Dexamethasone prodrug treatment prevents nephritis in lupus-prone (NZB × NZW)F1 mice without causing systemic side effects

Targeted-delivery of nanomedicine-enabled methylprednisolone to injured spinal cord promotes neuroprotection and functional recovery after acute spinal cord injury in rats

To date, no therapy has been proven to be efficacious in fully restoring neurological functions after spinal cord injury (SCI). Systemic high-dose methylprednisolone (MP) improves neurological recovery after acute SCI in both animal and human. MP therapy remains controversial due to its modest effect on functional recovery and significant adverse effects. To overcome the limitation of MP therapy, we have developed a N-(2-hydroxypropyl) methacrylamide copolymer-based MP prodrug nanomedicine (Nano-MP) that can selectively deliver MP to the SCI lesion when administered systemically in a rat model of acute SCI. Our in vivo data reveal that Nano-MP is significantly more effective than free MP in attenuating secondary injuries and neuronal apoptosis. Nano-MP is superior to free MP in improving functional recovery after acute SCI in rats. These data support Nano-MP as a promising neurotherapeutic candidate, which may provide potent neuroprotection and accelerate functional recovery with improved safety for patients with acute SCI.

Glucocorticoids-based prodrug design: Current strategies and research progress

Attributing to their broad pharmacological effects encompassing anti-inflammation, antitoxin, and immunosuppression, glucocorticoids (GCs) are extensively utilized in the clinic for the treatment of diverse diseases such as lupus erythematosus, nephritis, arthritis, ulcerative colitis, asthma, keratitis, macular edema, and leukemia. However, long-term use often causes undesirable side effects, including metabolic disorders-induced Cushing's syndrome (buffalo back, full moon face, hyperglycemia, etc.), osteoporosis, aggravated infection, psychosis, glaucoma, and cataract. These notorious side effects seriously compromise patients' quality of life, especially in patients with chronic diseases. Therefore, glucocorticoid-based advanced drug delivery systems for reducing adverse effects have received extensive attention. Among them, prodrugs have the advantages of low investment, low risk, and high success rate, making them a promising strategy. In this review, we propose the strategies for the design and summarize current research progress of glucocorticoid-based prodrugs in recent decades, including polymer-based prodrugs, dendrimer-based prodrugs, antibody-drug conjugates, peptide-drug conjugates, carbohydrate-based prodrugs, aliphatic acid-based prodrugs and so on. Besides, we also raise issues that need to be focused on during the development of glucocorticoid-based prodrugs. This review is expected to be helpful for the research and development of novel GCs and prodrugs.

Single dose thermoresponsive dexamethasone prodrug completely mitigates joint pain for 15 weeks in a murine model of osteoarthritis

In this study, we aimed to assess the analgesic efficacy of a thermoresponsive polymeric dexamethasone (Dex) prodrug (ProGel-Dex) in a mouse model of osteoarthritis (OA). At 12 weeks post model establishment, the OA mice received a single intra-articular (IA) injection of ProGel-Dex, dose-equivalent Dex, or Saline. Comparing to Saline and Dex controls, ProGel-Dex provided complete and sustained pain relief for >15 weeks according to incapacitance tests. In vivo optical imaging confirmed the continuous presence of ProGel-Dex in joints for 15 weeks post-injection. According to micro-CT analysis, ProGel-Dex treated mice had significantly lower subchondral bone thickness and medial meniscus bone volume than Dex and Saline controls. Except for a transient delay of body weight increase and slightly lower endpoint liver and spleen weights, no other adverse effect was observed after ProGel-Dex treatment. These findings support ProGel-Dex's potential as a potent and safe analgesic candidate for management of OA pain.

Biosafety of mesoporous silica nanoparticles; towards clinical translation

Mesoporous silica nanoparticles (MSNs) have attracted the attention of chemists, who have developed numerous systems for the encapsulation of a plethora of molecules, allowing the use of mesoporous silica nanoparticles for biomedical applications. MSNs have been extensively studied for their use in nanomedicine, in applications such as drug delivery, diagnosis, and bioimaging, demonstrating significant in vivo efficacy in different preclinical models. Nevertheless, for the transition of MSNs into clinical trials, it is imperative to understand the characteristics that make MSNs effective and safe. The biosafety properties of MSNs in vivo are greatly influenced by their physicochemical characteristics such as particle shape, size, surface modification, and silica framework. In this review, we compile the most relevant and recent progress in the literature up to the present by analyzing the contributions on biodistribution, biodegradability, and clearance of MSNs. Furthermore, the ongoing clinical trials and the potential challenges related to the administration of silica materials for advanced therapeutics are discussed. This approach aims to provide a solid overview of the state-of-the-art in this field and to encourage the translation of MSNs to the clinic.

Macromolecular Dexamethasone Prodrug Ameliorates Neuroinflammation and Prevents Bone Loss Associated with Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the leading causes of death and disability among children and young adults in the United States. In this manuscript, we assessed the utility of an N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-based dexamethasone (Dex) prodrug (P-Dex) in the treatment of TBI. Using a controlled cortical impact TBI mouse model, P-Dex was found to passively target and sustain at the traumatic/inflammatory brain tissue for over 14 days after systemic administration. The histological evidence supports P-Dex's therapeutic potential in ameliorating neuroinflammation and mitigating neurodegeneration. Behaviorally, the P-Dex-treated animals showed statistically significant improvement in balance recovery. A trend of neurological severity score improvement at the early time point post-TBI was also noted but did not achieve statistical significance. While probing the potential glucocorticoid side effects that may associate with P-Dex treatment, we discovered that the TBI mice develop osteopenia. Interestingly, the P-Dex-treated TBI mice demonstrated higher bone mineral density and better bone microarchitecture parameters when compared to free Dex and the saline control, revealing the osteoprotective effect of P-Dex in addition to its neuronal protection benefits post-TBI.

Polymeric dexamethasone prodrugs attenuate lupus nephritis in MRL/lpr mice with reduced glucocorticoid toxicity

Due to their potent immunosuppressive and anti-inflammatory effects, glucocorticoids (GCs) are the most widely used medications in treating lupus nephritis (LN). Long-term use of GCs, however, is associated with numerous off-target adverse effects. To reduce GCs' adverse effects, we previously developed two polymeric dexamethasone prodrug nanomedicines: N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-based dexamethasone prodrug (P-Dex), and micelle-forming polyethylene glycol (PEG)-based dexamethasone prodrug (ZSJ-0228). Both P-Dex and ZSJ-0228 provided sustained amelioration of LN in lupus-prone NZB/W F1 mice with reduced GC-associated adverse effects. Here, we have extended our investigation to the MRL/lpr mouse model of LN. Compared to dose equivalent daily dexamethasone sodium phosphate (Dex) treatment, monthly P-Dex or ZSJ-0228 treatments were more effective in reducing proteinuria and extending the lifespan of MRL/lpr mice. Unlike the daily Dex treatment, ZSJ-0228 was not associated with measurable GC-associated adverse effects. In contrast, adrenal gland atrophy was observed in P-Dex treated mice.

Inflammation-targeted sialic acid-dexamethasone conjugates for reducing the side effects of glucocorticoids

As a potent glucocorticoid drug (GCs), Dexamethasone (Dex) is widely used clinically for the treatment of inflammatory diseases. However, such side effects as Cushing's syndrome and osteoporosis caused severe distress to patients. Herein, a sialic acid (SA)-modified dexamethasone conjugate (Dex-SA) was synthesized successfully to reduce side effects by targeting inflammatory diseases. The solubility of Dex-SA in water reached 58 times that of Dex, which meets the need for intravenous administration. The excellent stability of Dex-SA in plasma also laid a foundation for targeting disease sites. According to cellular uptake and biodistribution experiments, Dex-SA was more readily to be taken up by inflammatory cells and accumulated in diseased kidneys compared to Dex, which is attributed to the interaction of SA with E-selectin receptors overexpressed on the surface of inflammatory vascular endothelial cells. Besides, the pharmacodynamics studies of acute kidney injury showed that Dex-SA and Dex could produce comparable therapeutic effects. More importantly, Dex-SA was found to significantly reduce Dex-related side effects, as measured by blood glucose, red blood cells and immune cells, etc. At last, molecular docking results were obtained to confirm that Dex-SA could enter the cells by binding specifically with the E-selectin receptor, for combination with glucocorticoid receptors in the cytoplasm to exert pharmacological effects. Our study is expected to contribute a new strategy to the safe and effective targeting treatment of inflammatory diseases.

Co-Delivery of Dexamethasone and Captopril by α8 Integrin Antibodies Modified Liposome-PLGA Nanoparticle Hybrids for Targeted Anti-Inflammatory/Anti-Fibrosis Therapy of Glomerulonephritis

Purpose

Mesangial cells-mediated glomerulonephritis refers to a category of immunologically mediated glomerular injuries characterized by infiltration of circulating inflammatory cells, proliferation of mesangial cells, and the common pathological manifestation to the later stage is renal fibrosis, accompanied by excessive accumulation of extracellular matrix (ECM). Treatment regimens include glucocorticoids and immunosuppressive agents, but their off-target distribution causes severe systemic toxicity. Hence, specific co-delivery of “anti-inflammatory/anti-fibrosis” drugs to the glomerular mesangial cell (MC) region is expected to produce better therapeutic effects.

Methods

A novel kidney-targeted nanocarrier drug delivery system targeting MCs was constructed using passive targeting resulting from the difference in pore size between the glomerular endothelial layer and the basement membrane, and active targeting based on the specific binding of antibodies and antigens. Specifically, a liposome-nanoparticle hybrid (PLGA-LNHy) was formed by coating the surface of PLGA nanoparticles (NPs) with a phospholipid bilayer, and then PLGA-LNHy was co-modified with PEG and α8 integrin antibodies to obtain PLGA immunoliposomes (PLGA-ILs).

Results

The results showed that the obtained NPs had a core-shell structure, uniform and suitable particle size (119.1 ± 2.31 nm), low cytotoxicity, and good mesangial cell-entry ability, which can successfully accumulate in the glomerular MC region. Both dexamethasone (DXMS) and captopril (CAP) were loaded onto PLGA-ILs with a drug loading of 10.22 ± 1.00% for DXMS and 6.37 ± 0.25% for CAP (DXMS/CAP@PLGA-ILs). In vivo pharmacodynamics showed that DXMS/CAP@PLGA-ILs can effectively improve the pathological changes in the mesangial area and positive expression of proliferating cell nuclear antigen (PCNA) in glomeruli as well as reduce the expression of inflammatory factors, fibrotic factors and reactive oxygen species (ROS). Thus, renal inflammation and fibrosis were relieved.

Conclusion

We have provided a strategy to increase nanoparticle accumulation in MCs with the potential to implement regulatory effects of anti-inflammatory and anti-fibrosis in glomerulonephritis (GN).

Targeted Delivery of Chloroquine to Antigen-Presenting Cells Enhances Inhibition of the Type I Interferon Response

Systemic lupus erythematosus (SLE) causes damaging inflammation in multiple organs via the accumulation of immune complexes. These complexes activate plasmacytoid dendritic cells (pDCs) via toll-like receptors (TLRs), contributing to disease pathogenesis by driving the secretion of inflammatory type I interferons (IFNs). Antimalarial drugs, such as chloroquine (CQ), are TLR antagonists used to alleviate inflammation in SLE. However, they require ∼3 months of continuous use before achieving therapeutic efficacy and can accumulate in the retinal pigment epithelium with chronic use, resulting in retinopathy. We hypothesized that poly(ethylene glycol)-b-poly(propylene sulfide) filamentous nanocarriers, filomicelles (FMs), could directly deliver CQ to pDCs via passive, morphology-based targeting to concentrate drug delivery to specific immune cells, improve drug activity by increased inhibition of type I IFN, and enhance efficacy per dose. Healthy human peripheral blood mononuclear cells were treated with soluble CQ or CQ-loaded FMs, stimulated with TLR agonists or SLE patient sera, and type I IFN secretion was quantified via multi-subtype IFN-α ELISA and MX1 gene expression using real-time reverse transcription-quantitative polymerase chain reaction. Our results showed that 50 μg CQ/mg FM decreased MX1 expression and IFN-α production after TLR activation with either synthetic nucleic acid agonists or immune complex-rich sera from SLE patients. Cellular uptake and biodistribution studies showed that FMs preferentially accumulate in human pDCs and monocytes in vitro and in tissues frequently damaged in SLE patients (i.e., kidneys), while sparing the eye in vivo. These results showed that nanocarrier morphology enables drug delivery, and CQ-FMs may be equally effective and more targeted than soluble CQ at inhibiting SLE-relevant pathways.

Thermoresponsive polymeric dexamethasone prodrug for arthritis pain

Intra-articular (IA) glucocorticoids (GC) are commonly used for clinical management of both osteoarthritis and rheumatoid arthritis, but their efficacy is limited by the relatively short duration of action and associated side effects. To provide sustained efficacy and to improve the safety of GCs, we previously developed a N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-based dexamethasone (Dex) prodrug. Serendipitously, we discovered that, by increasing the Dex content of the prodrug to unusually high levels, the aqueous solution of the polymeric prodrug becomes thermoresponsive, transitioning from a free-flowing liquid at 4 °C to a hydrogel at 30 °C or greater. Upon IA injection, the prodrug solution forms a hydrogel (ProGel-Dex) that is retained in the joint for more than 1 month, where it undergoes gradual dissolution, releasing the water-soluble polymeric prodrug. The released prodrug is swiftly internalized and intracellularly processed by phagocytic synoviocytes to release free Dex, resulting in sustained amelioration of joint inflammation and pain in rodent models of inflammatory arthritis and osteoarthritis. The low molecular weight (6.8 kDa) of the ProGel-Dex ensures rapid renal clearance once it escapes the joint, limiting systemic GC exposure and risk of potential off-target side effects. The present study illustrates the translational potential of ProGel-Dex as a potent opioid-sparing, locally delivered adjuvant analgesic for sustained clinical management of arthritis pain and inflammation. Importantly, the observed thermoresponsive properties of the prodrug establishes ProGel as a platform technology for the local delivery of a broad spectrum of therapeutic agents to treat a diverse array of pathological conditions.

Assessing Lupus-Like Disease in Murine Model Systems

Systemic Lupus Erythematosus (SLE) is a complex and heterogenous autoimmune disease, where genetics, immunology, and environmental factors all play a role. Murine models have contributed critical information on mechanisms of disease and prospective therapeutics. The key features that have been used to study the disease include the development of anti-nuclear autoantibodies (ANAs), splenomegaly, and kidney disease. The loss of tolerance and subsequent autoimmune features, and the progression to severe disease, are all dependent on immune dysregulation. In this article, we will describe the methods used to evaluate the underlying immunological features of the disease, as a more sensitive strategy to understand the disease itself and the mechanisms of potential novel therapeutics. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: End study protocols for tissue harvesting Basic Protocol 2: End study protocols for tissue processing Basic Protocol 3: Immunophenotyping using flow cytometry protocols Support Protocol: Tissue processing for cold storage Basic Protocol 4: Additional tissue processing for later analyses Basic Protocol 5: Analysis of serum auto-antibodies by ELISAs (ANAs, snRNP, and dsDNA).

Preclinical Dose-Escalation Study of ZSJ-0228, a Polymeric Dexamethasone Prodrug, in the Treatment of Murine Lupus Nephritis

Glucocorticoids (GCs) are widely used in the clinical management of lupus nephritis (LN). Their long-term use, however, is associated with the risk of significant systemic side effects. We have developed a poly(ethylene glycol) (PEG)-based dexamethasone (Dex) prodrug (i.e., ZSJ-0228) and in a previous study, demonstrated its potential therapeutic efficacy in mice with established LN, while avoiding systemic GC-associated toxicity. In the present study, we have employed a dose-escalation design to establish the optimal dose-response relationships for ZSJ-0228 in treating LN and further investigated the safety of ZSJ-0228 in lupus-prone NZB/W F1 mice with established nephritis. ZSJ-0228 was intravenously (i.v.) administered monthly at four levels: 0.5 (L1), 1.0 (L2), 3.0 (L3), and 8.0 (L4) mg/kg/day Dex equivalent. For controls, mice were treated with i.v. saline every 4 weeks. In addition, a group of mice received intraperitoneal injections (i.p.) of Dex every day or i.v. injections of Dex every four weeks. Treatment of mice with LN with ZSJ-0228 dosed at L1 resulted in the resolution of proteinuria in 14% of the mice. Mice treated with ZSJ-0228 dosed at L2 and L3 levels resulted in the resolution of proteinuria in ∼60% of the mice in both groups. Treatment with ZSJ-0228 dosed at L4 resulted in the resolution of proteinuria in 30% of the mice. The reduction and/or resolution of the proteinuria, improvement in renal histological scores, and survival data indicate that the most effective dose range for ZSJ-0228 in treating LN in NZB/W F1 mice is between 1.0 and 3.0 mg/kg/day Dex equivalent. Typical GC-associated side effects (e.g., osteopenia, adrenal glands atrophy, etc.) were not observed in any of the ZSJ-0228 treatment groups, confirming its excellent safety profile.

Dexamethasone Conjugates: Synthetic Approaches and Medical Prospects

Dexamethasone (DEX) is the most commonly prescribed glucocorticoid (GC) and has a wide spectrum of pharmacological activity. However, steroid drugs like DEX can have severe side effects on non-target organs. One strategy to reduce these side effects is to develop targeted systems with the controlled release by conjugation to polymeric carriers. This review describes the methods available for the synthesis of DEX conjugates (carbodiimide chemistry, solid-phase synthesis, reversible addition fragmentation-chain transfer [RAFT] polymerization, click reactions, and 2-iminothiolane chemistry) and perspectives for their medical application as GC drug or gene delivery systems for anti-tumor therapy. Additionally, the review focuses on the development of DEX conjugates with different physical-chemical properties as successful delivery systems in the target organs such as eye, joint, kidney, and others. Finally, polymer conjugates with improved transfection activity in which DEX is used as a vector for gene delivery in the cell nucleus have been described.

In Vitro to In Vivo Concordance of Toxicity Using the Human Proximal Tubule Cell Line HK-2

The renal proximal tubule cell line, human kidney 2 (HK-2), recapitulates many of the functional cellular and molecular characteristics of differentiated primary proximal tubule cells. These features include anchorage dependence, gluconeogenesis capability, and sodium-dependent sugar transport. In order to ascertain how well HK-2 cells can reliably reveal the toxicological profile of compounds having a potential to cause proximal tubule injury in vivo, we sought to evaluate the effects of known proximal tubule toxicants using the HK-2 cell line. We selected 20 pure nephrotoxic compounds that included chemotherapeutic drugs, antibiotics, and heavy metal-containing compounds and evaluated their ability to induce HK-2 cell injury relative to 10 innocuous pure compounds or cell culture media alone. We performed a comprehensive set of in vitro cellular toxicological assays to evaluate cell viability, oxidative stress, mitochondrial integrity, and a specific biomarker of renal injury, Kidney Injury Molecule 1. For each of our selected compounds, we were able to establish a reproducible profile of toxicological outcomes. We compared our results to those described in peer-reviewed publications to understand how well the HK-2 cellular model agrees with overall in vivo rat or human toxicological outcomes. This study begins to address the question of how well in vitro data generated with HK-2 cells can mirror in vivo animal and human outcomes.

Head-to-head comparative pharmacokinetic and biodistribution (PK/BD) study of two dexamethasone prodrug nanomedicines on lupus-prone NZB/WF1 mice

HPMA copolymer-based dexamethasone prodrug (P-Dex) and PEG-based dexamethasone prodrug (PEG-Dex, ZSJ-0228) were previously found to passively target the inflamed kidney and provide potent and sustained resolution of nephritis in NZB/WF1 lupus-prone mice. While both prodrug nanomedicines effectively ameliorate lupus nephritis, they have demonstrated distinctively different safety profiles. To explore the underlining mechanisms of these differences, we conducted a head-to-head comparative PK/BD study of P-Dex and PEG-Dex on NZB/WF1 mice. Overall, the systemic organ/tissue exposures to P-Dex and Dex released from P-Dex were found to be significantly higher than those of PEG-Dex. The high prodrug concentrations were sustained in kidney for only 24 h, which cannot explain their lasting therapeutic efficacy (>1 month). P-Dex showed sustained presence in liver, spleen and adrenal gland, while the presence of PEG-Dex in these organs was transient. This difference in PK/BD profiles may explain PEG-Dex' superior safety than P-Dex.

Sialic acid-modified dexamethasone lipid calcium phosphate gel core nanoparticles for target treatment of kidney injury

Acute kidney injury (AKI) is a common clinical disease with high morbidity and mortality. Glucocorticoids are drugs that effectively relieve AKI, but the systemic side effects of long-term use limit their use. Herein, we constructed sialic acid-modified dexamethasone sodium phosphate (Dsp)-loaded lipid calcium phosphate gel core nanoparticles (SA-NPs) for the targeted treatment of ischemia-reperfusion (I/R)-induced AKI to improve efficacy and reduce side effects. The obtained nanoparticles could effectively encapsulate Dsp with 66.8% encapsulation efficiency and 4.56% (w/w) drug content. In vitro release indicates that the nanoparticles have a certain sustained release effect and have the characteristics of acid-sensitive release. And SA-NPs significantly increased the cellular uptake and kidney accumulation respectively through the combination of SA and E-selectin receptors overexpressed in inflamed vascular endothelial cells. Besides, the in vivo pharmacokinetic studies showed that Dsp-loaded SA-NPs significantly increased the residence time in the body and their plasma half-life was 1.7 times that of free Dsp. SA-NPs significantly improved the renal function, decreased the level of pro-inflammatory factors, and adjusted the oxidative stress factors and apoptotic proteins compared to free Dsp solution in pharmacodynamic studies. Moreover, little negative effects on blood glucose and bone mineral density were observed. Our study might provide a new strategy for the safe and effective targeting treatment of AKI or other related inflammatory diseases.

Genetically Engineered Human Kidney Cells for Real-Time Cytotoxicity Testing In Vitro

Classic toxicology studies often utilize in vivo animal models. Newer approaches employing in vitro organ-specific cellular models have been developed in recent years to help accelerate the speed and reduce the cost of traditional toxicology testing. Toward the goal of supporting in vitro cellular model research with a regulatory application in mind, we have developed a 'designer' human kidney cell line called HK2-Vi that can fluorescently measure the cytotoxicity of potential toxins on proximal tubule cell viability in a direct exposure in vitro model. HK2-Vi was designed to be a reagent-less kinetic assay that can yield data on short- or long-term cell viability after toxin exposure. To generate HK2-Vi, we used monocistronic lentiviral transduction methods to genetically engineer a human kidney cell line called HK-2 to stably co-express two transgenes. The first is Perceval HR, which encodes a fluorescent biosensor of both cytosolic ATP and ADP and the second is pHRed, which encodes a biosensor of cytosolic pH. Relative levels of cellular ATP and ADP effectively serve as a reliable and robust indicator of cell viability. Because the fluorescence Perceval HR is pH-dependent, we co-expressed the pHRed genetic biosensor to correct for variations in pH if necessary. Heterogenous populations of transduced renal cells were enriched by flow cytometry before monoclonal cellular populations were isolated by cell culture methods. A single clonal population of co-transduced cells expressing both Perceval HR and pHRed was selected to be HK2-Vi. This established cell line can now serve as a tool for in vitro toxicology testing and the methods described herein serve as a model for developing designer cell lines derived from other organs.

Ca2+ signalling plays a role in celastrol-mediated suppression of synovial fibroblasts of rheumatoid arthritis patients and experimental arthritis in rats

Background and Purpose

Celastrol exhibits anti‐arthritic effects in rheumatoid arthritis (RA), but the role of celastrol‐mediated Ca²⁺ mobilization in treatment of RA remains undefined. Here, we describe a regulatory role for celastrol‐induced Ca²⁺ signalling in synovial fibroblasts of RA patients and adjuvant‐induced arthritis (AIA) in rats.

Experimental Approach

We used computational docking, Ca²⁺ dynamics and functional assays to study the sarcoplasmic/endoplasmic reticulum Ca²⁺ ATPase pump (SERCA). In rheumatoid arthritis synovial fibroblasts (RASFs)/rheumatoid arthritis fibroblast‐like synoviocytes (RAFLS), mechanisms of Ca²⁺‐mediated autophagy were analysed by histological, immunohistochemical and flow cytometric techniques. Anti‐arthritic effects of celastrol, autophagy induction, and growth rate of synovial fibroblasts in AIA rats were monitored by microCT and immunofluorescence staining. mRNA from joint tissues of AIA rats was isolated for transcriptional analysis of inflammatory genes, using siRNA methods to study calmodulin, calpains, and calcineurin.

Key Results

Celastrol inhibited SERCA to induce autophagy‐dependent cytotoxicity in RASFs/RAFLS via Ca²⁺/calmodulin‐dependent kinase kinase‐β–AMP‐activated protein kinase–mTOR pathway and repressed arthritis symptoms in AIA rats. BAPTA/AM hampered the in vitro and in vivo effectiveness of celastrol. Inflammatory‐ and autoimmunity‐associated genes down‐regulated by celastrol in joint tissues of AIA rat were restored by BAPTA/AM. Knockdown of calmodulin, calpains, and calcineurin in RAFLS confirmed the role of Ca²⁺ in celastrol‐regulated gene expression.

Conclusion and Implications

Celastrol triggered Ca²⁺ signalling to induce autophagic cell death in RASFs/RAFLS and ameliorated arthritis in AIA rats mediated by calcium‐dependent/‐binding proteins facilitating the exploitation of anti‐arthritic drugs based on manipulation of Ca²⁺ signalling.

Synthesis of budesonide conjugates and their anti-inflammatory effects: a preliminary study

Purpose

Budesonide (Bud) is a nonhalogenated glucocorticoid with high anti-inflammatory potency and low systemic side effects. However, the poor water solubility of Bud affects its dissolution and release behavior, thus influencing its anti-inflammatory effect. This study was aimed at synthesizing and evaluating novel conjugates of Bud, hoping to increase the anti-inflammatory activity of Bud by improving its water solubility.

Materials and methods

Seven novel Bud conjugates (3a-3g) were designed and synthesized in this study. Besides, the equilibrium solubility, cell viability, in vitro and in vivo anti-inflammatory activity, and the hydrolysis behavior of the conjugates in different pH solutions, rat and human plasma, and rat lung homogenate were studied in detail.

Results

As compared to Bud, the equilibrium solubility of 3a, 3c, and 3e was significantly increased; 3a, 3b, and 3c significantly inhibited the interleukin-6 production in lipopolysaccharide-induced A549 cells; 3a and 3e could significantly decrease the xylene-induced ear edema; and 3a and 3c were gradually and slowly hydrolyzed into Bud in the alveolar fluid and lung homogenate and broken down quickly in plasma.

Conclusion

The amino acid ester compounds budesonide-21-glycine ester (3a) and budesonide-21-alanine ester (3c) were selected as potential conjugates of Bud. This study would provide a theoretical and an experimental basis for the in vivo process of glucocorticoids and the treatment of inflammatory diseases.

A Macromolecular Janus Kinase (JAK) Inhibitor Prodrug Effectively Ameliorates Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice

BACKGROUND

Tofacitinib (Tofa) has been approved for moderately to severely active ulcerative colitis (UC). To improve its therapeutic efficacy and limit dose-dependent toxicity, we developed a macromolecular prodrug of Tofa (P-Tofa). If the prodrug design improves the potency and duration of Tofa therapy, it would widen its therapeutic window, potentially leading to improved safety and better clinical management of UC.

METHODS

P-Tofa was synthesized by conjugating Tofa to N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer via a cleavable carbamate linker. DSS-induced UC mouse model were treated with Tofa (daily oral gavage, from day 8), P-Tofa (single intravenous administration on day 8, dose equivalent to Tofa treatment) and saline. Healthy mice were used as a positive control. The therapeutic efficacy was evaluated using disease activity index (DAI), endoscopic score and end-point histology. The optical imaging, immunohistochemistry and flow cytometry were used to understand P-Tofa's working mechanism.

RESULTS

DAI results suggested that a single dose P-Tofa treatment was more efficacious than dose equivalent daily Tofa treatment. Endoscopic evaluation and histology analyses confirmed that while both P-Tofa and Tofa protected the colon, P-Tofa treated group was observed with better colon integrity with less tissue damage. Optical imaging, flow cytometry and immunohistochemistry results showed that P-Tofa passively targeted the inflamed colon and being retained via cellular sequestration.

CONCLUSIONS

Single intravenous administration of P-Tofa was more effective than dose equivalent daily oral Tofa gavage in ameliorating DSS-induced colitis. This observed superior therapeutic efficacy may be attributed to P-Tofa's passive targeting to and retention by the inflamed colon.

Micelle-Forming Dexamethasone Prodrug Attenuates Nephritis in Lupus-Prone Mice without Apparent Glucocorticoid Side Effects

Nephritis is one of the major complications of systemic lupus erythematosus. While glucocorticoids (GCs) are frequently used as the first-line treatment for lupus nephritis (LN), long-term GC usage is often complicated by severe adverse effects. To address this challenge, we have developed a polyethylene glycol-based macromolecular prodrug (ZSJ-0228) of dexamethasone, which self-assembles into micelles in aqueous media. When compared to the dose equivalent daily dexamethasone 21-phosphate disodium (Dex) treatment, monthly intravenous administration of ZSJ-0228 for two months significantly improved the survival of lupus-prone NZB/W F1 mice and was much more effective in normalizing proteinuria, with clear histological evidence of nephritis resolution. Different from the dose equivalent daily Dex treatment, monthly ZSJ-0228 administration has no impact on the serum anti-double-stranded DNA (anti-dsDNA) antibody level but can significantly reduce renal immune complex deposition. No significant systemic toxicities of GCs ( e. g., total IgG reduction, adrenal gland atrophy, and osteopenia) were found to be associated with ZSJ-0228 treatment. In vivo imaging and flow cytometry studies revealed that the fluorescent-labeled ZSJ-0228 primarily distributed to the inflamed kidney after systemic administration, with renal myeloid cells and proximal tubular epithelial cells mainly responsible for its kidney retention. Collectively, these data suggest that the ZSJ-0228's potent local anti-inflammatory/immunosuppressive effects and improved safety may be attributed to its nephrotropicity and cellular sequestration at the inflamed kidney tissues. Pending further optimization, it may be developed into an effective and safe therapy for improved clinical management of LN.

Development of a Janus Kinase Inhibitor Prodrug for the Treatment of Rheumatoid Arthritis

While highly efficacious in treating rheumatoid arthritis (RA), the approved Janus kinase (JAK) inhibitor, Tofacitinib (Tofa, CP-690 550), has dose-dependent toxicities that limit its clinical application. In this study, we have examined whether a prodrug design that targets arthritic joints would enhance Tofa's therapeutic efficacy, which may provide an opportunity for future development of safer Tofa dosing regimens. A prodrug of Tofa (P-Tofa) was synthesized by conjugating the drug to the N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer via an acid cleavable carbamate linker. The therapeutic efficacy of a single dose of P-Tofa was compared to the dose-equivalent daily oral administration of Tofa in an adjuvant-induced arthritis (AA) rat model. Saline treated AA rats and age-matched healthy rats were used as controls. Observational analyses support the superior and sustained efficacy of a single dose P-Tofa treatment compared to the dose-equivalent daily Tofa administration in ameliorating joint inflammation. Micro-CT and histological analyses demonstrated that the P-Tofa treatment provided a structural preservation of the joints better than that of the dose-equivalent Tofa. Optical imaging, immunohistochemistry, and fluorescence-activated cell sorting analyses attribute P-Tofa's superior therapeutic efficacy to its passive targeting to arthritic joints and inflammatory cell-mediated sequestration. In vitro cell culture studies reveal that the P-Tofa treatment produced sustained the inhibition of JAK/STAT6 signaling in IL-4-treated murine bone marrow macrophages, consistent with a gradual subcellular release of Tofa. Collectively, a HPMA-based nanoscale prodrug of P-Tofa has the potential to enhance the therapeutic efficacy and widen the therapeutic window of Tofa therapy in RA.

Beneficial effect of magnolol on lupus nephritis in MRL/lpr mice by attenuating the NLRP3 inflammasome and NF‑κB signaling pathway: A mechanistic analysis

Lupus nephritis (LN) is a common complication of systemic lupus erythematosus. The present study aimed to elucidate the protective effect of magnolol (MG) on the progression of LN, via inhibition of key signaling pathways. The results of the present study demonstrated that administration of MG caused inhibition of the activation of NACHT, LRR and PYD domains‑containing protein 3 and interleukin‑1β production. Histopathological analysis confirmed that the vehicle‑treated group exhibited characteristic glomerular disease, which was observed to be suppressed following the administration of MG; a marked decrease in glomerular and vascular lesions was observed compared with the vehicle control. This decrease was further demonstrated through analysis of kidney sections. The expression level of cell surface glycoprotein F4/80 was demonstrated to be markedly decreased in the MG‑treated mice compared with the vehicle control group. The MG‑treated mice exhibited a marked decrease in serum and renal tumor necrosis factor‑α expression levels.

Synthetic Macromolecular Antibiotic Platform for Inhalable Therapy against Aerosolized Intracellular Alveolar Infections

Lung-based intracellular bacterial infections remain one of the most challenging infectious disease settings. For example, the current standard for treating Franciscella tularensis pneumonia (tularemia) relies on administration of oral or intravenous antibiotics that poorly achieve and sustain pulmonary drug bioavailability. Inhalable antibiotic formulations are approved and in clinical development for upper respiratory infections, but sustained drug dosing from inhaled antibiotics against alveolar intracellular infections remains a current unmet need. To provide an extended therapy against alveolar intracellular infections, we have developed a macromolecular therapeutic platform that provides sustained local delivery of ciprofloxacin with controlled dosing profiles. Synthesized using RAFT polymerization, these macromolecular prodrugs characteristically have high drug loading (16-17 wt % drug), tunable hydrolysis kinetics mediated by drug linkage chemistry (slow-releasing alkyllic vs fast-releasing phenolic esters), and, in general, represent new fully synthetic nanotherapeutics with streamlined manufacturing profiles. In aerosolized and completely lethal F.t. novicida mouse challenge models, the fast-releasing ciprofloxacin macromolecular prodrug provided high cure efficiencies (75% survival rate under therapeutic treatment), and the importance of release kinetics was demonstrated by the inactivity of the similar but slow-releasing prodrug system. Pharmacokinetics and biodistribution studies further demonstrated that the efficacious fast-releasing prodrug retained drug dosing in the lung above the MIC over a 48 h period with corresponding C_max/MIC and AUC_0-24h/MIC ratios being greater than 10 and 125, respectively; the thresholds for optimal bactericidal efficacy. These findings identify the macromolecular prodrug platform as a potential therapeutic system to better treat alveolar intracellular infections such as F. tularensis, where positive patient outcomes require tailored antibiotic pharmacokinetic and treatment profiles.

Pharmacokinetic and Biodistribution Studies of HPMA Copolymer Conjugates in an Aseptic Implant Loosening Mouse Model

N-(2-Hydroxypropyl) methacrylamide (HPMA) copolymers were previously found to represent a versatile delivery platform for the early detection and intervention of orthopedic implant loosening. In this article, we evaluated the impact of different structural parameters of the HPMA copolymeric system (e.g., molecular weight (MW), drug content) to its pharmacokinetics and biodistribution (PK/BD) profile. Using ¹²⁵I, Alexa Fluor 488, and IRDye 800 CW-labeled HPMA copolymer-dexamethasone (P-Dex) conjugates with different MW and dexamethasone (Dex) contents, we found the MW to be the predominant impact factor on the PK/BD profiles of P-Dex, with Dex content as a secondary impact factor. In gamma counter-based PK/BD studies, increased MW of P-Dex reduced elimination, leading to lower clearance, longer half-life, and higher systemic exposure (AUC and MRT). In the semiquantitative live animal optical imaging evaluation, the distribution of P-Dex to the peri-implant inflammatory lesion increased when MW was increased. This result was further confirmed by FACS analyses of cells isolated from peri-implant regions after systemic administration of Alexa Fluor 488-labeled P-Dex. Since the in vitro cell culture study suggested that the internalization of P-Dex by macrophages is generally independent of P-Dex's MW and Dex content, the impact of the MW and Dex content on its PK/BD profile was most likely exerted at physiological and pathophysiological levels rather than at the cellular level. In both gamma counter-based PK/BD analyses and semiquantitative optical imaging analyses, P-Dex with 6 wt % Dex content showed fast clearance. Dynamic light scattering analyses unexpectedly revealed significant molecular aggregation of P-Dex at this Dex content level. The underlining mechanisms of the aggregation and fast in vivo clearance of the P-Dex warrant further investigation.

Losartan and Dexamethasone may inhibit chemotaxis to reduce the infiltration of Th22 cells in IgA nephropathy

Angiotensin II is considered a major profibrotic factor that is involved in tissue remodeling processes, as the inhibition of Angiotensin II can halt renal inflammatory processes. Dexamethasone, an important anti-inflammatory and immunosuppressive agent, has been widely used to treat renal disease for decades. In this study, we explored the frequency of Th22 cells in a mouse model of IgA nephropathy and compared the possible effects of Losartan and Dexamethasone on Th22 cells. The experiments were performed using 6-week-old BALB/c female mice in an established IgA nephropathy model. The mice were randomly separated into 4 groups, which were administered Losartan (30mg/kg/d) or Dexamethasone (10mg/kg/d) and subjected to IgA nephropathy or the normal control treatment for 1month. The frequency of Th22 cells was measured via flow cytometry, and the relative pathological changes in renal morphology were measured with different pathological staining methods. Immunohistochemistry was performed to verify the expression of CCR10 and CCL27, which is specialized receptor on Th22 cells and its corresponding chemokine, respectively. The concentrations of CCL27 and IL-22 in renal tissue homogenates and sera were detected using ELISAs. Losartan and Dexamethasone differentially decreased the frequency of Th22 cells after 1month, and mesangial cell proliferation was also improved. Moreover, the expression of CCR10, CCL27 and IL-22 was reduced by treatment with either drug. However, significant differences between Losartan and Dexamethasone were not observed. Based on these findings, Losartan and Dexamethasone may suppress inflammatory responses by inhibiting the chemotaxis of Th22 cells in IgA nephropathy.

The Evaluation of Therapeutic Efficacy and Safety Profile of Simvastatin Prodrug Micelles in a Closed Fracture Mouse Model

PURPOSE

To evaluate the therapeutic efficiency of a micellar prodrug formulation of simvastatin (SIM/SIM-mPEG) and explore its safety in a closed femoral fracture mouse model.

METHODS

The amphiphilic macromolecular prodrug of simvastatin (SIM-mPEG) was synthesized and formulated together with free simvastatin into micelles. It was also labeled with a near infrared dye for in vivo imaging purpose. A closed femoral fracture mouse model was established using a three-points bending device. The mice with established closed femoral fractures were treated with SIM/SIM-mPEG micelles, using free simvastatin and saline as controls. The therapeutic efficacy of the micelles was evaluated using a high-resolution micro-CT. Serum biochemistry and histology analyses were performed to explore the potential toxicity of the micelle formulation.

RESULTS

Near Infrared Fluorescence (NIRF) imaging confirmed the passive targeting of SIM/SIM-mPEG micelles to the bone lesion of the mice with closed femoral fractures. The micelle was found to promote fracture healing with an excellent safety profile. In addition, the accelerated healing of the femoral fracture also helped to prevent disuse-associated ipsilateral tibia bone loss.

CONCLUSION

SIM/SIM-mPEG micelles were found to be an effective and safe treatment for closed femoral fracture repair in mice. The evidence obtained in this study suggests that it may have the potential to be translated into a novel therapy for clinical management of skeletal fractures and non-union.

Macromolecular glucocorticoid prodrug improves the treatment of dextran sulfate sodium-induced mice ulcerative colitis

A macromolecular prodrug (P-Dex) of dexamethasone (Dex) was developed to improve the treatment of inflammatory bowel disease (IBD). Colonic inflammation was induced by feeding mice with dextran sulfate sodium. Mice were treated with daily i.p. injection of free Dex or single i.v. injection of P-Dex, PBS or free polymer. Both P-Dex and free Dex could lower disease activity index and histology scores when compared to the controls. A single injection of P-Dex with 1/4 equivalent Dex dose had a better therapeutic effect than daily free Dex treatment. Mechanism study found that P-Dex could target the inflamed colon, and be retained by epithelial cells and local inflammatory infiltrates, suggesting that the improved efficacy of P-Dex may be attributed to its inflammation targeting, subcellular processing and activation. Collectively, these data support our hypothesis that the development of macromolecular prodrug of glucocorticoid may have the potential to improve the clinical management of IBD.

Simvastatin prodrug micelles target fracture and improve healing

Simvastatin (SIM), a widely used anti-lipidemic drug, has been identified as a bone anabolic agent. Its poor water solubility and the lack of distribution to the skeleton, however, have limited its application in the treatment of bone metabolic diseases. In this study, an amphiphilic macromolecular prodrug of SIM was designed and synthesized to overcome these limitations. The polyethylene glycol (PEG)-based prodrug can spontaneously self-assemble to form micelles. The use of SIM trimer as the prodrug's hydrophobic segment allows easy encapsulation of additional free SIM. The in vitro studies showed that SIM/SIM-mPEG micelles were internalized by MC3T3 cells via lysosomal trafficking and consistently induced expression of both BMP2 and DKK1 mRNA, suggesting that the prodrug micelle retains the biological functions of SIM. After systemic administration, optical imaging suggests that the micelles would passively target to bone fracture sites associated with hematoma and inflammation. Furthermore, flow cytometry study revealed that SIM/SIM-mPEG micelles had preferred cellular uptake by inflammatory and resident cells within the fracture callus tissue. The treatment study using a mouse osteotomy model validated the micelles' therapeutic efficacy in promoting bone fracture healing as demonstrated by micro-CT and histological analyses. Collectively, these data suggest that the macromolecular prodrug-based micelle formulation of SIM may have great potential for clinical management of impaired fracture healing.

Benefits and risks of low-dose glucocorticoid treatment in the patient with rheumatoid arthritis

Glucocorticosteroids (GCs) have been employed extensively for the treatment of rheumatoid arthritis (RA) and other autoimmune and systemic inflammatory disorders. Their use is supported by extensive literature and their utility is reflected in their incorporation into current treatment guidelines for RA and other conditions. Nevertheless, there is still some concern regarding the long-term use of GCs because of their potential for clinically important adverse events, particularly with an extended duration of treatment and the use of high doses. This article systematically reviews the efficacy for radiological and clinical outcomes for low-dose GCs (defined as ≤10 mg/day prednisone equivalent) in the treatment of RA. Results reviewed indicated that low-dose GCs, usually administered in combination with synthetic DMARDs, most often MTX, significantly improve structural outcomes and decrease symptom severity in patients with RA. Safety data indicate that GC-associated adverse events are dose related, but still occur in patients receiving low doses of these agents. Concerns about side effects associated with GCs have prompted the development of new strategies aimed at improving safety without compromising efficacy. These include altering the structure of existing GCs and the development of delayed-release GC formulations so that drug delivery is timed to match greatest symptom severity. Optimal use of low-dose GCs has the potential to improve long-term outcomes for patients with RA.

Nanomedicines for inflammatory arthritis: head-to-head comparison of glucocorticoid-containing polymers, micelles, and liposomes

As an emerging research direction, nanomedicine has been increasingly utilized to treat inflammatory diseases. In this head-to-head comparison study, four established nanomedicine formulations of dexamethasone, including liposomes (L-Dex), core-cross-linked micelles (M-Dex), slow releasing polymeric prodrugs (P-Dex-slow), and fast releasing polymeric prodrugs (P-Dex-fast), were evaluated in an adjuvant-induced arthritis rat model with an equivalent dose treatment design. It was found that after a single i.v. injection, the formulations with the slower drug release kinetics (i.e., M-Dex and P-Dex-slow) maintained longer duration of therapeutic activity than those with relatively faster drug release kinetics, resulting in better joint protection. This finding will be instructional in the future development and optimization of nanomedicines for the clinical management of rheumatoid arthritis. The outcome of this study also illustrates the value of such head-to-head comparison studies in translational nanomedicine research.

Targeting nuclear receptors with marine natural products

Nuclear receptors (NRs) are important pharmaceutical targets because they are key regulators of many metabolic and inflammatory diseases, including diabetes, dyslipidemia, cirrhosis, and fibrosis. As ligands play a pivotal role in modulating nuclear receptor activity, the discovery of novel ligands for nuclear receptors represents an interesting and promising therapeutic approach. The search for novel NR agonists and antagonists with enhanced selectivities prompted the exploration of the extraordinary chemical diversity associated with natural products. Recent studies involving nuclear receptors have disclosed a number of natural products as nuclear receptor ligands, serving to re-emphasize the translational possibilities of natural products in drug discovery. In this review, the natural ligands of nuclear receptors will be described with an emphasis on their mechanisms of action and their therapeutic potentials, as well as on strategies to determine potential marine natural products as nuclear receptor modulators.

Statins, bone metabolism and treatment of bone catabolic diseases

The discovery that statins had bone anabolic properties initiated many investigations into their use for treatment of bone catabolic diseases, such as osteoporosis. This paper reviews the molecular basis of statin's role in bone metabolism, and animal and human studies on the impact of systemic statins on osteoporosis-induced bone fracture incidence and healing, and on bone density. Limitations of systemic statins are described along with alternative dosing strategies, including local applications and bone-targeting systemic preparations. The principal findings of this review are: (1) traditional oral dosing with statins results in minimal efficacy in the treatment of osteoporosis; (2) local applications of statins show promise in the treatment of accessible bony defects, such as periodontitis; and (3) systemically administered statins which can target bone or inflammation near bone may be the safest and most effective strategy in the treatment of osseous deficiencies.

Macromolecular prodrug of dexamethasone prevents particle-induced peri-implant osteolysis with reduced systemic side effects

Aseptic implant loosening related to implant wear particle-induced inflammation is the most common cause of failure after joint replacement. Modulation of the inflammatory reaction to the wear products represents a rational approach for preventing aseptic implant failure. Long-term treatment using anti-inflammatory agents, however, can be associated with significant systemic side effects due to the drugs' lack of tissue specificity. To address this issue, N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-dexamethasone conjugate (P-Dex) was developed and evaluated for prevention of wear particle-induced osteolysis and the loss of fixation in a murine prosthesis failure model. Daily administration of free dexamethasone (Dex) was able to prevent wear particle-induced osteolysis, as assessed by micro-CT and histological analysis. Remarkably, monthly P-Dex administration (dose equivalent to free Dex treatment) was equally effective as free dexamethasone, but was not associated with systemic bone loss (a major adverse side effect of glucocorticoids). The reduced systemic toxicity of P-Dex is related to preferential targeting of the sites of wear particle-induced inflammation and its subcellular sequestration and retention by local inflammatory cell populations, resulting in sustained therapeutic action. These results demonstrate the feasibility of utilizing a macromolecular prodrug with reduced systemic toxicity to prevent wear particle-induced osteolysis.

A dexamethasone prodrug reduces the renal macrophage response and provides enhanced resolution of established murine lupus nephritis

We evaluated the ability of a macromolecular prodrug of dexamethasone (P-Dex) to treat lupus nephritis in (NZB × NZW)F1 mice. We also explored the mechanism underlying the anti-inflammatory effects of this prodrug. P-Dex eliminated albuminuria in most (NZB × NZW)F1 mice. Furthermore, P-Dex reduced the incidence of severe nephritis and extended lifespan in these mice. P-Dex treatment also prevented the development of lupus-associated hypertension and vasculitis. Although P-Dex did not reduce serum levels of anti-dsDNA antibodies or glomerular immune complexes, P-Dex reduced macrophage recruitment to the kidney and attenuated tubulointerstitial injury. In contrast to what was observed with free dexamethasone, P-Dex did not induce any deterioration of bone quality. However, P-Dex did lead to reduced peripheral white blood cell counts and adrenal gland atrophy. These results suggest that P-Dex is more effective and less toxic than free dexamethasone for the treatment of lupus nephritis in (NZB × NZW)F1 mice. Furthermore, the data suggest that P-Dex may treat nephritis by attenuating the renal inflammatory response to immune complexes, leading to decreased immune cell infiltration and diminished renal inflammation and injury.