Targeting Multiple End Organs in Lupus and Other Systemic Rheumatic Diseases by Inhibiting Bruton's Tyrosine Kinase

Protective effects of BTK inhibition by acalabrutinib on cisplatin-induced renal and testicular injury in mice: Modulation of mTOR/AMPK, NLRP3/GSDMD-N, and apoptotic pathways

BACKGROUND

Cisplatin-induced nephrotoxicity and testicular injury pose significant challenges during chemotherapy.

AIM

The current study evaluates the efficacy of acalabrutinib (ACB), a Bruton's tyrosine kinase inhibitor, in mitigating cisplatin-induced damage in renal and testicular tissues in mice.

METHODS

Testicular and renal toxicity was induced by a single I.P. injection of cisplatin (25 mg/kg). Mice were randomized into four groups: Normal (treated with vehicle), Cis (cisplatin + vehicle), Cis + ACB (6 mg/kg), and Cis + ACB (12 mg/kg). ACB was administered orally for three consecutive days, starting at Day 0 (1  h before single I.P. injection of cisplatin) and continued for Day 1 and Day 2.

RESULTS

ACB treatment (6 mg/kg and 12 mg/kg) significantly improved renal function by reducing serum creatinine, BUN, and KIM-1 levels, while also attenuating inflammation and apoptosis, as evidenced by decreased NLRP3, CD68, and caspase-3 expression. Additionally, it mitigated molecular damage by downregulating mTOR, AMPK, and GSDMD-N. In testicular tissues, ACB preserved structure, restored spermatogenesis, and improved sperm viability and testosterone levels. The protective effects were associated with reduced inflammation, apoptosis, and pyroptosis, indicated by lower levels of cathepsin L, NLRP3, and GSDMD-N.

CONCLUSIONS

These findings suggest that ACB offers a promising therapeutic approach to reduce the adverse effects of cisplatin, potentially enhancing the overall efficacy and safety of chemotherapy regimens.

Infiltrating macrophages and interferon gamma rather than renal genotype dictate heightened crescentic glomerulonephritis

BACKGROUND

Both intrinsic renal cells and immune cells contribute to driving renal inflammation and damage. However, the respective roles of intrinsic renal cells and immune cells in crescentic glomerulonephritis, and the key molecular factors driving pathogenesis are still unclear.

METHODS

The roles of intrinsic renal cells and renal infiltrating immune cells in crescent formation were explored using renal transplantation after experimental anti-GBM disease induction in 129x1/svJ and C57BL/6J mice. Both strains share MHC, but vary in anti-GBM nephritis susceptibility. The role of macrophage and IFN-γ in crescent formation was investigated using adoptive transfer of macrophages with altered IFN-γ expression. The gene expression profile difference between 129x1/svJ and C57BL/6J macrophages was compared using Affymetrix arrays and Gene Ontology (GO) enrichment analysis.

RESULTS

B6 recipient mice transplanted with 129x1/svJ kidneys were resistant to anti-GBM challenge, as evidenced by stable renal function and less severe renal pathology. Conversely, 129x1/svJ recipient mice receiving B6 kidneys developed severe renal damage with crescent formation, comparable to the disease in parental 129x1/svJ mice. 129x1/svJ macrophages exhibited heightened IFN-γ and IFN-γ related gene expression compared to B6 macrophages. Adoptive transfer of 129x1/svJ macrophages with subdued IFN-γ expression reduced anti-GBM nephritis, while B6 macrophages with up-regulated IFN- γ expression worsened renal damage.

CONCLUSION

Using renal transplantation between 129x1/svJ and C57BL/6J mice and anti-GBM disease induction, we found infiltrating immune cells, not intrinsic renal cells, to play the dominant role in initialing and driving glomerular crescent formation. In particular, macrophage IFN-γ expression was critical for crescent formation.

Fibroblast growth factor 21 mitigates lupus nephritis progression via the FGF21/Irgm 1/NLRP3 inflammasome pathway

As an endocrine cytokine, fibroblast growth factor 21 (FGF21) exhibits anti-inflammatory properties. With the development of lupus nephritis (LN), which is tightly related to pathogenic factors, including inflammation and immune cell dysregulation, we explored the impact of Fibroblast Growth Factor 21 (FGF21) as well as its underlying mechanism. We induced an in vivo LN model using pristane in both wild-type C57BL/6 and FGF21 knockout (FGF21-/-) mice. LN serum obtained from 32-week-old wild-type LN mice was used to stimulate RAW264.7 and human renal tubular epithelial (HK-2) cells to mimic an in vitro LN model. Moreover, our findings revealed that FGF21-/- mice showed more severe kidney injury compared to wild-type mice, as evidenced by increased levels of renal function markers, inflammatory factors, and fibrosis markers. Notably, exogenous administration of FGF21 to wild-type LN mice markedly mitigated these adverse effects. Additionally, we used tandem mass tag (TMT)-based quantitative proteomics to detect differentially expressed proteins following FGF21 treatment. Results indicated that 121 differentially expressed proteins influenced by FGF21 were involved in biological processes such as immune response and complement activation. Significantly upregulated protein Irgm 1, coupled with modulated inflammatory response, appeared to contribute to the beneficial effects of FGF21. Furthermore, Western blot analysis demonstrated that FGF21 upregulated Irgm 1 while inhibiting nucleotide-binding oligomerization domain-like receptors family pyrin domain including 3 (NLRP3) inflammasome expression. Silencing Irgm 1, in turn, reversed FGF21's inhibitory effect on NLRP3 inflammasome. In summary, FGF21 can potentially alleviate pristane-induced lupus nephritis in mice, possibly through the FGF21/Irgm 1/NLRP3 inflammasome pathway.

Faslpr gene dosage tunes the extent of lymphoproliferation and T cell differentiation in lupus

Sle1 and Faslpr are two lupus susceptibility loci that lead to manifestations of systemic lupus erythematosus. To evaluate the dosage effects of Faslpr in determining cellular and serological phenotypes associated with lupus, we developed a new C57BL/6 (B6) congenic lupus strain, B6.Sle1/Sle1.Faslpr/+ (Sle1homo.lprhet) and compared it with B6.Faslpr/lpr (lprhomo), B6.Sle1/Sle1 (Sle1homo), and B6.Sle1/Sle1.Faslpr/lpr (Sle1homo.lprhomo) strains. Whereas Sle1homo.lprhomo mice exhibited profound lymphoproliferation and early mortality, Sle1homo.lprhet mice had a lifespan comparable to B6 mice, with no evidence of splenomegaly or lymphadenopathy. Compared to B6 monogenic lupus strains, Sle1homo.lprhet mice exhibited significantly elevated serum ANA antibodies and increased proteinuria. Additionally, Sle1homo.lprhet T cells had an increased propensity to differentiate into Th1 cells. Gene dose effects of Faslpr were noted in upregulating serum IL-1⍺, IL-2, and IL-27. Taken together, Sle1homo.lprhet strain is a new C57BL/6-based model of lupus, ideal for genetic studies, autoantibody repertoire investigation, and for exploring Th1 effector cell skewing without early-age lymphoproliferative autoimmunity.

NETosis: an emerging therapeutic target in renal diseases

Introduction

Neutrophil extracellular traps (NETs) are web-like structures composed of nuclear and granular components. The primary role of NETS is to prevent the dissemination of microbes and facilitate their elimination. However, this process is accompanied by collateral proinflammatory adverse effects when the NET release becomes uncontrollable, or clearance is impaired. Although NET-induced organ damage is conducted primarily and indirectly via immune complexes and the subsequent release of cytokines, their direct effects on cells are also remarkable. NETosis plays a critical pathogenic role in several renal disorders, such as the early phase of acute tubular necrosis, anti-neutrophil cytoplasmic antibody-mediated renal vasculitis, lupus nephritis, thrombotic microangiopathies, anti-glomerular basement membrane disease, and diabetic nephropathy. Their substantial contribution in the course of these disorders makes them a desirable target in the therapeutic armamentarium. This article gives an in-depth review of the heterogeneous pathogenesis and physiological regulations of NETosis and its pivotal role in renal diseases. Based on the pathogenesis, the article also outlines the current therapeutic options and possible molecular targets in the treatment of NET-related renal disorders.

Methods

We carried out thorough literature research published in PubMed and Google Scholar, including a comprehensive review and analysis of the classification, pathomechanisms, and a broad spectrum of NET-related kidney disorders.

Conclusions

NETosis plays a pivotal role in certain renal diseases. It initiates and maintains inflammatory and autoimmune disorders, thus making it a desirable target for improving patient and renal outcomes. Better understanding and clinical translation of the pathogenesis are crucial aspects to treatment, for improving patient, and renal outcomes.

Novel Therapeutic Strategies in the Treatment of Systemic Sclerosis

Systemic sclerosis is a connective tissue disease of unknown origin and with an unpredictable course, with both cutaneous and internal organ manifestations. Despite the enormous progress in rheumatology and clinical immunology, the background of this disease is largely unknown, and no specific therapy exists. The therapeutic approach aims to treat and preserve the function of internal organs, and this approach is commonly referred to as organ-based treatment. However, in modern times, data from other branches of medicine may offer insight into how to treat disease-related complications, making it possible to find new drugs to treat this disease. In this review, we present therapeutic options aiming to stop the progression of fibrotic processes, restore the aberrant immune response, stop improper signalling from proinflammatory cytokines, and halt the production of disease-related autoantibodies.