Comparative effects of human-equivalent low, moderate, and high dose oral prednisone intake on autoimmunity and glucocorticoid-related toxicity in a murine model of environmental-triggered lupus

Global scenario of silica-associated diseases: A review on emerging pathophysiology of silicosis and potential therapeutic regimes

Silicosis is an occupational fibrotic lung disease caused by exposure to respirable crystalline silica dust particles produced during industrial activities. Other crystalline silica-induced pulmonary disorders include a predisposition to mycobacterial infections, obstructive airway diseases, idiopathic pulmonary fibrosis, and lung cancer. This review paper discusses the burden of silicosis and associated co-morbidities in developed as well as developing countries globally using the published data of various government agencies, related organizations, and epidemiological findings. Moreover, it sheds light on diverse mechanisms of silicosis, outlining molecular events and peculiar alterations in lung parenchyma leading to this occupational lung disease. Evaluation of pathophysiological mechanisms could aid in the identification of novel target molecules and treatments; to date, there is no curative treatment for silicosis. In recent periods, a lot of attention has been focused on the development and fabrication of suitable nanocarriers for improved and sustained drug delivery in the pulmonary system. Nanoparticle-based therapeutic modality has been evaluated in in-vitro and ex-vivo silicosis models for prolongation of drug activity and improved therapeutic outcomes. The preclinical findings open the doors to clinical trials for operational and regenerative nanoformulations, which eventually create a positive change in medical practice. The following review summarizes various therapeutic approaches available and in the pipe line for silicosis and also stresses the preventive practices for effectively combating this occupational hazard.

Nanoparticle platform preferentially targeting liver sinusoidal endothelial cells induces tolerance in CD4+ T cell-mediated disease models

Introduction

Treating autoimmune diseases without nonspecific immunosuppression remains challenging. To prevent or treat these conditions through targeted immunotherapy, we developed a clinical-stage nanoparticle platform that leverages the tolerogenic capacity of liver sinusoidal endothelial cells (LSECs) to restore antigen-specific immune tolerance.

Methods

In vivo efficacy was evaluated in various CD4+ T cell-mediated disease models, including preventive and therapeutic models of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (EAE), ovalbumin-sensitized delayed-type hypersensitivity (DTH), and the spontaneous type 1 diabetes model. Nanoparticle-induced antigen-specific immune responses were also analyzed through adoptive transfers of 2D2 transgenic T cells into wild-type mice, followed by nanoparticle administration.

Results

The peptide-conjugated nanoparticles displayed a uniform size distribution (25-30 nm). Their coupling efficiency for peptides with unfavorable physicochemical properties was significantly enhanced by a proprietary linker technology. Preferential LSEC targeting of nanoparticles coupled with fluorescently labeled peptides was confirmed via intravital microscopy and flow cytometry. Intravenous nanoparticle administration significantly reduced disease severity and demyelination in EAE, independent of prednisone at maintenance doses, and suppressed target tissue inflammation in the DTH model. Furthermore, prophylactic administration of a mixture of nanoparticles coupled with five autoantigenic peptides significantly lowered the hyperglycemia incidence of the non-obese diabetic mice. Mechanistically, the tolerizing effects were associated with the induction of antigen-specific regulatory T cells and T cell anergy, which counteract proinflammatory T cells in the target tissue.

Conclusion

Our findings demonstrate that peptide-loaded nanoparticles preferentially deliver disease-relevant peptides to LSECs, thereby inducing antigen-specific immune tolerance. This versatile clinical-stage nanoparticle platform holds promise for clinical application across multiple autoimmune diseases.

Decreasing miR-433-3p Activity in the Osteoblast Lineage Blunts Glucocorticoid-mediated Bone Loss

Glucocorticoid excess causes bone loss due to decreased bone formation and increased bone resorption; miR-433-3p is a microRNA (miRNA) that negatively regulates bone formation in male mice by targeting Runx2 as well as RNAs involved in Wnt, protein kinase A, and endogenous glucocorticoid signaling. To examine the impact of miR-433-3p on glucocorticoid-mediated bone loss, transgenic mice expressing a miR-433-3p tough decoy inhibitor in the osteoblast lineage were administered prednisolone via slow-release pellets. Bone loss was greater in control mice treated with prednisolone compared with miR-433-3p tough decoy mice due to higher osteoclast activity in the controls. In whole femurs, Rankl was significantly higher in prednisolone-treated controls compared with miR-433-3p tough decoy mice. Surprisingly, negative regulators of Wnt signaling Sost and Dkk1 were higher in miR-433-3p tough decoy mice and were unaffected by prednisolone. Luciferase- 3'-untranslated region reporter assays demonstrated that Sost is a novel miR-433-3p target, whereas Dkk1 is a previously validated miR-433-3p target. miR-433-3p levels are lower in matrix-synthesizing osteoblasts than in more osteocytic cells; thus the impact of miR-433-3p on the osteoblast lineage may be dependent on cell context: it is a negative regulator in matrix-depositing osteoblasts by targeting RNAs important for differentiation and function but a positive regulator in osteocytes, due to its ability to target prominently expressed negative regulators of Wnt signaling, Sost and Dkk1. The mechanisms by which miR-433-3p indirectly regulates glucocorticoid-mediated osteoclastogenesis remain unknown. However, we speculate that this regulation may be mediated by miR-433-3p activity in osteocytes, which play an important role in controlling osteoclastogenesis.

Prednisolone pharmacokinetics in dogs with protein-losing enteropathy

BACKGROUND

It is unknown if glucocorticoid malabsorption contributes to the approximate 50% treatment failure rate in dogs with protein-losing enteropathy (PLE).

OBJECTIVE

To compare pharmacokinetics (PK) of orally administered prednisolone in dogs with PLE vs healthy controls.

ANIMALS

Fourteen dogs with well-characterized PLE and 7 control dogs.

METHODS

Prospective case-controlled study. Dogs were treated with 1 mg/kg prednisolone PO once daily for approximately 3 weeks. Venous blood samples were collected at set timepoints before and after prednisolone administration on the first (T1) and final (T2) study days. Total and non-protein bound serum prednisolone concentrations were determined using liquid chromatography tandem-mass spectrometry, and pharmacokinetics variables were derived from the drug concentration data. Pharmacokinetics variables were compared between PLE and control dogs and between PLE short-term responders and non-responders.

RESULTS

The PLE dogs had a shorter half-life of the terminal slope than control dogs (harmonic mean of 1.3 vs 1.8 hours; P = .05) whereas the percentage of serum prednisolone that was non-protein bound was higher in PLE dogs than in control dogs (median of 15.7% vs 6.7%; P = .02) at T1. Total prednisolone drug exposures and maximum total serum drug concentrations did not differ between PLE and control dogs at T1 or T2, nor did they differ between short-term responders and non-responders within the PLE population (P > .05 for all comparisons).

CONCLUSIONS AND CLINICAL IMPORTANCE

Overall drug exposures are similar between PLE dogs and healthy controls. Glucocorticoid malabsorption is unlikely to be a common cause of treatment failure in dogs with PLE.

Crystalline silica-induced pulmonary inflammation and autoimmunity in mature adult NZBW/f1 mice: age-related sensitivity and impact of omega-3 fatty acid intervention

OBJECTIVE

Occupational exposure to respirable crystalline silica (cSiO2) has been linked to lupus development. Previous studies in young lupus-prone mice revealed that intranasal cSiO2 exposure triggered autoimmunity, preventable with docosahexaenoic acid (DHA). This study explores cSiO2 and DHA effects in mature lupus-prone adult mice, more representative of cSiO2-exposed worker age.

METHODS

Female NZBWF1 mice (14-week old) were fed control (CON) or DHA-supplemented diets. After two weeks, mice were intranasally instilled saline (VEH) or 1 mg cSiO2 weekly for four weeks. Cohorts were then analyzed 1- and 5-weeks postinstillation for lung inflammation, cell counts, chemokines, histopathology, B- and T-cell infiltration, autoantibodies, and gene signatures, with results correlated to autoimmune glomerulonephritis onset.

RESULTS

VEH/CON mice showed no pathology. cSiO2/CON mice displayed significant ectopic lymphoid tissue formation in lungs at 1 week, increasing by 5 weeks. cSiO2/CON lungs exhibited elevated cellularity, chemokines, CD3+ T-cells, CD45R + B-cells, IgG + plasma cells, gene expression, IgG autoantibodies, and glomerular hypertrophy. DHA supplementation mitigated all these effects.

DISCUSSION

The mature adult NZBWF1 mouse used here represents a life-stage coincident with immunological tolerance breach and one that more appropriately represents the age (20-30 yr) of cSiO2-exposed workers. cSiO2-induced robust pulmonary inflammation, autoantibody responses, and glomerulonephritis in mature adult mice, surpassing effects observed previously in young adults. DHA at a human-equivalent dosage effectively countered cSiO2-induced inflammation/autoimmunity in mature mice, mirroring protective effects in young mice.

CONCLUSION

These results highlight life-stage significance in this preclinical lupus model and underscore omega-3 fatty acids' therapeutic potential against toxicant-triggered autoimmune responses.

Tertiary lymphoid structures as local perpetuators of organ-specific immune injury: implication for lupus nephritis

In response to inflammatory stimuli in conditions such as autoimmune disorders, infections and cancers, immune cells organize in nonlymphoid tissues, which resemble secondary lymphoid organs. Such immune cell clusters are called tertiary lymphoid structures (TLS). Here, we describe the potential role of TLS in the pathogenesis of autoimmune disease, focusing on lupus nephritis, a condition that incurs major morbidity and mortality. In the kidneys of patients and animals with lupus nephritis, the presence of immune cell aggregates with similar cell composition, structure, and gene signature as lymph nodes and of lymphoid tissue-inducer and -organizer cells, along with evidence of communication between stromal and immune cells are indicative of the formation of TLS. TLS formation in kidneys affected by lupus may be instigated by local increases in lymphorganogenic chemokines such as CXCL13, and in molecules associated with leukocyte migration and vascularization. Importantly, the presence of TLS in kidneys is associated with severe tubulointerstitial inflammation, higher disease activity and chronicity indices, and poor response to treatment in patients with lupus nephritis. TLS may contribute to the pathogenesis of lupus nephritis by increasing local IFN-I production, facilitating the recruitment and supporting survival of autoreactive B cells, maintaining local production of systemic autoantibodies such as anti-dsDNA and anti-Sm/RNP autoantibodies, and initiating epitope spreading to local autoantigens. Resolution of TLS, along with improvement in lupus, by treating animals with soluble BAFF receptor, docosahexaenoic acid, complement inhibitor C4BP(β-), S1P1 receptor modulator Cenerimod, dexamethasone, and anti-CXCL13 further emphasizes a role of TLS in the pathogenesis of lupus. However, the mechanisms underlying TLS formation and their roles in the pathogenesis of lupus nephritis are not fully comprehended. Furthermore, the lack of non-invasive methods to visualize/quantify TLS in kidneys is also a major hurdle; however, recent success in visualizing TLS in lupus-prone mice by photon emission computed tomography provides hope for early detection and manipulation of TLS.

Long COVID-19 and Insulin Autoimmune Syndrome: A Case Report

PURPOSE

To describe a case report of a patient with symptoms associated with metabolic alterations 1 month after having COVID-19.

METHODS

Laboratory tests, clinical evaluations, and body composition assessments were performed by specialists.

FINDINGS

The patient presented excessive sweating, hot flashes, dizziness, blurred vision, and seizure. Laboratory tests indicated low glucose levels after convulsions (50, 42.7, and 55 mg/dL), high insulin levels (basal, 638 µIU/mL; 2-hour, >1000 µU/mL), and positivity for anti-insulin antibodies. The patient was diagnosed with insulin autoimmune syndrome. Treatment with azathioprine and nutritional recommendations improved remission.

IMPLICATIONS

SARS-CoV-2 infection or vaccination might induce insulin tolerance failure.