Aberrant Lipid Metabolism in Macrophages Is Associated with Granuloma Formation in Sarcoidosis.

Rationale: Chronic sarcoidosis is a complex granulomatous disease with limited treatment options that can progress over time. Understanding the molecular pathways contributing to disease would aid in new therapeutic development. Objectives: To understand whether macrophages from patients with nonresolving chronic sarcoidosis are predisposed to macrophage aggregation and granuloma formation and whether modulation of the underlying molecular pathways influence sarcoidosis granuloma formation. Methods: Macrophages were cultivated in vitro from isolated peripheral blood CD14+ monocytes and evaluated for spontaneous aggregation. Transcriptomics analyses and phenotypic and drug inhibitory experiments were performed on these monocyte-derived macrophages. Human skin biopsies from patients with sarcoidosis and a myeloid Tsc2-specific sarcoidosis mouse model were analyzed for validatory experiments. Measurements and Main Results: Monocyte-derived macrophages from patients with chronic sarcoidosis spontaneously formed extensive granulomas in vitro compared with healthy control participants. Transcriptomic analyses separated healthy and sarcoidosis macrophages and identified an enrichment in lipid metabolic processes. In vitro patient granulomas, sarcoidosis mouse model granulomas, and those directly analyzed from lesional patient skin expressed an aberrant lipid metabolism profile and contained increased neutral lipids. Conversely, a combination of statins and cholesterol-reducing agents reduced granuloma formation both in vitro and in vivo in a sarcoidosis mouse model. Conclusions: Together, our findings show that altered lipid metabolism in sarcoidosis macrophages is associated with its predisposition to granuloma formation and suggest cholesterol-reducing therapies as a treatment option in patients.

Whole exome sequencing of a German sarcoidosis family with four affected and one spontaneous remission case.

OBJECTIVES: To analyze genetic mechanisms triggering familial sarcoidosis, whole exome screening of a family of six persons with four cases of sarcoidosis and two healthy controls was performed integrating progressive and spontaneous remission cases and evaluating involved genetic alterations that could potentially determine the individual course of the disease. METHODS: Clinical diagnosis criteria in patients of the selected sarcoidosis family were according to American Thoracic Society/European Respiratory Society/World Association of Sarcoidosis and other Granulomatous Disorders guidelines [1]. Exome screening of four patients and the two intrafamilial healthy relatives was performed by a paired-end (2 × 100 bp) sequencing using a NovaSeq 6000 (Illumina, San Diego, CA). We then selected the gene variants considered pathogenic on the basis of a series of prediction software and present only in subjects affected by sarcoidosis of the family, after subtracting the common variations observed in healthy subjects. RESULTS: Four persons out of six family members were affected by sarcoidosis. 50 genes with uncommon in silico pathogenic variants could be identified that differentiated affected and healthy family members. One patient with sarcoidosis showed spontaneous remission whereas the remaining three patients required immunosuppressive treatment. Subtraction analysis revealed 18 genes that distinguished the three progressive cases from the patient with spontaneous remission. CONCLUSION: The genetic analysis of these cases with familial sarcoidosis identified several involved genes and functional pathways that could help to understand the basic mechanisms that determine the development of the disease and that discriminate spontaneously regressive and progressive forms.

Sarcoidosis and the mTOR, Rac1, and Autophagy Triad.

Sarcoidosis is an enigmatic multisystem disease characterized by the development and accumulation of granulomas: a compact collection of macrophages that have differentiated into epithelioid cells and which are associated with T helper (Th)1 and Th17 cells. Although no single causative factor has been shown to underlie sarcoidosis in humans, its etiology has been related to microbial, environmental, and genetic factors. We examine how these factors play a role in sarcoidosis pathogenesis. Specifically, we propose that dysfunction of mTOR, Rac1, and autophagy-related pathways not only hampers pathogen or nonorganic particle clearance but also participates in T cell and macrophage dysfunction, driving granuloma formation. This concept opens new avenues for potentially treating sarcoidosis and may serve as a blueprint for other granulomatous disorders.

Modeling Potential Autophagy Pathways in COVID-19 and Sarcoidosis.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and mainly affects the lungs. Sarcoidosis is an autoinflammatory disease characterized by the diffusion of granulomas in the lungs and other organs. Here, we discuss how the two diseases might involve some common mechanistic cellular pathways around the regulation of autophagy.

Identification and Characterization of an Exonic Duplication in PALB2 in a Man with Synchronous Breast and Prostate Cancer.

PALB2 (partner and localizer of BRCA2), as indicated by its name, is a BRCA2-interacting protein that plays an important role in homologous recombination (HR) and DNA double-strand break (DSB) repair. While pathogenic variants of PALB2 have been well proven to confer an increased risk of breast cancer, data on its involvement in prostate cancer (PrC) have not been clearly demonstrated. We investigated, using targeted next generation sequencing (NGS), a 59-year-old Caucasian man who developed synchronous breast and prostate cancers. This genetic investigation allowed to identify an intragenic germline heterozygous duplication in PALB2, implicating intronic repetitive sequences spanning exon 11. This variant was confirmed by multiplex ligation probe amplification (MLPA), and genomic breakpoints have been identified and characterized at the nucleotide level (c.3114-811_3202-1756dup) using an approach based on walking PCR, long range PCR, and Sanger sequencing. RT-PCR using mRNA extracted from lymphocytes and followed by Sanger sequencing revealed a tandem duplication r.3114_3201dup; p.(Gly1068Glufs * 14). This duplication results in the synthesis of a truncated, and most-likely, non-functional protein. These findings expand the phenotypic spectrum of PALB2 variants and may improve the yield of genetic diagnoses in this field.

Proposition of adjustments to the ACMG-AMP framework for the interpretation of MEN1 missense variants.

In 2015, the ACMG-AMP guidelines provided a general procedure for the objective and reproducible classification of genomic variants. While the benefits of this framework are of major importance, its adaptation for locus-specific use is needed. Multiple Endocrine Neoplasia type 1 (MEN1) occurs due to inactivating mutations in the tumour suppressor gene MEN1, including 20% of missense variants. The classification of these variants may be extremely challenging. Here, we compared the interpretation of the 122 MEN1 missense variants, identified in the French population over the past 15 years by the TENGEN network (French oncogenetics network of neuroendocrine tumors) versus by using the ACMG-AMP guidelines, and analyzed the causes of discordance. A total of 59.8% of missense variants were termed as (likely)-pathogenic variants by TENGEN versus only 28.7% using ACMG-AMP guidelines. Actually, 53.4% (39/73) of TENGEN (likely)-pathogenic variants were declassified in variant of uncertain significance (VUS) by using ACMG-AMP guidelines, thereby affecting the clinical management of patients and their families. Twenty of these ACMG-AMP VUS were found in patients with a clinically authentic MEN1 disease. Here, TENGEN proposes adjustments to the ACMG-AMP framework for the interpretation of MEN1 missense variants. These propositions merge both the classification systems, and are particularly interesting, as MEN1 is included in the ACMG secondary findings list for reporting in clinical genomic sequencing.

Paediatric sarcoidosis.

Paediatric sarcoidosis is an extremely rare disease characterized by a granulomatous inflammation. The estimated incidence is 0.6-1.02/100,000 children, but in the absence of international registers, the disease is probably under-reported. Its pathophysiologic basis is not clearly understood but the current hypothesis is a combination of a genetic predisposition and an environmental exposure that could be either organic or mineral. Contrary to adult forms of the disease, general symptoms are often at the forefront at diagnosis. In its most frequent form, paediatric sarcoidosis is a multi-organ disorder affecting preferentially the lungs, the lymphatic system and the liver, but all organs can be affected. This review aims to provide an overview of current knowledge on sarcoidosis in children, providing a summary of the data available from cohort studies on the presentation, the management and the evolution of the disease in this specific population.

G908R NOD2 variant in a family with sarcoidosis.

BACKGROUND: Sarcoidosis is a systemic disease characterized by the formation of immune granulomas in various organs, mainly the lungs and the lymphatic system. Exaggerated granulomatous reaction might be triggered in response to unidentified antigens in individuals with genetic susceptibility. The present study aimed to determine the genetic variants implicated in a familial case of sarcoidosis. METHODS: Sarcoidosis presentation and history, NOD2 profile, NF-κB and cytokine production in blood monocytes/macrophages were evaluated in individuals from a family with late appearance of sarcoidosis. RESULTS: In the present study, we report a case of familial sarcoidosis with typical thoracic sarcoidosis and carrying the NOD2 2722G > C variant. This variant is associated with the presence of three additional SNPs for the IL17RA, KALRN and EPHA2 genes, which discriminate patients expressing the disease from others. Despite a decrease in NF-κB activity, IL-8 and TNF-A mRNA levels were increased at baseline and in stimulated conditions. CONCLUSIONS: Combination of polymorphisms in the NOD2, IL17RA, EPHA2 and KALRN genes could play a significant role in the development of sarcoidosis by maintaining a chronic pro-inflammatory status in macrophages.

Granulomatous lung inflammation is nanoparticle type-dependent.

BACKGROUND: Nanoparticles are increasingly suspected as a strong etiologic factor of granuloma formation. AIM OF THE STUDY: The aim of our study was to compare lung inflammatory response and histology changes following exposure of mice to two widely used nanoparticles: carbon nanotubes (MWCNT) and cadmium-based nanoparticles (QDOT705) in an attempt to better our understanding of granulomatous inflammation. MATERIALS AND METHODS: Various groups of mice were included: control mice and mice that were intranasally instilled with QDOT or MWCNT. At defined time points post-challenge, bronchoalveolar lavages (BALs) and lung tissues were collected to study inflammatory and histologic changes. RESULTS: Analyses of lung BAL fluids and tissues of nanoparticles-challenged mice in comparison to controls found: (1) increased cellularity in BALs, (2) increase of total protein concentration, LDH activity and proteolytic activity in BALs; (3) patchy granulomas, (4) macrophages, CD3 ± T, Treg and B cell infiltration in granulomatous areas; and (5) altered regulation of key inflammatory mediators and receptors. Importantly, these changes were nanoparticle type-dependent. CONCLUSION: Our work enhances understanding of nanoparticles-induced lung inflammatory and histological changes that result in granuloma formation. We provide compelling evidence that not only exposure to nanoparticles leads to granulomatous lung inflammation, but the severity of this latter is nanostructure type-dependent. Of importance, while nanotechnology has the potential to revolutionize various fields including medicine, nanoparticles form the potential for an entirely new lung health risk that it is necessary to take seriously into consideration by setting up and/or reinforcing adequate safety measures.

Higher risk of death among MEN1 patients with mutations in the JunD interacting domain: a Groupe d'etude des Tumeurs Endocrines (GTE) cohort study.

Multiple endocrine neoplasia syndrome type 1 (MEN1), which is secondary to mutation of the MEN1 gene, is a rare autosomal-dominant disease that predisposes mutation carriers to endocrine tumors. Although genotype-phenotype studies have so far failed to identify any statistical correlations, some families harbor recurrent tumor patterns. The function of MENIN is unclear, but has been described through the discovery of its interacting partners. Mutations in the interacting domains of MENIN functional partners have been shown to directly alter its regulation abilities. We report on a cohort of MEN1 patients from the Groupe d'étude des Tumeurs Endocrines. Patients with a molecular diagnosis and a clinical follow-up, totaling 262 families and 806 patients, were included. Associations between mutation type, location or interacting factors of the MENIN protein and death as well as the occurrence of MEN1-related tumors were tested using a frailty Cox model to adjust for potential heterogeneity across families. Accounting for the heterogeneity across families, the overall risk of death was significantly higher when mutations affected the JunD interacting domain (adjusted HR = 1.88: 95%-CI = 1.15-3.07). Patients had a higher risk of death from cancers of the MEN1 spectrum (HR = 2.34; 95%-CI = 1.23-4.43). This genotype-phenotype correlation study confirmed the lack of direct genotype-phenotype correlations. However, patients with mutations affecting the JunD interacting domain had a higher risk of death secondary to a MEN1 tumor and should thus be considered for surgical indications, genetic counseling and follow-up.

Novel KCNQ2 and KCNQ3 mutations in a large cohort of families with benign neonatal epilepsy: first evidence for an altered channel regulation by syntaxin-1A.

Mutations in the KCNQ2 and KCNQ3 genes encoding for Kv 7.2 (KCNQ2; Q2) and Kv 7.3 (KCNQ3; Q3) voltage-dependent K(+) channel subunits, respectively, cause neonatal epilepsies with wide phenotypic heterogeneity. In addition to benign familial neonatal epilepsy (BFNE), KCNQ2 mutations have been recently found in families with one or more family members with a severe outcome, including drug-resistant seizures with psychomotor retardation, electroencephalogram (EEG) suppression-burst pattern (Ohtahara syndrome), and distinct neuroradiological features, a condition that was named "KCNQ2 encephalopathy." In the present article, we describe clinical, genetic, and functional data from 17 patients/families whose electroclinical presentation was consistent with the diagnosis of BFNE. Sixteen different heterozygous mutations were found in KCNQ2, including 10 substitutions, three insertions/deletions and three large deletions. One substitution was found in KCNQ3. Most of these mutations were novel, except for four KCNQ2 substitutions that were shown to be recurrent. Electrophysiological studies in mammalian cells revealed that homomeric or heteromeric KCNQ2 and/or KCNQ3 channels carrying mutant subunits with newly found substitutions displayed reduced current densities. In addition, we describe, for the first time, that some mutations impair channel regulation by syntaxin-1A, highlighting a novel pathogenetic mechanism for KCNQ2-related epilepsies.

Complex mosaic CDKL5 deletion with two distinct mutant alleles in a 4-year-old girl.

Mutations of the CDKL5 gene cause early epileptic encephalopathy. Patients manifest refractory epilepsy, beginning before the age of 3 months, which is associated with severe psychomotor delay and features that overlap with Rett syndrome. We report here a patient with mosaicism for CDKL5 exonic deletion, with the presence of two mutant alleles. The affected 4-year-old girl presented with infantile spasms, beginning at the age of 9 months, but subsequent progression of the disease was consistent with the classical CDKL5-related phenotype. A deletion of exons 17 and 18 was suspected on the basis of Multiplex Ligation Probe Amplification analysis, but unexpected results for cDNA analysis, which showed the presence of an abnormal transcript with the deletion of exon 18 only, led us to suspect that two distinct events might have occurred. We used custom array-CGH to determine the size and breakpoints of these deletions. Exon 18 was deleted from one of the abnormal alleles, and exon 17 was deleted from the other. A Fork Stalling and Template Switching (FoSTeS) mechanism was proposed to explain the two events, given the presence of regions of microhomology at the breakpoints. We propose here an original involvement of the FoSTeS mechanism to explain the co-occurrence of these two events in the CDKL5 gene in a single patient. This patient highlights the difficulties involved in the detection of such abnormalities, particularly when they occur in a mosaic state and involve two distinct mutational events in a single gene.

Overview of the Genetic Causes of Hereditary Breast and Ovarian Cancer Syndrome in a Large French Patient Cohort.

The use of multigene panel testing for patients with a predisposition to Hereditary Breast and Ovarian Cancer syndrome (HBOC) is increasing as the identification of mutations is useful for diagnosis and disease management. Here, we conducted a retrospective analysis of BRCA1/2 and non-BRCA gene sequencing in 4630 French HBOC suspected patients. Patients were investigated using a germline cancer panel including the 13 genes defined by The French Genetic and Cancer Group (GGC)-Unicancer. In the patients analyzed, 528 pathogenic and likely pathogenic variants (P/LP) were identified, including BRCA1 (n = 203, 38%), BRCA2 (n = 198, 37%), PALB2 (n = 46, 9%), RAD51C (n = 36, 7%), TP53 (n = 16, 3%), and RAD51D (n = 13, 2%). In addition, 35 novel (P/LP) variants, according to our knowledge, were identified, and double mutations in two distinct genes were found in five patients. Interestingly, retesting a subset of BRCA1/2-negative individuals with an expanded panel produced clinically relevant results in 5% of cases. Additionally, combining in silico (splicing impact prediction tools) and in vitro analyses (RT-PCR and Sanger sequencing) highlighted the deleterious impact of four candidate variants on splicing and translation. Our results present an overview of pathogenic variations of HBOC genes in the southeast of France, emphasizing the clinical relevance of cDNA analysis and the importance of retesting BRCA-negative individuals with an expanded panel.

French recommendations for the diagnosis and management of lymphangioleiomyomatosis.

BACKGROUND: The present article is an English-language version of the French National Diagnostic and Care Protocol, a pragmatic tool to optimize and harmonize the diagnosis, care pathway, management and follow-up of lymphangioleiomyomatosis in France. METHODS: Practical recommendations were developed in accordance with the method for developing a National Diagnosis and Care Protocol for rare diseases of the Haute Autorité de Santé and following international guidelines and literature on lymphangioleiomyomatosis. It was developed by a multidisciplinary group, with the help of patient representatives and of RespiFIL, the rare disease network on respiratory diseases. RESULTS: Lymphangioleiomyomatosis is a rare lung disease characterised by a proliferation of smooth muscle cells that leads to the formation of multiple lung cysts. It occurs sporadically or as part of a genetic disease called tuberous sclerosis complex (TSC). The document addresses multiple aspects of the disease, to guide the clinicians regarding when to suspect a diagnosis of lymphangioleiomyomatosis, what to do in case of recurrent pneumothorax or angiomyolipomas, what investigations are needed to make the diagnosis of lymphangioleiomyomatosis, what the diagnostic criteria are for lymphangioleiomyomatosis, what the principles of management are, and how follow-up can be organised. Recommendations are made regarding the use of pharmaceutical specialties and treatment other than medications. CONCLUSION: These recommendations are intended to guide the diagnosis and practical management of pulmonary lymphangioleiomyomatosis.

Alpha cell-specific Men1 ablation triggers the transdifferentiation of glucagon-expressing cells and insulinoma development.

BACKGROUND & AIMS: The tumor suppressor menin is recognized as a key regulator of pancreatic islet development, proliferation, and beta-cell function, whereas its role in alpha cells remains poorly understood. The purpose of the current study was to address this issue in relation to islet tumor histogenesis. METHODS: We generated alpha cell-specific Men1 mutant mice with Cre/loxP technology and carried out analyses of pancreatic lesions developed in the mutant mice during aging. RESULTS: We showed that, despite the alpha-cell specificity of the GluCre transgene, both glucagonomas and a large amount of insulinomas developed in mutant mice older than 6 months, accompanied by mixed islet tumors. Interestingly, the cells sharing characteristics of both alpha and beta cells were identified shortly after the appearance of menin-deficient alpha cells but well before the tumor onset. Using a genetic cell lineage tracing analysis, we demonstrated that insulinoma cells were directly derived from transdifferentiating glucagon-expressing cells. Furthermore, our data indicated that the expression of Pdx1, MafA, Pax4, and Ngn3 did not seem to be required for the initiation of this transdifferentiation. CONCLUSIONS: Our work shows cell transdifferentiation as a novel mechanism involved in islet tumor development and provides evidence showing that menin regulates the plasticity of differentiated pancreatic alpha cells in vivo, shedding new light on the mechanisms of islet tumorigenesis.

Clinical aspects of multiple endocrine neoplasia type 1.

Multiple endocrine neoplasia type 1 (MEN1) is a rare syndrome characterized by the co-occurrence of primary hyperparathyroidism, duodenopancreatic neuroendocrine tumours (NETs) and/or pituitary adenomas. MEN1 can predispose patients to other endocrine and non-endocrine tumours, such as cutaneous tumours, central nervous system tumours and breast cancer. Endocrine tumours in patients with MEN1 differ from sporadic tumours in that they have a younger age at onset, present as multiple tumours in the same organ and have a different clinical course. Therefore, patients with overt MEN1 and those who carry a MEN1 mutation should be offered tailored biochemical and imaging screening to detect tumours and evaluate their progression over time. Fortunately, over the past 10 years, knowledge about the clinical phenotype of these tumours has markedly progressed, thanks to the implementation of national registries, particularly in France and the Netherlands. This Review provides an update on the clinical management of MEN1-related tumours. Epidemiology, the clinical picture, diagnostic work-up and the main lines of treatment for MEN1-related tumours are summarized. Controversial therapeutic aspects and issues that still need to be addressed are also discussed. Moreover, special attention is given to MEN1 manifestations in children and adolescents.

Identification and Characterization of New Alu Element Insertion in the BRCA1 Exon 14 Associated with Hereditary Breast and Ovarian Cancer.

Hereditary breast and ovarian cancer syndrome (HBOC) is an autosomal dominant cancer predisposition syndrome characterized by an increased risk of breast and ovarian cancers. Germline pathogenic variants in BRCA1 are found in about 7-10% of all familial breast cancers and 10% of ovarian cancers. Alu elements are the most abundant mobile DNA element in the human genome and are known to affect the human genome by different mechanisms leading to human disease. We report here the detection, by next-generation sequencing (NGS) analysis coupled with a suitable bioinformatics pipeline, of an AluYb8 element in exon 14 of the BRCA1 gene in a family with HBOC history first classified as BRCA-negative by Sanger sequencing and first NGS analysis. The c.4475_c.4476insAluYb8 mutation impacts splicing and induces the skipping of exon 14. As a result, the produced mRNA contains a premature stop, leading to the production of a short and likely non-functional protein (pAla1453Glyfs*10). Overall, our study allowed us to identify a novel pathogenic variant in BRCA1 and showed the importance of bioinformatics tool improvement and versioning.

Autophagy and Mitophagy-Related Pathways at the Crossroads of Genetic Pathways Involved in Familial Sarcoidosis and Host-Pathogen Interactions Induced by Coronaviruses.

Sarcoidosis is a multisystem disease characterized by the development and accumulation of granulomas, the hallmark of an inflammatory process induced by environmental and/or infectious and or genetic factors. This auto-inflammatory disease mainly affects the lungs, the gateway to environmental aggressions and viral infections. We have shown previously that genetic predisposition to sarcoidosis occurring in familial cases is related to a large spectrum of pathogenic variants with, however, a clustering around mTOR (mammalian Target Of Rapamycin)-related pathways and autophagy regulation. The context of the COVID-19 pandemic led us to evaluate whether such genetic defects may increase the risk of a severe course of SARS-CoV2 infection in patients with sarcoidosis. We extended a whole exome screening to 13 families predisposed to sarcoidosis and crossed the genes sharing mutations with the list of genes involved in the SARS-CoV2 host-pathogen protein-protein interactome. A similar analysis protocol was applied to a series of 100 healthy individuals. Using ENRICH.R, a comprehensive gene set enrichment web server, we identified the functional pathways represented in the set of genes carrying deleterious mutations and confirmed the overrepresentation of autophagy- and mitophagy-related functions in familial cases of sarcoidosis. The same protocol was applied to the set of genes common to sarcoidosis and the SARS-CoV2-host interactome and found a significant enrichment of genes related to mitochondrial factors involved in autophagy, mitophagy, and RIG-I-like (Retinoic Acid Inducible Gene 1) Receptor antiviral response signaling. From these results, we discuss the hypothesis according to which sarcoidosis is a model for studying genetic abnormalities associated with host response to viral infections as a consequence of defects in autophagy and mitophagy processes.

Sarcoidosis: A Clinical Overview from Symptoms to Diagnosis.

Sarcoidosis is a multi-system disease of unknown etiology characterized by the formation of granulomas in various organs. It affects people of all ethnic backgrounds and occurs at any time of life but is more frequent in African Americans and Scandinavians and in adults between 30 and 50 years of age. Sarcoidosis can affect any organ with a frequency varying according to ethnicity, sex and age. Intrathoracic involvement occurs in 90% of patients with symmetrical bilateral hilar adenopathy and/or diffuse lung micronodules, mainly along the lymphatic structures which are the most affected system. Among extrapulmonary manifestations, skin lesions, uveitis, liver or splenic involvement, peripheral and abdominal lymphadenopathy and peripheral arthritis are the most frequent with a prevalence of 25-50%. Finally, cardiac and neurological manifestations which can be the initial manifestation of sarcoidosis, as can be bilateral parotitis, nasosinusal or laryngeal signs, hypercalcemia and renal dysfunction, affect less than 10% of patients. The diagnosis is not standardized but is based on three major criteria: a compatible clinical and/or radiological presentation, the histological evidence of non-necrotizing granulomatous inflammation in one or more tissues and the exclusion of alternative causes of granulomatous disease. Certain clinical features are considered to be highly specific of the disease (e.g., Löfgren's syndrome, lupus pernio, Heerfordt's syndrome) and do not require histological confirmation. New diagnostic guidelines were recently published. Specific clinical criteria have been developed for the diagnosis of cardiac, neurological and ocular sarcoidosis. This article focuses on the clinical presentation and the common differentials that need to be considered when appropriate.