Efficacy and safety of mTOR inhibition in cutaneous sarcoidosis: a single-centre trial

mTOR/p70S6K signaling pathway promotes fibrillin-1 expression in AKI-to-CKD transition post CA/CPR

The possible involvement of mTOR/p70S6K signaling in mediating Fibrillin-1 expression during the transition from acute kidney injury (AKI) to chronic kidney disease (CKD) after cardiac arrest and cardiopulmonary resuscitation (CA/CPR). A CA/CPR AKI model was established using male C57BL/6 mice aged 8-12 weeks. The expression of Fibrillin-1 and activation of the mTOR/p70S6K signaling pathway in kidney tissues were assessed at different time points. Rapamycin, administered intraperitoneally, inhibited the mTOR/p70S6K signaling pathway in CA/CPR AKI mice. Tissue immunofluorescence and immunohistochemistry were used to detect the injury, fibrosis, and inflammatory cell infiltration in renal tissues. The expression level of Fibrillin-1 and components of the mTOR/p70S6K signaling pathway, while ELISA quantified levels of inflammatory factors in renal tissues. Results showed that Fibrillin-1 expression progressively increased alongside enhanced mTOR/p70S6K signaling in the renal tissues of CA/CPR AKI mice. Inhibition of mTOR/p70S6K signaling by rapamycin reduced Fibrillin-1 expression, collagen deposition, and α-SMA levels, alleviating renal injury and decreasing macrophage and T cell infiltration, as well as inflammatory factor production. Conversely, combining rapamycin with Fibrillin-1 overexpression exacerbated renal injury and increased inflammatory factor production. Activation of the mTOR/p70S6K pathway upregulates Fibrillin-1 expression, potentially facilitating the progression from AKI to CKD in CA/CPR mice.

Cutaneous sarcoidosis: clinical and pathologic features, molecular pathogenesis, and treatment

Sarcoidosis is a multisystem inflammatory disorder that most commonly affects the lungs, lymphatic system, eyes, and skin. Cutaneous involvement is present in approximately 20% to 30% patients. Prednisone and corticotropin repository are the only Food and Drug Administration-approved therapies for sarcoidosis. We review the varied cutaneous manifestations of sarcoidosis and the recommended evaluation for this disease. We also discuss histopathologic findings and outline disease pathogenesis, incorporating newer molecular data. Treatment approaches for cutaneous sarcoidosis and their associated levels of evidence are also delineated.

A review of sarcoidosis etiology, diagnosis and treatment

Sarcoidosis is an inflammatory disease characterized by the formation of granulomas in various organs, leading to inflammation and potential organ dysfunction. Symptoms often start with general signs like fatigue, fever, and weight loss, but vary depending on the affected organ. Diagnosis is challenging due to its diverse clinical presentation and lack of a definitive test, while treatment is complicated by the disease's variable course, requiring a personalized approach. This review explores the role of genetic and environmental factors in sarcoidosis etiology, examines current challenges in diagnosis and treatment, and discusses how understanding etiology informs patient management and future treatment strategies.

Shaping Rare Granulomatous Diseases in the Lab: How New Models Are Changing the Game

In vitro models serve as valuable tools for understanding the complex cellular and molecular interactions involved in granuloma formation, providing a controlled environment to explore the underlying mechanisms of their development and function. Various models have been developed to replicate granulomatous diseases, even though they may lack the sophistication needed to fully capture the variability present in clinical spectra and environmental influences. Traditional cultures of PBMCs have been widely used to generate granuloma models, enabling the study of aggregation responses to various stimuli. However, growing cells on a two-dimensional (2D) plastic surface as a monolayer can lead to altered cellular responses and the modulation of signaling pathways, which may not accurately represent in vivo conditions. In response to these limitations, the past decade has seen significant advancements in the development of three-dimensional (3D) in vitro models, which more effectively mimic in vivo conditions and provide better insights into cell-cell and cell-microenvironment interactions. Meanwhile, the use of in vivo animal models in biomedical research must adhere to the principle of the three Rs (replacement, reduction, and refinement) while ensuring that the models faithfully replicate human-specific processes. This review summarizes and compares the main models developed to investigate granulomas, focusing on their contribution to advancing our understanding of granuloma biology. We also discuss the strengths and limitations of each model, offering insights into their biological relevance and practical applications.

Exploring the anti-inflammatory effects of Radix Curcumae essential oil in pulmonary sarcoidosis via the TLR4/MyD88/NF-κB pathway

BACKGROUND

Pulmonary sarcoidosis (PS) is an immune-mediated disorder characterised by a significant association with various immune cell types including macrophages, T-helper 1 (TH1) cells, and TH17 cells. Dysregulation of immune cell differentiation leads to pronounced inflammatory responses in the pulmonary system, resulting in granuloma formation. Currently, the therapeutic approach for PS predominantly involves the use of immunosuppressive agents. However, the considerable adverse effects associated with these treatments underscore the urgent need to develop novel anti-PS pharmacological interventions.

PURPOSE

To investigate whether essential oil from Radix Curcumae (RCEO) improves pulmonary function in PS mice by inhibiting inflammation mediated by the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor kappa-B (NF-κB) (TLR4/MyD88/NF-κB) pathway.

METHODS

Bioinformatics and network pharmacology methodologies were used to predict potential therapeutic targets of RCEO in the context of PS. The primary components of RCEO were analysed using gas chromatography-mass spectrometry. A murine model of PS was established by induction with Propionibacterium acnes, and alterations in pulmonary function were evaluated using whole-body plethysmography. An enzyme-linked immunosorbent assay was used to measure changes in inflammatory mediators in the blood and bronchoalveolar lavage fluid. Additionally, flow cytometry was performed to determine the differentiation of CD4+ T cells into TH1 and TH17 subsets in the lung tissues of mice in the model group. Immunofluorescence analysis was used to quantify the differentiation of macrophages into M1 and M2 phenotypes in the lung tissues. Polymerase chain reaction (PCR) and western blotting (WB) were used to assess alterations in the mRNAs expression levels and proteins associated with the TLR4/MyD88/NF-κB signalling pathway in pulmonary tissues.

RESULTS

Bioinformatics and network pharmacology predictions suggested that the therapeutic effects of RCEO on PS are linked to the modulation of inflammation via the TLR4/MyD88/NF-κB pathway. In a murine model of PS, RCEO significantly reduced pathological alterations in lung tissue and enhanced pulmonary function. Subsequent experimental analyses revealed that RCEO inhibited the differentiation of macrophages into M1-type macrophages and reduced the differentiation of CD4+ T cells into TH1 and TH17 cells, thereby preventing granuloma formation in the mouse pulmonary tissue. Further PCR and WB analyses indicated that RCEO modulated immune cell differentiation by inhibiting inflammation mediated through the TLR4/MyD88/NF-κB signalling pathway. Immunofluorescence experiments demonstrated that RCEO conferred a protective effect against PS by attenuating inflammation in macrophages.

CONCLUSION

RCEO inhibited the differentiation of macrophages into M1-type macrophages and suppressed the differentiation of CD4+T cells into TH1 and TH17 cells by blocking the inflammatory response mediated by the TLR4/MyD88/NF-κB pathway. This further reduced the formation of granulomas in lung tissue and improved lung function in PS mice.

Sarcoidosis: molecular mechanisms and therapeutic strategies

Sarcoidosis, a multisystemic granulomatous disease with unknown etiology, is characterized by formation of noncaseating granulomas, which can affect all organs. Recent studies have made outstanding achievement in understanding the pathology, etiology, genetics, and immune dysregulation involved in granuloma formation of sarcoidosis. Antigen stimulation in genetically predisposed individuals enhances the phagocytic activity of antigen-presenting cells, including macrophages and dendritic cells. CD4 + T cells initiate dysregulated immune responses and secrete significant quantities of inflammatory cytokines, including interleukin (IL)-2 and interferon-gamma (IFN-γ), which play a crucial role in modulating the aggregation and fusion of macrophages to form granulomas. The current therapeutic strategies focus on blocking the formation and spread of granulomas to protect organ function and alleviate symptoms. The efficacy of traditional treatments, such as glucocorticoids and immunosuppressants, has been confirmed in the management of sarcoidosis. Promising therapeutic agents encompass inhibitors of cytokines, like those targeting tumor necrosis factor (TNF)-α, as well as inhibitors of signaling pathways, such as Janus kinase (JAK) inhibitors, which exhibit favorable prospects for application. Although there has been progress in the identification of biomarkers for the diagnosis, prognosis, activity and severity of sarcoidosis, specific and sensitive biomarkers have yet to be identified. This review outlines recent advancements in the molecular mechanisms and therapeutic strategies for the sarcoidosis.

Phenotypes and Endotypes in Sarcoidosis: Unraveling Prognosis and Disease Course

Sarcoidosis is a multi-system granulomatous disease of unknown etiology. In genetically susceptible individuals, the precipitating factors generate, via immunity mechanisms, a host granulomatous response. The granuloma, for unknown reasons thus far, may resolve or may persist and lead to organ damage and fibrosis. Infectious agents, occupational exposure, obesity, smoking and genetic factors are implicated in the pathogenesis of sarcoidosis. Macrophages are important in granuloma formation, and their M1/M2 phenotype is associated with the prognosis of the disease. CD4+ T helper cells play a central role in the pathogenesis of sarcoidosis. The major contributors appear to be Th1 and Th17.1 cells, whose microenvironmental behavior is dictated by the secretions of macrophages and dendritic cells. Higher levels of Th1 and Th17.1 cells are associated with chronic disease and resistance to corticosteroid treatment. In recent years, advances in the phenotyping of sarcoidosis with the help of HRCT, PET-CT and lung function tests have provided us with a better understanding of the disease. Genetic phenotyping performed by the GenPhenReSa consortium and the SAGA study has led to the recognition of new, distinct phenotypes. The reconstitution of dysregulated autophagy through persistent m-TORC-1 pathways may be a new treatment target in sarcoidosis.

The biological basis for current treatment strategies for granulomatous disease in common variable immunodeficiency

PURPOSE OF REVIEW

The pathogenesis of granulomatous disease in common variable immunodeficiency (CVID) is still largely unknown, which hampers effective treatment. This review describes the current knowledge on the pathogenesis of granuloma formation in CVID and the biological basis of the current treatment options.

RECENT FINDINGS

Histological analysis shows that T and B cells are abundantly present in the granulomas that are less well organized and are frequently associated with lymphoid hyperplasia. Increased presence of activation markers such as soluble IL-2 receptor (sIL-2R) and IFN-ɣ, suggest increased Th1-cell activity. Moreover, B-cell abnormalities are prominent in CVID, with elevated IgM, BAFF, and CD21low B cells correlating with granulomatous disease progression. Innate immune alterations, as M2 macrophages and neutrophil dysregulation, indicate chronic inflammation. Therapeutic regimens include glucocorticoids, DMARDs, and biologicals like rituximab.

SUMMARY

Our review links the biological context of CVID with granulomatous disease or GLILD to currently prescribed therapies and potential targeted treatments.

Extrapulmonary sarcoidosis

Sarcoidosis is a chronic disease of unknown origin that develops when a genetically susceptible host is exposed to an antigen, leading to an exuberant immune response characterized by granulomatous inflammation. Although lung involvement is almost universal as well as the leading cause of morbidity and mortality, virtually any organ can be affected. In particular, sarcoidosis of the heart, nervous system, and eyes can be devastating, leading to death, debilitation and blindness, and a multidisciplinary approach involving expert specialists is required for prompt diagnosis and appropriate treatment. Sarcoidosis of the skin can be disfiguring, thus posing a substantial psychologic and social impact on the patients. The diagnosis is often straightforward in the presence of compatible clinical manifestations in patients with biopsy-proven sarcoidosis, but is challenging when extrapulmonary signs/symptoms occur in isolation. Corticosteroids remain the first line therapy, with immunosuppressive or biologic agents being reserved to patients failing or experiencing side effects from steroids or developing refractory disease.

The immunopathogenesis of sarcoidosis

Sarcoidosis is a granulomatous multiorgan disease, thought to result from exposure to yet unidentified antigens in genetically susceptible individuals. The exaggerated inflammatory response that leads to granuloma formation is highly complex and involves the innate and adaptive immune system. Consecutive immunological studies using advanced technology have increased our understanding of aberrantly activated immune cells, mediators and pathways that influence the formation, maintenance and resolution of granulomas. Over the years, it has become increasingly clear that disease immunopathogenesis can only be understood if the clinical heterogeneity of sarcoidosis is taken into consideration, along with the distribution of immune cells in peripheral blood and involved organs. Most studies offer an immunological snapshot during disease course, while the cellular composition of both the circulation and tissue microenvironment may change over time. Despite these challenges, novel insights on the role of the immune system are continuously published, thus bringing the field forward. This review highlights current knowledge on the innate and adaptive immune responses involved in sarcoidosis pathogenesis, as well as the pathways involved in non-resolving disease and fibrosis development. Additionally, we describe proposed immunological mechanisms responsible for drug-induced sarcoid like reactions. Although many aspects of disease immunopathogenesis remain to be unraveled, the identification of crucial immune reactions in sarcoidosis may help identify new treatment targets. We therefore also discuss potential therapies and future strategies based on the latest immunological findings.

Utility of Mechanistic Target of Rapamycin Inhibitors in Cardiac Sarcoidosis

BACKGROUND

Cardiac sarcoidosis is an uncommon but potentially devastating manifestation of sarcoidosis, which is a multisystem inflammatory granulomatous disease. Although corticosteroids are the mainstay of treatment, given the number of complications associated with their long-term use, there is increasing interest in the use of steroid-sparing agents. Recent basic and translational studies have suggested a role for the mechanistic target of rapamycin (mTOR) pathway in cardiac sarcoidosis.

METHODS

We identified 4 patients treated at the Cedars-Sinai Cardiac Sarcoidosis Clinic who had active cardiac sarcoidosis and contraindications to corticosteroid intensification. We sought to evaluate the role of mechanistic target of mTOR inhibitors on the change in cardiac inflammation via cardiac 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging.

RESULTS

Of the 4 patients, 2 showed substantial improvement in cardiac inflammation on follow-up FDG-PET imaging after 6 months of treatment with an mTOR inhibitor but without corticosteroid intensification. There was a greater than 80% reduction in the cardiometabolic activity. The other 2 patients treated with an mTOR inhibitor had persistent evidence of cardiac inflammation on follow-up FDG-PET, necessitating an augmented treatment regimen.

DISCUSSION

This case series represents the first clinical use of mTOR inhibitors for cardiac sarcoidosis, and it suggests that these agents may have a role in the management of cardiac sarcoidosis.

Targeting cytokine networks in neuroinflammatory diseases

In neuroinflammatory diseases, systemic (blood-borne) leukocytes invade the central nervous system (CNS) and lead to tissue damage. A causal relationship between neuroinflammatory diseases and dysregulated cytokine networks is well established across several preclinical models. Cytokine dysregulation is also observed as an inadvertent effect of cancer immunotherapy, where it often leads to neuroinflammation. Neuroinflammatory diseases can be separated into those in which a pathogen is at the centre of the immune response and those of largely unknown aetiology. Here, we discuss the pathophysiology, cytokine networks and therapeutic landscape of 'sterile' neuroinflammatory diseases such as multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), neurosarcoidosis and immune effector cell-associated neurotoxicity syndrome (ICANS) triggered by cancer immunotherapy. Despite successes in targeting cytokine networks in preclinical models of neuroinflammation, the clinical translation of targeting cytokines and their receptors has shown mixed and often paradoxical responses.

Treatment of refractory cutaneous dermatomyositis with oral sirolimus

We present a single-centre retrospective case series of four patients with clinically amyopathic dermatomyositis from our institution who were treated with oral sirolimus after failing multiple other therapies. Three of our four patients achieved significant control of disease and were able to decrease their prednisone dose while on sirolimus. There were no clinically significant infections or new malignancies during sirolimus treatment in any of the patients.

[Position paper of the Austrian Society for Rheumatology and the Austrian Society for Pneumology on the diagnosis and treatment of sarcoidosis 2024]

In many cases sarcoidosis is a multisystemic disease that requires interdisciplinary medical cooperation in the diagnostics, treatment and medical care during follow-up. Due to the often chronic course, it is of utmost importance to include patients with their priorities and wishes at an early stage and extensively in disease management and to establish a shared decision making whenever possible. In the process of writing this joint position paper, the expert group on interstitial and orphan lung diseases of the Austrian Society for Pulmonology and the working group on rheumatological lung disorders of the Austrian Society for Rheumatology and Rehabilitation sought to include patient advocacy groups as well as experts for rare organ manifestations of sarcoidosis. This position paper is not only meant to reflect current scientific and clinical standards but should also focus the national expertise and by networking and exchange to be a first step to strengthen cooperation between stakeholders to ultimately improve care for patients with sarcoidosis.

Sarcoidosis versus Granulomatous and Lymphocytic Interstitial Lung Disease in Common Variable Immunodeficiency: A Comparative Review

Sarcoidosis and Granulomatous and Lymphocytic Interstitial Lung Diseases (GLILD) are two rare entities primarily characterised by the development of Interstitial Lung Disease (ILD) in the context of systemic immune dysregulation. These two conditions partially share the immunological background and pathologic findings, with granuloma as the main common feature. In this narrative review, we performed a careful comparison between sarcoidosis and GLILD, with an overview of their main similarities and differences, starting from a clinical perspective and ending with a deeper look at the immunopathogenesis and possible target therapies. Sarcoidosis occurs in immunocompetent individuals, whereas GLILD occurs in patients affected by common variable immunodeficiency (CVID). Moreover, peculiar extrapulmonary manifestations and radiological and histological features may help distinguish the two diseases. Despite that, common pathogenetic pathways have been suggested and both these disorders can cause progressive impairment of lung function and variable systemic granulomatous and non-granulomatous complications, leading to significant morbidity, reduced quality of life, and survival. Due to the rarity of these conditions and the extreme clinical variability, there are still many open questions concerning their pathogenesis, natural history, and optimal management. However, if studied in parallel, these two entities might benefit from each other, leading to a better understanding of their pathogenesis and to more tailored treatment approaches.

Humoral pathways of innate immune regulation in granuloma formation

The humoral arm of mammalian innate immunity regulates several molecular mechanisms involved in resistance to pathogens, inflammation, and tissue repair. Recent studies highlight the crucial role played by humoral mediators in granulomatous inflammation. However the molecular mechanisms linking the function of these soluble molecules to the initiation and maintenance of granulomas remain elusive. We propose that humoral innate immunity coordinates fundamental physiological processes in macrophages which, in turn, initiate activation and transformation events that enable granuloma formation. We discuss the involvement of humoral mediators in processes such as immune activation, phagocytosis, metabolism, and tissue remodeling, and how these can dictate macrophage functionality during granuloma formation. These advances present opportunities for discovering novel disease factors and developing targeted, more effective treatments for granulomatous diseases.

Sarcoidosis immunopathogenesis - a new concept of maladaptive trained immunity

Sarcoidosis is a chronic immune disease of unknown origin for which we still lack an immunological framework unifying causal agents, host factors, and natural history of disease. Here, we discuss the initial triggers of disease, and how myeloid cells drive granuloma formation and contribute to immunopathogenesis. We highlight recent advances in our understanding of innate immune memory and propose the hypothesis that maladaptive innate immune training connects previous environmental exposure to granuloma maintenance and expansion. Lastly, we consider how this hypothesis may open novel therapeutic avenues, while corticosteroids remain the front-line treatment.