Acquired immune resistance is associated with interferon signature and modulation of KLF6/c-MYB transcription factors in myeloid leukemia.

Resistance to immunity is associated with the selection of cancer cells with superior capacities to survive inflammatory reactions. Here, we tailored an ex vivo immune selection model for acute myeloid leukemia (AML) and isolated the residual subpopulations as "immune-experienced" AML (ieAML) cells. We confirmed that upon surviving the immune reactions, the malignant blasts frequently decelerated proliferation, displayed features of myeloid differentiation and activation, and lost immunogenicity. Transcriptomic analyses revealed a limited number of commonly altered pathways and differentially expressed genes in all ieAML cells derived from distinct parental cell lines. Molecular signatures predominantly associated with interferon and inflammatory cytokine signaling were enriched in the AML cells resisting the T-cell-mediated immune reactions. Moreover, the expression and nuclear localization of the transcription factors c-MYB and KLF6 were noted as the putative markers for immune resistance and identified in subpopulations of AML blasts in the patients' bone marrow aspirates. The immune modulatory capacities of ieAML cells lasted for a restricted period when the immune selection pressure was omitted. In conclusion, myeloid leukemia cells harbor subpopulations that can adapt to the harsh conditions established by immune reactions, and a previous "immune experience" is marked with IFN signature and may pave the way for susceptibility to immune intervention therapies.

Allele-specific antisense oligonucleotides for the treatment of BEST1-related dominantly inherited retinal diseases: An in vitro model.

Retinal dystrophies are a common health problem worldwide that are currently incurable due to the inability of retinal cells to regenerate. Inherited retinal diseases (IRDs) are a diverse group of disorders characterized by progressive vision loss caused by photoreceptor cell dysfunction. The eye has always been an attractive organ for the development of novel therapies due to its independent access to the systemic pathway. Moreover, anti-sense oligonucleotides (ASOs), which facilitate manipulation of unwanted mRNAs via degradation or splicing, are undergoing rapid development and have been clinically deployed for the treatment of several diseases. The primary aim of this study was to establish a reliable in vitro model utilizing induced photoreceptor-like cells (PRCs) for assessing the efficacy and safety of ASOs targeting the BEST1 gene. Despite advances in gene therapy, effective treatments for a broad range of IRDs remain limited. An additional aim was to develop an in vitro model for evaluating RNA-based therapeutics, specifically ASOs, for the treatment in IRDs. Firstly, a cell culture model was established by induction of PRCs from dermal fibroblasts via direct programming. The induced PRCs were characterized at both the transcriptomic and protein level. Then, a common single nucleotide polymorphism (SNP) was identified in the BEST1 gene (rs1800007) for targeting with ASOs. ASOs were designed using the GapmeR strategy to target multiple alleles of this SNP, which is potentially suitable for a large proportion of the population. The efficacy and possible off-target effects of these ASOs were also analyzed in the induced PRC model. The findings show that the selected ASOs achieved allele-specific mRNA degradation with virtually no off-target effects on the global transcriptome profile, indicating their potential as safe and effective therapeutic agents. The presented in vitro model is a valuable platform for testing personalized IRD treatments and should inspire further research on RNA-based therapeutics. To the best of our knowledge this study is the first to test RNA-based therapeutics involving the use of ASOs in an induced PRC model. Based on the present findings, it will be possible to establish an ex vivo disease model using dermal fibroblast samples from affected individuals. In other words, the disease model and the ASOs that were successfully designed in this study can serve as a useful platform for the testing of personalized treatments for IRDs.

A novel GRK2 variant in a patient with Jeune asphyxiating thoracic dysplasia accompanied by Morgagni hernia.

Skeletal ciliopathies constitute a subgroup of ciliopathies characterized by various skeletal anomalies arising from mutations in genes impacting cilia, ciliogenesis, intraflagellar transport process, or various signaling pathways. Short-rib thoracic dysplasias, previously known as Jeune asphyxiating thoracic dysplasia (ATD), stand out as the most prevalent and prototypical form of skeletal ciliopathies, often associated with semilethality. Recently, pathogenic variants in GRK2, a subfamily of mammalian G protein-coupled receptor kinases, have been identified as one of the underlying causes of Jeune ATD. In this study, we report a new patient with Jeune ATD, in whom exome sequencing revealed a novel homozygous GRK2 variant, and we review the clinical features and radiographic findings. In addition, our findings introduce Morgagni hernia and an organoaxial-type rotation anomaly of the stomach and midgut malrotation for the first time in the context of this recently characterized GRK2-related skeletal ciliopathy.

A novel biallelic CRIPT variant in a patient with short stature, microcephaly, and distinctive facial features.

Primordial dwarfism (PD) is one of a highly heterogeneous group of disorders characterized by severe prenatal/postnatal growth restriction. Defects in various pathways such as DNA repair mechanism, impaired centrioles, abnormal IGF expression, and spliceosomal machinery may cause PD including Seckel syndrome, Silver-Russell syndrome. Microcephalic osteodysplastic primordial dwarfism (MOPD) types I/III, II, and Meier-Gorlin syndrome. In recent years with the wide application of exome sequencing (ES) in the field of PD, new genes involved in novel pathways causing new phenotypes have been identified. Pathogenic variants in CRIPT (MIM# 604594) encoding cysteine-rich PDZ domain-binding protein have recently been described in patients with PD with a unique phenotype. This phenotype is characterized by prenatal/postnatal growth restriction, facial dysmorphism, ocular abnormalities, and ectodermal findings such as skin lesions with hyper/hypopigmented patchy areas and hair abnormalities. To our knowledge, only three patients with homozygous or compound heterozygous variants in CRIPT have been reported so far. Here, we report on a male patient who presented with profound prenatal/postnatal growth restriction, developmental delay, dysmorphic facial features, and skin lesions along with the findings of bicytopenia and extensive retinal pigmentation defect. A novel truncating homozygous variant c.7_8delTG; p.(Cys3Argfs*4) was detected in CRIPT with the aid of ES. With this report, we further expand the mutational and clinical spectrum of this rare entity.

Effector Th1 cells under PD-1 and CTLA-4 checkpoint blockade abrogate the upregulation of multiple inhibitory receptors and by-pass exhaustion.

Immune checkpoint inhibitor (ICI) immunotherapy relies on the restoration of T-cell functions. The ICI receptors are not only found on exhausted T cells but also upregulated upon activation and reach high levels on effector T cells. In an ex vivo model, this study explored the consequences of PD-1 and cytotoxic T-lymphocyte antigen (CTLA-4) blockade applied during specific time frames of T-cell stimulation that coincide with distinct functional phases in type 1 helper T (Th1) cells. When applied at an early stimulation stage, the checkpoint blockade interfered with the upregulation of multiple inhibitory receptors such as PD-1, LAG3, TIM-3 and CTLA-4. Moreover, extension of the blockade period restricted the hyporesponsiveness in T cells. Alternatively, a short-term ICI treatment was advantageous when applied at late time frames of Th1 cell stimulation. Here, a transition phase from effector to exhausted state, which coincided with the late time frames of Th1 stimulation, was clearly determined together with the transcriptomics data demonstrating the initiation of significant alterations in metabolic pathways, genetic information processes, effector and exhaustion specific pathways. Applied in this transition phase, PD-1 and/or CTLA-4 blockade downregulated the inhibitory receptors which were already present on the effector Th1 cells, potentially through endocytic pathways. Therefore, the efficacy of ICI therapy was modulated by the functional status of T cells and can be improved by modifying the timing and duration of PD-1 and CTLA-4 blockade. In conclusion, the ICI therapy not only supports the reactivation of T cells but can also constrain de novo exhaustion.

Small cell lung cancer stem cells display mesenchymal properties and exploit immune checkpoint pathways in activated cytotoxic T lymphocytes.

Small cell lung cancer (SCLC) is an aggressive tumor type with early dissemination and distant metastasis capacity. Even though optimal chemotherapy responses are observed initially in many patients, therapy resistance is almost inevitable. Accordingly, SCLC has been regarded as an archetype for cancer stem cell (CSC) dynamics. To determine the immune-modulatory influence of CSC in SCLC, this study focused on the characterization of CD44+CD90+ CSC-like subpopulations in SCLC. These cells displayed mesenchymal properties, differentiated into different lineages and further contributed to CD8+ cytotoxic T lymphocytes (CTL) responses. The interaction between CD44+CD90+ CSC-like cells and T cells led to the upregulation of checkpoint molecules PD-1, CTLA-4, TIM-3, and LAG3. In the patient-derived lymph nodes, CD44+ SCLC metastases were also observed with T cells expressing PD-1, TIM-3, or LAG3. Proliferation and IFN-γ expression capacity of TIM-3 and LAG3 co-expressing CTLs are adversely affected over long-time co-culture with CD44+CD90+ CSC-like cells. Moreover, especially through IFN-γ secreted by the T cells, the CSC-like SCLC cells highly expressed PD-L1 and PD-L2. Upon a second encounter with immune-experienced, IFN-γ-stimulated CSC-like SCLC cells, both cytotoxic and proliferation capacities of T cells were hampered. In conclusion, our data provide evidence for the superior potential of the SCLC cells with stem-like and mesenchymal properties to gain immune regulatory capacities and cope with cytotoxic T cell responses. With their high metastatic and immune-modulatory assets, the CSC subpopulation in SCLC may serve as a preferential target for checkpoint blockade immunotherapy .

Identification of a shared genetic risk locus for Kawasaki disease and immunoglobulin A vasculitis by a cross-phenotype meta-analysis.

OBJECTIVES: Combining of genomic data of different pathologies as a single phenotype has emerged as a useful strategy to identify genetic risk loci shared among immune-mediated diseases. Our study aimed to increase our knowledge of the genetic contribution to Kawasaki disease (KD) and IgA vasculitis (IgAV) by performing the first comprehensive large-scale analysis on the genetic overlap between them. METHODS: A total of 1190 vasculitis patients and 11 302 healthy controls were analysed. First, in the discovery phase, genome-wide data of 405 KD patients and 6252 controls and 215 IgAV patients and 1324 controls, all of European origin, were combined using an inverse variance meta-analysis. Second, the top associated polymorphisms were selected for replication in additional independent cohorts (570 cases and 3726 controls). Polymorphisms with P-values ≤5 × 10-8 in the global IgAV-KD meta-analysis were considered as shared genetic risk loci. RESULTS: A genetic variant, rs3743841, located in an intron of the NAGPA gene, reached genome-wide significance in the cross-disease meta-analysis (P = 8.06 × 10-10). Additionally, when IgAV was individually analysed, a strong association between rs3743841 and this vasculitis was also evident [P = 1.25 × 10-7; odds ratio = 1.47 (95% CI 1.27, 1.69)]. In silico functional annotation showed that this polymorphism acts as a regulatory variant modulating the expression levels of the NAGPA and SEC14L5 genes. CONCLUSION: We identified a new risk locus with pleiotropic effects on the two childhood vasculitides analysed. This locus represents the strongest non-HLA signal described for IgAV to date.

Investigation of Genetic Causes in a Developmental Disorder: Oculoauriculovertebral Spectrum.

OBJECTIVE: Oculoauriculovertebral spectrum (OAVS) is a genetically and clinically heterogeneous disorder that occurs due to a developmental field defect of the first and second pharyngeal arches. Even though recent whole exome sequencing studies (WES) have led to identification of several genes associated with this spectrum in a subset of individuals, complete pathogenesis of OAVS remains unsolved. In this study, molecular genetic etiology of OAVS was systematically investigated. DESIGN/SETTING/PATIENTS: A cohort of 23 Turkish patients with OAVS, referred to Hacettepe University Hospital, Department of Pediatric Genetics from 2008 to 2018, was included in this study. Minimal diagnostic criteria for OAVS were considered as unilateral microtia or hemifacial microsomia with preauricular skin tag. The cohort was clinically reevaluated for craniofacial and extracranial findings. Molecular etiology was investigated using candidate gene sequencing following copy number variant (CNV) analysis. WES was also performed for 2 of the selected patients. RESULTS: Patients in the study cohort presented similar demographic and phenotypic characteristics to previously described patients in the literature except for a higher frequency of bilaterality, cardiac findings, and intellectual disability/developmental delay. CNV analysis revealed a possible genetic etiology for 3 patients (13%). Additional WES in 1 of the 2 patients uncovered a novel heterozygous nonsense variant in Elongation factor Tu GTP-binding domain-containing 2 (EFTUD2) causing mandibulofacial dysostosis with microcephaly (MFDM), which clinically overlaps with OAVS. CONCLUSION: Detailed clinical evaluation for any patient with OAVS is recommended due to a high rate of accompanying systemic findings. We further expand the existing genetic heterogeneity of OAVS by identifying several CNVs and a phenotypically overlapping disorder, MFDM.

CD66b+ monocytes represent a proinflammatory myeloid subpopulation in cancer.

Myeloid-derived suppressor cells (MDSC) populate the peripheral blood and contribute to immune regulation in cancer. However, there is limited knowledge on the myeloid cell types with proinflammatory capacities that may serve as opponents of MDSC. In the circulation of cancer patients, a monocyte subpopulation was identified with a specific immunophenotype and transcriptomic signature. They were predominantly CD14+CD33hiCD16-/+HLA-DR+/hi cells that typically expressed CD66b. In accordance with the transcriptomics data, NALP3, LOX-1 and PAI-1 levels were also significantly upregulated. The CD66b+ monocytes displayed high phagocytic activity, matrix adhesion and migration, and provided costimulation for T cell proliferation and IFN-γ secretion; thus, they did not suppress T cell responses. Irrespective of clinical stage, they were identified in various cancers. In conclusion, the CD66b+ monocytes represent a novel myeloid subpopulation which is devoid of immune regulatory influences of cancer and displays enhanced proinflammatory capacities.

Expanding the phenotypic spectrum of TNFRSF11A-associated dysosteosclerosis: a case with intracranial extramedullary hematopoiesis.

Dysosteosclerosis (DOS) is a rare sclerosing bone dysplasia characterized by osteosclerosis and platyspondyly. DOS is genetically heterogeneous and causally associated with mutations in three genes, SLC29A3, CSF1R, and TNFRSF11A. TNFRSF11A has been known as the causal gene for osteopetrosis, autosomal recessive 7, and is recently reported to cause DOS in three cases, which show a complex genotype-phenotype relationship. The phenotypic spectrum of TNFRSF11A-associated sclerosing bone dysplasia remains unclear and needs to be characterized further in more cases with molecular genetic diagnosis. Here, we report another TNFRSF11A-associated DOS case with a homozygous missense mutation (p.R129C). The mutation effect is different from the previous three cases, in which truncated or elongated RANK proteins were generated in isoform specific manner, thus enriching our understanding of the genotype-phenotype association in TNFRSF11A-associated sclerosing bone dysplasia. Besides DOS, our case presented with intracranial extramedullary hematopoiesis, which is an extremely rare condition and has not been identified in any other sclerosing bone dysplasias with molecular genetic diagnosis. Our findings provide the fourth case of TNFRSF11A-associated DOS and further expand its phenotypic spectrum.

Further defining the clinical and molecular spectrum of acromesomelic dysplasia type maroteaux: a Turkish tertiary center experience.

Acromesomelic dysplasia type Maroteaux (AMDM, OMIM #602875) is an autosomal recessive disorder characterized by severe short stature, shortened middle and distal segments of the limbs, redundant skin of fingers, radial head subluxation or dislocation, large great toes and cranium, and normal intelligence. Only the skeletal system appears to be consistently affected. AMDM is caused by biallelic loss-of-function variants in the natriuretic peptide receptor B (NPRB or NPR2, OMIM #108961) which is involved in endochondral ossification and longitudinal growth of limbs and vertebrae. In this study, we investigated 26 AMDM patients from 22 unrelated families and revealed their genetic etiology in 20 families, via Sanger sequencing or exome sequencing. A total of 22 distinct variants in NPR2 (14 missense, 5 nonsense, 2 intronic, and 1 one-amino acid deletion) were detected, among which 15 were novel. They were in homozygous states in 19 patients and in compound heterozygous states in four patients. Parents with heterozygous NPR2 variants were significantly shorter than the control. Extra-skeletal abnormalities, including global developmental delay/intellectual disability, nephrolithiasis, renal cyst, and oligodontia were noted in the patient cohort. The high parental consanguinity rate might have contributed to these findings, probably associated with other gene variants. This study represents the largest cohort of AMDM from Turkey and regional countries and further expands the molecular and clinical spectrum of AMDM.

Whole exome sequencing in unclassified autoinflammatory diseases: more monogenic diseases in the pipeline?

OBJECTIVE: Autoinflammatory diseases (AIDs) are characterized by recurrent sterile systemic inflammation attacks. More than half of the patients remain genetically undiagnosed with next-generation sequencing panels for common AIDs. In this study, we aimed to define phenotype-genotype correlations in a cohort of unclassified AID patients via whole exome sequencing (WES). METHODS: Patients with features of AIDs were included in this study followed in the Department of Pediatric Rheumatology at Hacettepe University. They were first screened for MEFV with Sanger sequencing and then WES performed for the patients with clinically insignificant results. Pre-analysis of WES data was done by considering the 13 most common AID-related genes. Further bioinformatic analysis was performed if the patient remained genetically undiagnosed. RESULTS: The median age at disease onset was 1.2 years (range 0.2-16) and at the time of study recruitment was 14 years (range 3.5-17). In our cohort, WES provided a definite or probable disease-causing variant in 4 of 11 patients (36%). Heterozygous mutations for two of these genes were previously associated with neurological defects (ADAM17, TBK1), also homozygous ADAM17 mutations were observed in one family with neonatal inflammatory skin and bowel disease. Besides, two genes (LIG4, RAG1) were associated with immunodeficiency although the patients had presented with inflammatory features. Finally, for one patient, we associated a strong candidate gene (NLRC3) with autoinflammatory features. CONCLUSION: WES strategy is cost-effective and provides substantial results for a selected group of undefined AID patients. Our results will contribute to the spectrum of unclassified AIDs.

FARS1-related disorders caused by bi-allelic mutations in cytosolic phenylalanyl-tRNA synthetase genes: Look beyond the lungs!

Aminoacyl-tRNA synthetases (ARSs) catalyze the first step of protein biosynthesis (canonical function) and have additional (non-canonical) functions outside of translation. Bi-allelic pathogenic variants in genes encoding ARSs are associated with various recessive mitochondrial and multisystem disorders. We describe here a multisystem clinical phenotype based on bi-allelic mutations in the two genes (FARSA, FARSB) encoding distinct subunits for tetrameric cytosolic phenylalanyl-tRNA synthetase (FARS1). Interstitial lung disease with cholesterol pneumonitis on histology emerged as an early characteristic feature and significantly determined disease burden. Additional clinical characteristics of the patients included neurological findings, liver dysfunction, and connective tissue, muscular and vascular abnormalities. Structural modeling of newly identified missense mutations in the alpha subunit of FARS1, FARSA, showed exclusive mapping to the enzyme's conserved catalytic domain. Patient-derived mutant cells displayed compromised aminoacylation activity in two cases, while remaining unaffected in another. Collectively, these findings expand current knowledge about the human ARS disease spectrum and support a loss of canonical and non-canonical function in FARS1-associated recessive disease.

Spondyloepimetaphyseal dysplasia EXTL3-deficient type: Long-term follow-up and review of the literature.

Spondyloepimetaphyseal dysplasia (SEMD) is a group of genetic skeletal disorders characterized by disproportionate short stature, and varying degrees of vertebral, epiphyseal, and metaphyseal involvement of the skeleton. According to the Nosology and classification of genetic skeletal disorders 2019 revision, more than 20 types of SEMD have been identified, and SEMD with immune deficiency, EXTL3 type is one of the newcomers. Affected individuals display variable skeletal abnormalities and neurodevelopmental findings. Liver and kidney cysts have also been reported frequently. Patients may exhibit varying degrees of immune deficiency as well. To date, only 14 patients from 9 unrelated families with SEMD with immune deficiency, EXTL3 type have been reported in the literature. We report a new patient who is currently 15 years old in whom cystic liver lesions were detected in the prenatal period. Disproportionate short stature, mild developmental delay and a T- NK+ B+ immunological profile were detected in the postnatal follow-up. Exome sequence analysis revealed a previously reported homozygous missense variant in exon 3 c.953C > T; p.(Pro318Leu) in EXTL3.

Biallelic ITGB4 variants in familial pyloric atresia without epidermolysis bullosa: Report of two families with five siblings.

Pyloric atresia (PA) is a rare gastrointestinal anomaly that occurs either as an isolated lesion or in association with other congenital or hereditary anomalies. Familial occurrence of PA with epidermolysis bullosa (EB) has been well documented and variants in ITGA6, ITGB4, and PLEC are known to cause EB with PA. However, no gene variants have been defined in familial isolated PA. Five siblings with familial isolated PA are presented that suggest biallelic ITGB4 variants may underlie the development of PA without EB. Five siblings from two unrelated families with isolated PA were studied with exome sequencing (ES) to identify the genetic etiology in isolated familial cases. Exome sequencing was performed in one affected patient from each family. Validation and segregation studies were done by Sanger sequencing. Parents were first cousins in one family but there was no consanguinity in the other family. Type-2 PA was detected in both families and none of the probands had associated anomalies. All patients underwent successful gastroduodenostomy and have been under follow-up uneventfully. All patients had biallelic ITGB4 variants, c.2032G > T p.(Asp678Tyr) being a novel one. Biallelic ITGB4 variants may underlie the development of PA without associated EB. Further detection of variants in this gene may establish any possible genotype-phenotype correlations.

Further expanding the mutational spectrum of brain abnormalities, neurodegeneration, and dysosteosclerosis: A rare disorder with neurologic regression and skeletal features.

Colony stimulating factor 1 receptor (CSF1R, MIM# 164770) encodes a tyrosine-kinase receptor playing an important role in development of osteoclasts and microglia. Heterozygous CSF1R variants have been known to cause hereditary diffuse leukoencephalopathy with spheroids (HDLS, MIM# 221820), an adult-onset leukoencephalopathy characterized by loss of motor functions and cognitive decline. Recently, a new phenotype characterized by brain abnormalities, neurodegeneration, and dysosteosclerosis (BANDDOS) with biallelic CSF1R pathogenic variants in the etiology has been described. BANDDOS differs from HDLS by early-onset neurodegenerative changes with additional structural brain abnormalities and skeletal findings resembling dysosteosclerosis (DOS). Described skeletal findings of the disease are highly variable ranging from absence of a skeletal phenotype and milder Pyle disease-like to osteopetrosis and DOS. To date, only a few patients carrying biallelic CSF1R variants have been reported. In this clinical report, we describe three siblings with variable skeletal findings along with neurological symptoms ranging from mild to severe in whom exome sequencing revealed a novel homozygous splice site variant in canonical splice donor site of intron 21 adjacent to an exon, which encoding part of kinase domain of CSF1R along with a review of the literature.

Novel insights into diabetes mellitus due to DNAJC3-defect: Evolution of neurological and endocrine phenotype in the pediatric age group.

BACKGROUND: A number of inborn errors of metabolism caused by abnormal protein trafficking that lead to endoplasmic reticulum storage diseases (ERSD) have been defined in the last two decades. One such disorder involves biallelic mutations in the gene encoding endoplasmic reticulum resident co-chaperone DNAJC3 (P58IPK ) that leads to diabetes in the second decade of life, in addition to multiple endocrine dysfunction and nervous system involvement. OBJECTIVE: The aim of this study was to define the natural history of this new form of diabetes, especially the course of abnormalities related to glucose metabolism. METHODS: Whole-exome and Sanger sequencing was used to detect DNAJC3 defect in two patients. Detailed analysis of their clinical history as well as biochemical, neurological and radiological studies were carried out to deduce natural history of neurological and endocrine phenotype. RESULTS: DNAJC3 defect led to beta-cell dysfunction causing hyperinsulinemichypoglycemia around 2 years of age in both patients, which evolved into diabetes with insulin deficiency in the second decade of life, probably due to beta cell loss. Endocrine phenotype involved severe early-onset growth failure due to growth hormone deficiency, and hypothyroidism of central origin. Neurological phenotype involved early onset sensorineural deafness discovered around 5 to 6 years, and neurodegeneration of central and peripheral nervous system in the first two decades of life. CONCLUSION: Biallelic loss-of-function in the ER co-chaperone DNAJC3 leads to a new form of diabetes with early onset hyperinsulinemic hypoglycemia evolving into insulin deficiency as well as severe growth failure, hypothyroidism and diffuse neurodegeneration.

Transcriptome and proteome profiles of human umbilical cord vein CD146+ stem cells.

In this study we used two different techniques in order to isolate pericytes from the wall of human umbilical cord vein and get two different groups of cells were named as "pellet and primer cells". These groups were compared with each other according to their morphologies and stem cell marker expressions. Also, these two different populations were compared with each other and with human bone marrow mesenchymal stem cells (BM-MSCs) according to their transcriptomic profiles. Then, pellet cells proteomic profiles were determined. Our results showed that morphologies and cell surface marker expressions of pellet cells and primer cells are similar. On the other hand, according to immunofluorescence staining results, in contrast to primer cells, pellet cells showed positive NG2 and PDGFR-ß staining. As a result of gene expression profiling, pellet cells have upregulated genes related with muscle, neural and immune cell differentiation, development and pluripotency. On the other hand, primer cells have upregulated adhesion pathway-related genes. In addition to differences between pellet and primer cells, the gene expression profiles of these cell groups are also different from BM-MSCs. The results of transcriptome and proteome analysis of pellet cells were in consistent with each other.

Loss-of-Function Mutations in ELMO2 Cause Intraosseous Vascular Malformation by Impeding RAC1 Signaling.

Vascular malformations are non-neoplastic expansions of blood vessels that arise due to errors during angiogenesis. They are a heterogeneous group of sporadic or inherited vascular disorders characterized by localized lesions of arteriovenous, capillary, or lymphatic origin. Vascular malformations that occur inside bone tissue are rare. Herein, we report loss-of-function mutations in ELMO2 (which translates extracellular signals into cellular movements) that are causative for autosomal-recessive intraosseous vascular malformation (VMOS) in five different families. Individuals with VMOS suffer from life-threatening progressive expansion of the jaw, craniofacial, and other intramembranous bones caused by malformed blood vessels that lack a mature vascular smooth muscle layer. Analysis of primary fibroblasts from an affected individual showed that absence of ELMO2 correlated with a significant downregulation of binding partner DOCK1, resulting in deficient RAC1-dependent cell migration. Unexpectedly, elmo2-knockout zebrafish appeared phenotypically normal, suggesting that there might be human-specific ELMO2 requirements in bone vasculature homeostasis or genetic compensation by related genes. Comparative phylogenetic analysis indicated that elmo2 originated upon the appearance of intramembranous bones and the jaw in ancestral vertebrates, implying that elmo2 might have been involved in the evolution of these novel traits. The present findings highlight the necessity of ELMO2 for maintaining vascular integrity, specifically in intramembranous bones.

A Novel Missense LIG4 Mutation in a Patient With a Phenotype Mimicking Behçet's Disease.

DNA ligase IV (LIG4) syndrome is a rare autosomal recessive disorder, manifesting with variable immune deficiency, growth failure, predisposition to malignancy, and cellular sensitivity to ionizing radiation. The facial features are subtle and variable, as well. Herein, we described an 18-year-old boy, the first child of consanguineous parents who presented with Behçet's disease (BD)-like phenotype, developmental delay, and dysembryoplastic neuroepithelial tumor (DNET). Whole-exome sequencing revealed a homozygous p.Arg871His (c.2612G > A) mutation in LIG4. To date, 35 cases have been reported with LIG4 syndrome. Peripheral blood mononuclear cells of the patient displayed notable sensitivity to ionizing radiation. Flow cytometric annexin V-propidium iodide (PI) and eFluor670 proliferation assays showed accelerated radiation-induced apoptosis and diminished proliferation, respectively. To our knowledge, this is the first case presenting with a BD-like phenotype. This case provides further evidence that rare monogenic defects could be the underlying cause of atypical presentations of some well-described disorders. Moreover, this clinical report further expands the phenotypical spectrum of LIG4 deficiency.