The landscape of transcriptomic and proteomic studies in sarcoidosis

Therapeutic doses of efzofitimod demonstrate efficacy in pulmonary sarcoidosis

Background

In a phase 1b/2a clinical trial of efzofitimod in patients with corticosteroid-requiring pulmonary sarcoidosis, treatment resulted in dose-dependent improvement in key end-points. We undertook a post hoc analysis pooling dose arms that achieved therapeutic concentrations of efzofitimod (Therapeutic group) versus those that did not (Subtherapeutic group).

Methods

Peripheral blood mononuclear cells incubated with tuberculin-coated beads were exposed to varying concentrations of efzofitimod in an in vitro assay to determine concentrations that inhibited granuloma formation. In the post hoc analysis, we compared time-to-first-relapse and changes in pulmonary function after a protocolised corticosteroid taper in the Therapeutic and Subtherapeutic groups.

Results

Efzofitimod at ≥300 nM (19 µg·mL-1) inhibited granuloma formation in vitro. Based on mean efzofitimod serum concentrations achieved in the phase 1b/2a study, the 3 and 5 mg·kg-1 dose arms were pooled as the Therapeutic group, while the 1 mg·kg-1 arm was pooled with the placebo arm as the Subtherapeutic group. Relapse rates were 54.4% and 7.7% in the Subtherapeutic group and Therapeutic group, respectively. Median time-to-first-relapse in the Subtherapeutic group was 126 days, whereas in the Therapeutic group, only one of 17 patients relapsed by the end of the 24-week study (p=0.017). Slopes analysis showed that forced vital capacity increased in the Therapeutic group, but decreased in the Subtherapeutic group, over the course of the trial (p=0.035).

Conclusion

Treatment with efzofitimod at therapeutic doses, as compared with a subtherapeutic dose or placebo, was associated with a lower rate of relapse as corticosteroids were tapered.

Application of laboratory models for sarcoidosis research

This manuscript will review the implications and applications of sarcoidosis models towards advancing our understanding of sarcoidosis disease mechanisms, identification of biomarkers, and preclinical testing of novel therapies. Emerging disease models and innovative research tools will also be considered.

Big data in sarcoidosis

PURPOSE OF REVIEW

This review provides an overview of recent advancements in sarcoidosis research, focusing on collaborative networks, phenotype characterization, and molecular studies. It highlights the importance of collaborative efforts, phenotype characterization, and the integration of multilevel molecular data for advancing sarcoidosis research and paving the way toward personalized medicine.

RECENT FINDINGS

Sarcoidosis exhibits heterogeneous clinical manifestations influenced by various factors. Efforts to define sarcoidosis endophenotypes show promise, while technological advancements enable extensive molecular data generation. Collaborative networks and biobanks facilitate large-scale studies, enhancing biomarker discovery and therapeutic protocols.

SUMMARY

Sarcoidosis presents a complex challenge due to its unknown cause and heterogeneous clinical manifestations. Collaborative networks, comprehensive phenotype delineation, and the utilization of cutting-edge technologies are essential for advancing our understanding of sarcoidosis biology and developing personalized medicine approaches. Leveraging large-scale epidemiological resources and biobanks and integrating multilevel molecular data offer promising avenues for unraveling the disease's heterogeneity and improving patient outcomes.

The Renin-Angiotensin-Aldosterone System Regulates Sarcoidosis Granulomatous Inflammation

Rationale: Sarcoidosis is a granulomatous disorder of unclear cause notable for abnormal elevation of blood and tissue ACE1 (angiotensin converting enzyme 1) levels and activity. ACE1 regulates the renin-angiotensin-aldosterone system (RAAS), the terminal product of which is aldosterone, which selectively engages mineralocorticoid receptors to promote inflammation. Objectives: We sought to determine whether the RAAS promotes sarcoidosis granuloma formation and related inflammatory responses. Methods: Using an established ex vivo model, we first determined whether aldosterone was produced by sarcoidosis granulomas and verified the presence of CYP11B2, the enzyme required for its production. We then evaluated the effects of selective inhibitors of ACE1 (captopril), angiotensin type 1 receptor (losartan), and mineralocorticoid receptors (spironolactone, eplerenone) on granuloma formation, reflected by computer image analysis-generated granuloma area, and selected cytokines incriminated in sarcoidosis pathogenesis. Measurements and Main Results: Aldosterone was spontaneously produced by sarcoidosis peripheral blood mononuclear cells, and both intra- and extracellular levels steadily increased during granuloma formation. In parallel, peripheral blood mononuclear cells were shown to express more CYP11B2 during granuloma formation. Significant inhibition of sarcoidosis granulomas and related cytokines (TNFα, IL-1β, IFNγ, IL-10) was observed in response to pretreatments with captopril, losartan, spironolactone, or eplerenone, comparable to that of prednisone. Conclusions: The RAAS is intact in sarcoidosis granulomas and contributes significantly to early granuloma formation and to related inflammatory mediator responses, with important implications for clinical management.

Investigating cryopreserved PBMC functionality in an antigen-induced model of sarcoidosis granuloma formation

Sarcoidosis, a systemic inflammatory disease, poses challenges in understanding its etiology and variable clinical courses. Despite ongoing uncertainty about causative agents and genetic predisposition, granuloma formation remains its hallmark feature. To address this, we developed a validated in vitro human granuloma model using patient-derived peripheral blood mononuclear cells (PBMCs), offering a dynamic platform for studying early granuloma formation and sarcoidosis pathogenesis. However, a current limitation of this model is its dependence on freshly isolated PBMCs obtained from whole blood. While cryopreservation is a common method for long-term sample preservation, the biological effects of freezing and thawing PBMCs on granuloma formation remain unclear. This study aimed to assess the viability and functionality of cryopreserved sarcoidosis PBMCs within the granuloma model, revealing similar granulomatous responses to fresh cells and highlighting the potential of cryopreserved PBMCs as a valuable tool for studying sarcoidosis and related diseases.

Bioinformatic meta-analysis reveals novel differentially expressed genes and pathways in sarcoidosis

Introduction

Sarcoidosis is a multi-system inflammatory disease of unknown origin with heterogeneous clinical manifestations varying from a single organ non-caseating granuloma site to chronic systemic inflammation and fibrosis. Gene expression studies have suggested several genes and pathways implicated in the pathogenesis of sarcoidosis, however, due to differences in study design and variable statistical approaches, results were frequently not reproducible or concordant. Therefore, meta-analysis of sarcoidosis gene-expression datasets is of great importance to robustly establish differentially expressed genes and signalling pathways.

Methods

We performed meta-analysis on 22 published gene-expression studies on sarcoidosis. Datasets were analysed systematically using same statistical cut-offs. Differentially expressed genes were identified by pooling of p-values using Edgington's method and analysed for pathways using Ingenuity Pathway Analysis software.

Results

A consistent and significant signature of novel and well-known genes was identified, those collectively implicated both type I and type II interferon mediated signalling pathways in sarcoidosis. In silico functional analysis showed consistent downregulation of eukaryotic initiation factor 2 signalling, whereas cytokines like interferons and transcription factor STAT1 were upregulated. Furthermore, we analysed affected tissues to detect differentially expressed genes likely to be involved in granuloma biology. This revealed that matrix metallopeptidase 12 was exclusively upregulated in affected tissues, suggesting a crucial role in disease pathogenesis.

Discussion

Our analysis provides a concise gene signature in sarcoidosis and expands our knowledge about the pathogenesis. Our results are of importance to improve current diagnostic approaches and monitoring strategies as well as in the development of targeted therapeutics.

Integrative single-cell analysis of cardiac and pulmonary sarcoidosis using publicly available cardiac and bronchoalveolar lavage fluid sequencing datasets

Introduction

Cardiac presentation of autoimmune sarcoidosis, known as cardiac sarcoidosis (CS), is a poorly understood disease with high mortality and low diagnosis rate. While CS is an immunological syndrome, little is known about how cardiac parenchymal and stromal cells mediate its pathogenesis. Moreover, while most current sarcoidosis research is based on research in pulmonary sarcoidosis (PS), it remains unclear how much both presentations of sarcoidosis overlap. To tackle these concerns, we leveraged publicly available sarcoidosis transcriptomic datasets.

Methods

Two publicly available bronchoalveolar lavage single-cell RNA sequencing datasets were integrated to analyze PS relative to control. Additionally, two publicly available cardiac single-nucleus RNA sequencing datasets were integrated to analyze CS relative to control. Following integration, we ran cell-cell communication, transcription factor, and differential expression analyses on parenchymal, stromal, and immune subsets identified in our analysis.

Results

Our analysis revealed that there was an expansion of stromal and immune cells in PS and CS. We also observed upregulation of Th17.1 and attenuated activation transcriptional profiles in the immune cells of CS and PS relative to control. Additionally, we found upregulation of pro-inflammatory and pro-fibrotic transcriptional profiles in the cardiac stromal cells of CS relative to control. We also found that cardiomyocytes exhibited upregulated cardiac stress and proliferation transcriptional profiles in CS relative to control.

Conclusions

Our integrative transcriptomic analysis shows that despite tissue-specific differences, there are shared transcriptional trends between CS and PS. It also shows that stromal and parenchymal populations exhibit transcriptional trends that could explain their pathogenic role in CS.

From Karl Wurm and Guy Scadding's staging to 18F-FDG PET/CT scan phenotyping and far beyond: perspective in the evading history of phenotyping in sarcoidosis

Sarcoidosis is an inflammatory granulomatous disease of unknown etiology involving any organ or tissue along with any combination of active sites, even the most silent ones clinically. The unpredictable nature of the sites involved in sarcoidosis dictates the highly variable natural history of the disease and the necessity to cluster cases at diagnosis based on clinical and/or imaging common characteristics in an attempt to classify patients based on their more homogeneous phenotypes, possibly with similar clinical behavior, prognosis, outcome, and therefore with therapeutic requirements. In the course of the disease's history, this attempt relates to the availability of a means of detection of the sites involved, from the Karl Wurm and Guy Scadding's chest x-ray staging through the ACCESS, the WASOG Sarcoidosis Organ Assessment Instruments, and the GenPhenReSa study to the 18F-FDG PET/CT scan phenotyping and far beyond to new technologies and/or the current "omics." The hybrid molecular imaging of the 18F-FDG PET/CT scan, by unveiling the glucose metabolism of inflammatory cells, can identify high sensitivity inflammatory active granulomas, the hallmark of sarcoidosis-even in clinically and physiologically silent sites-and, as recently shown, is successful in identifying an unexpected ordered stratification into four phenotypes: (I) hilar-mediastinal nodal, (II) lungs and hilar-mediastinal nodal, (III) an extended nodal supraclavicular, thoracic, abdominal, inguinal, and (IV) all the above in addition to systemic organs and tissues, which is therefore the ideal phenotyping instrument. During the "omics era," studies could provide significant, distinct, and exclusive insights into sarcoidosis phenotypes linking clinical, laboratory, imaging, and histologic characteristics with molecular signatures. In this context, the personalization of treatment for sarcoidosis patients might have reached its goal.

Leveraging in vitro and pharmacokinetic models to support bench to bedside investigation of XTMAB-16 as a novel pulmonary sarcoidosis treatment

Background: Sarcoidosis is a chronic, multisystem inflammatory disorder characterized by non-caseating epithelioid granulomas; infiltration of mononuclear cells; and destruction of microarchitecture in the skin, eye, heart, and central nervous system, and the lung in >90% of cases. XTMAB-16 is a chimeric anti-tumor necrosis factor alpha (TNFα) antibody, distinct from other anti-TNF antibodies based on its molecular structure. The efficacy of XTMAB-16 has not been clinically demonstrated, and it is still undergoing clinical development as a potential treatment for sarcoidosis. The current study demonstrates the activity of XTMAB-16 in a well-established in vitro sarcoidosis granuloma model, although XTMAB-16 is not yet approved by the United States Food and Drug Administration (FDA) for treatment of sarcoidosis, or any other disease. Objective: To provide data to guide safe and efficacious dose selection for the ongoing clinical development of XTMAB-16 as a potential treatment for sarcoidosis. Methods: First, XTMAB-16 activity was evaluated in an established in vitro model of granuloma formation using peripheral blood mononuclear cells from patients with active pulmonary sarcoidosis to determine a potentially efficacious dose range. Second, data obtained from the first-in-human study of XTMAB-16 (NCT04971395) were used to develop a population pharmacokinetic (PPK) model to characterize the pharmacokinetics (PK) of XTMAB-16. Model simulations were performed to evaluate the sources of PK variability and to predict interstitial lung exposure based on concentrations in the in vitro granuloma model. Results: XTMAB-16 dose levels of 2 and 4 mg/kg, once every 2 weeks (Q2W) or once every 4 weeks (Q4W) for up to 12 weeks, were supported by data from the non-clinical, in vitro secondary pharmacology; the Phase 1 clinical study; and the PPK model developed to guide dose level and frequency assumptions. XTMAB-16 inhibited granuloma formation and suppressed interleukin-1β (IL-1β) secretion in the in vitro granuloma model with a half maximal inhibitory concentration (IC₅₀) of 5.2 and 3.5 μg/mL, respectively. Interstitial lung concentrations on average, following 2 or 4 mg/kg administered Q2W or Q4W, are anticipated to exceed the in vitro IC₅₀ concentrations. Conclusion: The data presented in this report provide a rationale for dose selection and support the continued clinical development of XTMAB-16 for patients with pulmonary sarcoidosis.

Immune mechanisms in fibrotic pulmonary sarcoidosis

Sarcoidosis is an immune-mediated disorder. Its immunopathology has been steadily mapped out over the past few decades. Despite this, the underpinning mechanisms for progressive fibrotic sarcoidosis is an almost uncharted area. Consequently, there has been little change in the clinical management of fibrotic sarcoidosis over the decades and an unfocused search for new therapeutics. In this review, we provide a comprehensive examination of the relevant immune findings in fibrotic and/or progressive pulmonary sarcoidosis and propose a unifying mechanism for the pathobiology of fibrosis in sarcoidosis.