such as symptomatic hypotension. To minimize the extra-renal effects of ACEi/ARBs, we formulated hydrophobically modified glycol chitosan (HGC) nanomicelles releasing olmesartan (HGC-Olm) that specifically accumulated in the kidney, and investigated whether kidney-specific delivery of olmesartan by HGC nanomicelles could ameliorate organ damage in Col4a3-/- mouse, a murine model of progressive chronic kidney disease mimicking human Alport syndrome. Ex vivo tracing demonstrated that intravenously injected HGC-Olm nanomicelles were specifically delivered to the kidney, with sustained release of olmesartan for more than 48 h. Contrary to the conventional delivery of olmesartan via oral route, injection of HGC-Olm nanomicelles did not alter blood pressure in Col4a3-/- mice. Immunohistochemistry revealed that HGC nanomicelles were diffusely distributed from the cortex and glomeruli to the outer medulla, sparing the inner medulla. Phenotypic analysis showed that the attenuation of kidney fibrosis in the kidney of Col4a3-/- mice by HGC-Olm nanomicelles was comparable to that noted with conventionally delivered olmesartan. Therefore, our results suggest that HGC-Olm nanomicelles could be a safe and effective alternative drug delivery system for kidney diseases.

Tumor Microenvironment-Regulating Immunosenescence-Independent Nanostimulant Synergizing with Near-Infrared Light Irradiation for Antitumor Immunity.

The combination of photothermal therapy (PTT) and toll-like receptor (TLR)-mediated immunotherapy can elicit antitumor immunity and modulate the immunosuppressive tumor microenvironment (TME). Unlike other TLRs, TLR-5 is a promising target for immune activation, as its expression is well-maintained even during immunosenescence. Here, we developed a unique tumor microenvironment-regulating immunosenescence-independent nanostimulant consisting of TLR-5 adjuvant Vibrio vulnificus flagellin B (FlaB) conjugated onto the surface to an IR 780-loaded hyaluronic acid-stearylamine (HIF) micelles. These HIF micelles induced immune-mediated cell death via PTT when irradiated with a near-infrared laser. In comparison with PTT alone, the combination of in situ-generated tumor-associated antigens produced during PTT and the immune adjuvant FlaB demonstrated enhanced vaccine-like properties and modulated the TME by suppressing immune-suppressive regulatory cells (Tregs) and increasing the fraction of CD103+ migratory dendritic cells, which are responsible for trafficking tumor antigens to draining lymph nodes (DLNs). This combinatorial strategy (i.e., applying a TLR-5 adjuvant targeted to immunosenescence-independent TLR-5 and the in situ photothermal generation of tumor-associated antigens) is a robust system for next-generation immunotherapy and could even be applied in elderly patients, thus broadening the clinical scope of immunotherapy strategies.

Glycol chitosan-based renal docking biopolymeric nanomicelles for site-specific delivery of the immunosuppressant.

In this study, we propose the use of glycol chitosan for the targeted delivery of hydrophobic drugs such as tacrolimus (TAC) towards the kidney. We synthesized a hydrophobically modified glycol chitosan (HGC) polymeric nanomicelle followed by loading TAC resulting in TAC loaded HGC nanomicelles (HGC-TAC). The HGC-TAC nanomicelles displayed spherical morphology with superior drug loading content and encapsulation efficiency. in vitro and in vivo evaluations demonstrated that HGC-TAC nanomicelles are non toxic and delivered TAC preferentially to kidney while lowering the plasma concentrations. The therapeutic effects of HGC-TAC and unencapsulated ("bare") TAC on the kidneys showed that a single intravenous administration of HGC-TAC achieved a therapeutic efficacy comparable to that obtained from daily intraperitoneal injections of TAC for 14 days without any systemic side effects. Thus, HGC-TAC nanomicelles could be effectively used for delivery of TAC towards the kidney, highlighting its potential as a safe modality for renal-targeted delivery of therapeutics.

Long circulating photoactivable nanomicelles with tumor localized activation and ROS triggered self-accelerating drug release for enhanced locoregional chemo-photodynamic therapy.

Although chemo-photodynamic therapy demonstrates promising synergetic therapeutic effect in malignant cancers, the currently available nanocarriers offer the limited capabilities for selective toxicity, drug release and tumor penetration. Herein, we developed photoactivatable nanomicelles, which are constructed by self-assembling of poly (ethylene glycol) (PEG)-stearamine (C18) conjugate (PTS) with a ROS-sensitive thioketal linker (TL) and co-loaded with doxorubicin (DOX) and photosensitizer pheophorbide A (PhA), for enhanced locoregional chemo-photodynamic therapy. Upon accumulation in tumor region, the resulting PTS nanomicelles loaded with Dox and PhA (PTS-DP) demonstrated reactive oxygen species (ROS) cascade responsive release of the DOX and PhA loaded inside. Initial intracellular release of DOX and PhA from the PTS-DP was triggered by the intrinsic presence of endogenous ROS within cancer cells. Furthermore, upon laser irradiation on the tumor region, enhanced singlet oxygen (1O2) was generated by PhA released initially in cancer cells, which in turns accelerated the cytoplasmic release of DOX through rapid dissociation of nanomicelles. The gradual elevation of local ROS level generated by light-activated PhA subsequent ROS-triggered release of DOX synergistically inhibited tumor growth and enhances the anti-tumor immunity. Findings of our study suggested that ROS-sensitive PTS nanomicelles could be a promising and innovative nanocarrier for locoregional chemo-photodynamic therapy.

Role of Immunosuppressive Microenvironment in Acquiring Immunotolerance Post-Photothermal Therapy.

BACKGROUND: Nanoparticle-mediated photothermal therapy (PTT) has been well studied as a treatment for cancer. However, the therapeutic outcome of PTT is often hindered by the penetration depth of laser light. In the tumor margin beyond the laser penetration limit, tumor recurrence often occurs, bypassing the immune response of the host. Accumulating evidence suggests the prominent role of tumor microenvironment (TME) and its interactions with the immune components contribute to an immunosuppressive milieu during the post-therapy period. Here, we explored the immunosuppressive cascade generated after PTT, which is responsible for tumor recurrence, and identified the potential targets to achieve an effective PTT period. METHODS: Here, we investigated the immunosuppressive cascade generated after PTT in a CT26 tumor bearing mouse. The liposomal system loaded with the indocyanine green (ICG) was utilized for the generation of PTT with high efficiency. Immunological factors such as cytokines and protein expressions post-therapy were investigated through enzyme-linked immunosorbent assay, flow cytometry and western blot analysis. RESULTS: Our results suggested that PTT with ICG-loaded liposomes (Lipo-ICG) was effective for the first 5 days after treatment, resulting in tumor suppression. However, an immunosuppressive and pro-inflammatory environment developed thereafter, causing the recruitment and upregulation of the immune evasion factors of heat shock protein 70, programmed death ligand 1, indoleamine-dioxygenase, interleukin-6, transforming growth factor-ß, regulatory T-cells, and myeloid-derived suppressor cells, to develop immunotolerance. CONCLUSION: Collectively, these findings have determined potential therapeutic targets to modulate the TME during PTT and achieve tumor ablation without remission.

Biopolymeric In Situ Hydrogels for Tissue Engineering and Bioimaging Applications.

BACKGROUND: Biopolymeric in situ hydrogels play a crucial role in the regenerative repair and replacement of infected or injured tissue. They possess excellent biodegradability and biocompatibility in the biological system, however only a few biopolymeric in situ hydrogels have been approved clinically. Researchers have been investigating new advancements and designs to restore tissue functions and structure, and these studies involve a composite of biometrics, cells and a combination of factors that can repair or regenerate damaged tissue. METHODS: Injectable hydrogels, cross-linking mechanisms, bioactive materials for injectable hydrogels, clinically applied injectable biopolymeric hydrogels and the bioimaging applications of hydrogels were reviewed. RESULTS: This article reviews the different types of biopolymeric injectable hydrogels, their gelation mechanisms, tissue engineering, clinical applications and their various in situ imaging techniques. CONCLUSION: The applications of bioactive injectable hydrogels and their bioimaging are a promising area in tissue engineering and regenerative medicine. There is a high demand for injectable hydrogels for in situ imaging.

IR 780-loaded hyaluronic acid micelles for enhanced tumor-targeted photothermal therapy.

In this study, we propose using IR 780-loaded, CD44-targeted hyaluronic acid-based micelles (HA-IR 780) for enhanced photothermal therapy (PTT) effects in tumors. Two kinds of HA-C18 micelles were synthesized from different C18 feed ratios with degree of substitution of 3% and 13% respectively. Three different IR 780 weight percentages were used for micelle formation with loading content of 4.6%, 7.9%, and 10.3% respectively. The IC50 value of HA-IR 780 in TC1 cells was 21.89µgmL-1 (32.81µM). Upon irradiation of the tumor site with an 808-nm laser (2Wcm-2) for 2min, the temperature in the tumor in the HA-IR 780-treated groups reached 49.9°C which exceeds the temperature threshold to induce irreversible tissue damage. Toxicity studies showed that HA-IR 780 does not cause any adverse effects in organs, including heart, liver, lungs, kidney and spleen, although it selectively caused cell damage in the tumor region upon laser irradiation. Therefore, the present study suggests that HA-IR 780 can cause selective cell death in tumor regions due to its enhanced tumor-targeting and photothermal capabilities.

Injectable hydrogels for delivering biotherapeutic molecules.

To date, numerous delivery systems based on either organic or inorganic material have been developed to achieve efficient and sustained delivery of therapeutics. Hydrogels, which are three dimensional networks of crosslinked hydrophilic polymers, have a significant role in solving the clinical and pharmacological limitations of present systems because of their biocompatibility, ease of preparation and unique physical properties such as a tunable porous nature and affinity for biological fluids. Development of an in situ forming injectable hydrogel system has allowed excellent spatial and temporal control, unlike systemically administered therapeutics. Injectable hydrogel systems can offset difficulties with conventional hydrogel-based drug delivery systems in the clinic by forming a drug/gene delivery or cell-growing depot in the body with a single injection, thereby enabling patient compliance and comfort. Carbohydrate polymers are widely used for the synthesis of injectable in situ-forming hydrogels because of ready availability, presence of modifiable functional groups, biocompatibility and other physiochemical properties. In this review, we discuss different aspects of injectable hydrogels, such as bulk hydrogels/macrogels, microgels, and nanogels derived from natural polymers, and their importance in the delivery of therapeutics such as genes, drugs, cells or other biomolecules and how these revolutionary systems can complement existing therapeutic delivery systems.

Stimuli-Regulated Smart Polymeric Systems for Gene Therapy.

The physiological condition of the human body is a composite of different environments, each with its own parameters that may differ under normal, as well as diseased conditions. These environmental conditions include factors, such as pH, temperature and enzymes that are specific to a type of cell, tissue or organ or a pathological state, such as inflammation, cancer or infection. These conditions can act as specific triggers or stimuli for the efficient release of therapeutics at their destination by overcoming many physiological and biological barriers. The efficacy of conventional treatment modalities can be enhanced, side effects decreased and patient compliance improved by using stimuli-responsive material that respond to these triggers at the target site. These stimuli or triggers can be physical, chemical or biological and can be internal or external in nature. Many smart/intelligent stimuli-responsive therapeutic gene carriers have been developed that can respond to either internal stimuli, which may be normally present, overexpressed or present in decreased levels, owing to a disease, or to stimuli that are applied externally, such as magnetic fields. This review focuses on the effects of various internal stimuli, such as temperature, pH, redox potential, enzymes, osmotic activity and other biomolecules that are present in the body, on modulating gene expression by using stimuli-regulated smart polymeric carriers.