Angela Rösen-Wolff

Novel STAT1 alleles in otherwise healthy patients with mycobacterial disease.

The transcription factor signal transducer and activator of transcription-1 (STAT1) plays a key role in immunity against mycobacterial and viral infections. Here, we characterize three human STAT1 germline alleles from otherwise healthy patients with mycobacterial disease. The previously reported L706S, like the novel Q463H and E320Q alleles, are intrinsically deleterious for both interferon gamma (IFNG)–induced gamma-activating factor–mediated immunity and interferon alpha (IFNA)–induced interferon-stimulated genes factor 3–mediated immunity, as shown in STAT1-deficient cells transfected with the corresponding alleles. Their phenotypic effects are however mediated by different molecular mechanisms, L706S affecting STAT1 phosphorylation and Q463H and E320Q affecting STAT1 DNA-binding activity. Heterozygous patients display specifically impaired IFNG-induced gamma-activating factor–mediated immunity, resulting in susceptibility to mycobacteria. Indeed, IFNA-induced interferon-stimulated genes factor 3–mediated immunity is not affected, and these patients are not particularly susceptible to viral disease, unlike patients homozygous for other, equally deleterious STAT1 mutations recessive for both phenotypes. The three STAT1 alleles are therefore dominant for IFNG-mediated antimycobacterial immunity but recessive for IFNA-mediated antiviral immunity at the cellular and clinical levels. These STAT1 alleles define two forms of dominant STAT1 deficiency, depending on whether the mutations impair STAT1 phosphorylation or DNA binding.

Biological properties and regulation of IL-10 related cytokines and their contribution to autoimmune disease and tissue injury

The IL-10 cytokine family has nine members, four of which are located in the IL10 cluster on chromosome 1q32. These cytokines are the immune regulatory cytokine IL-10 itself, and the IL-20 subfamily members IL-19, IL-20, and IL-24. IL-10 instructs innate and adaptive immune responses and limits pro-inflammatory responses in order to prevent tissue damage. The IL-20 subfamily members are involved in host defense mechanisms, particularly from epithelial cells and seem essential for tissue integrity. Dysregulation of IL-10 family cytokines results in inflammation and autoimmune disease. Here, we discuss cellular source, gene regulation, and receptor complexes of cytokines in the IL10 cluster and their contribution to autoimmune disease and tissue damage.

Increased susceptibility of a carrier of X-linked chronic granulomatous disease (CGD) to Aspergillus fumigatus infection associated with age-related skewing of lyonization.

Abstract Chronic granulomatous disease (CGD) is an inherited disorder characterized by the inability of phagocytes to generate normal amounts of superoxide (O2–), leaving patients susceptible to life-threatening infections. It was previously assumed that once carriers of the X-linked form of CGD were found to have 30% or more of functionally normal neutrophils, they would be free of risk for infection because the lyonization ratio was believed to be constant. Our report strongly contradicts this assumption. A 45-year-old X-CGD carrier had approximately 40% of normal neutrophils in her peripheral blood at age 21 years. Recently, she contracted a life-threatening pulmonary infection with Aspergillus fumigatus. After recovery, the ratio of normal-to-nonfunctional neutrophils was re-evaluated. She was found to have only 6–8% of normal neutrophils, suggesting that a striking decrease in the number of normal cells over the past 25 years was the reason for an increased susceptibility to Aspergillus infection. We conclude that age-related acquired skewing of the lyonization ratio can result in an increased susceptibility to life-threatening infections in X-CGD carriers.

Chronic non-bacterial osteomyelitis is associated with impaired Sp1 signaling, reduced IL10 promoter phosphorylation, and reduced myeloid IL-10 expression

Chronic non-bacterial osteomyelitis (CNO) is an auto-inflammatory disorder that affects the skeletal system. Interleukin (IL-)10 is an immune-modulatory cytokine that controls inflammation, and limits inflammatory cytokine responses. Dysregulation of IL-10 expression has been shown to result in autoimmune and infectious diseases. We investigated IL-10 expression by monocytic cells from CNO patients and controls. In response to stimulation with LPS, IL-10 expression from CNO monocytes was reduced (p<0.001). This was independent of IL10 promoter polymorphisms. Thus, we investigated Sp1 recruitment to the IL10 promoter and saw markedly reduced binding in CNO monocytes. This was accompanied with reduced phosphorylation of histone H3 serine 10 (H3S10), an activating epigenetic mark. Impaired recruitment of Sp1 to the IL10 promoter, and reduced H3S10 phosphorylation, may be a reflection of deficient MAPK signaling in CNO monocytes in response to LPS stimulation. Thus, we have discovered a mechanism that may be central in the pathophysiology of CNO.

Attenuated TLR4/MAPK signaling in monocytes from patients with CRMO results in impaired IL-10 expression.

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disorder of unknown origin. We previously demonstrated that monocytes from CRMO patients fail to express the immune-modulatory cytokine interleukin-10 (IL-10) in a chromatin dependent manner. Here, we demonstrate that attenuated extracellular-signal regulated kinase (ERK)1 and 2 signaling in response to TLR4 activation results in failure to induce IL-10 expression in monocytes from CRMO patients. Attenuated ERK1/2 activation results in 1) reduced levels of Sp-1, a transcription factor that induces IL-10 expression in monocytes, and 2) impaired H3S10 phosphorylation of the IL10 promoter, an activating epigenetic mark. The pro-inflammatory cytokines tumor necrosis factor (TNF)α and IL-6 are not negatively affected, resulting in an imbalance towards pro-inflammatory cytokines. Thus, impaired ERK1/2 signaling with subsequently reduced Sp-1 expression and H3S10 phosphorylation of the IL10 promoter may centrally contribute to the pathophysiology of CRMO.

Crosstalk of osteoblast and osteoclast precursors on mineralized collagen—towards an in vitro model for bone remodeling

Bone remodeling and, therefore, integration of implant materials require the coordinated regulation of osteoblast and osteoclast activity. This is why the in vitro evaluation of biomaterials for bone regeneration should involve not only the analysis of osteoblast differentiation but also the formation and differentiation of osteoclasts. In the present study, we applied a material made of mineralized collagen I that mimics extracellular bone matrix to establish a culture system, which allows the cocultivation of human monocytes and human mesenchymal stem cells (hMSCs), which were differentiated into osteoclast-like cells and osteoblasts, respectively. Both cell types were cultivated on membrane-like structures from mineralized collagen. Transwell inserts were used to spatially separate the cell types but allowed exchange of soluble factors. The osteoclastogenesis and osteogenic differentiation were evaluated by analysis of gene expression, determination of alkaline phosphatase (ALP), and tartrate-resistant acidic phosphatase (TRAP) activity. Furthermore, cell morphology was studied using scanning electron and transmission electron microscopy. Osteogenically induced hMSC showed an increased specific ALP activity as well as increased gene expression of gene coding for alkaline phosphatase (ALPL), when cocultivated with differentiating osteoclasts. Adipogenic differentiation of hMSCs was suppressed by the presence of osteoclasts as indicated by a major decrease in adipocyte cell number and a decrease in gene expression of adipogenic markers. The formation of multinucleated osteoclasts seems to be decreased in the presence of osteogenically induced hMSC as indicated by electron microscopic evaluation and determination of TRAP activity. However, gene expression of osteoclast markers was not decreased in coculture with osteogenically induced hMSC.

Periodic fever (TRAPS) caused by mutations in the TNFα receptor 1 (TNFRSF1A) gene of three German patients

Abstract: TNF‐receptor‐associated periodic syndrome (TRAPS) is a recently recognized disorder characterized by prolonged attacks of high fever and severe localized inflammation. TRAPS is caused by dominant mutations in the 55 kDa TNF receptor gene (TNFRSF1A). We here describe three German TRAPS patients of two families with Cys30→Arg and Thr50→Met mutations, respectively. Both mutations have already been observed before in other nonrelated families. The Thr50→Met amino acid exchange, caused by an ACG→ATG transition, has been reported in two other families of different ethnic background. The possibility that the ACG→ATG sequence alteration is a mutational hot spot causing TRAPS is discussed. Furthermore, we describe and discuss the symptoms of our patients, possible inducers of febrile attacks, and treatments which the patients had received when their diagnoses were still unknown.

Two German CINCA (NOMID) patients with different clinical severity and response to anti-inflammatory treatment

Chronic infantile neurologic, cutaneous, articular (CINCA) syndrome is characterized by fever, chronic meningitis, uveitis, sensorineural hearing loss, urticarial skin rash, and a deforming arthritis. In the CIAS1 gene of many but not all CINCA patients, disease‐associated mutations have been found recently. We here describe two such patients from Germany. One of them, a 3‐yr‐old boy, has a 1709A→G, Y570C, mutation, which has previously been described to cause CINCA syndrome. His clinical course is very severe and no satisfying response has been achieved even with high doses of local and systemic steroids. The other patient has a somewhat milder clinical course and considerable improvement could be accomplished with moderate and low doses of steroids. In her CIAS1 gene we have found a 1043C→T, T348M, mutation, which has only been detected in Muckle–Wells syndrome before. Our results suggest that the severity of symptoms in CINCA patients may be influenced by the underlying mutation in the CIAS1 gene. Furthermore, our observations support the view that CINCA syndrome and Muckle–Wells syndrome are essentially the same disease with different degrees of severity.

Periodic fever, mild arthralgias, and reversible moderate and severe organ inflammation associated with the V198M mutation in the CIAS1 gene in three German patients – expanding phenotype of CIAS1 related autoinflammatory syndrome

Abstract:  Dominant mutations in the CIAS1 gene cause a spectrum of autoinflammatory diseases such as familial cold autoinflammatory syndrome, FCAS, which is characterized by episodes of urticaria, arthralgia, fever and conjunctivitis after generalized exposure to cold. We here describe patients of two German families with the 592G→A, V198M mutation, which has been described to induce FCAS before. However, in our patients the clinical phenotype was very different from this disease. They never had urticaria, cold induced fever or conjunctivitis; instead the following symptoms occurred: Very regular periodic fever, irregular severe febrile episodes, relatively mild arthralgia, dry cough, cardiomyopathy, nephropathy and euthyroid thyroiditis all being reversible. We conclude that the clinical phenotype associated with mutations in the CIAS1 gene is much broader than assumed before.

Genetic architecture distinguishes systemic juvenile idiopathic arthritis from other forms of juvenile idiopathic arthritis: clinical and therapeutic implications

Objectives Juvenile idiopathic arthritis (JIA) is a heterogeneous group of conditions unified by the presence of chronic childhood arthritis without an identifiable cause. Systemic JIA (sJIA) is a rare form of JIA characterised by systemic inflammation. sJIA is distinguished from other forms of JIA by unique clinical features and treatment responses that are similar to autoinflammatory diseases. However, approximately half of children with sJIA develop destructive, long-standing arthritis that appears similar to other forms of JIA. Using genomic approaches, we sought to gain novel insights into the pathophysiology of sJIA and its relationship with other forms of JIA. Methods We performed a genome-wide association study of 770 children with sJIA collected in nine countries by the International Childhood Arthritis Genetics Consortium. Single nucleotide polymorphisms were tested for association with sJIA. Weighted genetic risk scores were used to compare the genetic architecture of sJIA with other JIA subtypes. Results The major histocompatibility complex locus and a locus on chromosome 1 each showed association with sJIA exceeding the threshold for genome-wide significance, while 23 other novel loci were suggestive of association with sJIA. Using a combination of genetic and statistical approaches, we found no evidence of shared genetic architecture between sJIA and other common JIA subtypes. Conclusions The lack of shared genetic risk factors between sJIA and other JIA subtypes supports the hypothesis that sJIA is a unique disease process and argues for a different classification framework. Research to improve sJIA therapy should target its unique genetics and specific pathophysiological pathways.