Genetic variants in UNC93B1 predispose to childhood-onset systemic lupus erythematosus.

Rare genetic variants in toll-like receptor 7 (TLR7) are known to cause lupus in humans and mice. UNC93B1 is a transmembrane protein that regulates TLR7 localization into endosomes. In the present study, we identify two new variants in UNC93B1 (T314A, located proximally to the TLR7 transmembrane domain, and V117L) in a cohort of east Asian patients with childhood-onset systemic lupus erythematosus. The V117L variant was associated with increased expression of type I interferons and NF-κB-dependent cytokines in patient plasma and immortalized B cells. THP-1 cells expressing the variant UNC93B1 alleles exhibited exaggerated responses to stimulation of TLR7/-8, but not TLR3 or TLR9, which could be inhibited by targeting the downstream signaling molecules, IRAK1/-4. Heterozygous mice expressing the orthologous Unc93b1V117L variant developed a spontaneous lupus-like disease that was more severe in homozygotes and again hyperresponsive to TLR7 stimulation. Together, this work formally identifies genetic variants in UNC93B1 that can predispose to childhood-onset systemic lupus erythematosus.

[Application of CNVPLUS-array custom microarray in genetic analysis of spinal muscular atrophy].

OBJECTIVE: To assess the application value of CNVPLUS-array for the genetic analysis of Spinal muscular atrophy (SMA). METHODS: From June 2021 to December 2022, CNVPLUS-array technique was employed to test the SMN1 and SMN2 genes among peripheral blood samples from 17 suspected SMA patients, 18 core families with suspected SMA, and 25 healthy individuals. The results were compared with those of multiple ligation-dependent probe amplification (MLPA) assay. Samples with inconsistent results were subjected to nested PCR or comprehensive analysis of SMA. RESULTS: CNVPLUS-array has identified 35 SMA patients, 36 carriers, and 25 healthy individuals. In comparison, MLPA has identified 34 SMA patients, 36 carriers, and 26 healthy individuals. The two methods demonstrated a high consistency (Kappa = 0.968, P < 0.001). Additionally, CNVPLUS-array has identified one patient with compound heterozygous variants of SMN1 and one carrier with a [2+0] genotype. CONCLUSION: CNVPLUS-array not only can accurately determine the copy numbers of SMN1 and SMN2 genes, but also identify point mutations in SMN1 and [2+0] carriers, which has offered a new method for the genetic testing of SMA.

[Analysis of FGD1 gene variant in a child with Aarskog-Scott syndrome].

OBJECTIVE: To detect pathogenic variant of the FGD1 gene in a boy with Aarskog-Scott syndrome. METHODS: Genetic variant was detected by high-throughput sequencing. Suspected variant was verified by Sanger sequencing. The nature and impact of the candidate variant were predicted by bioinformatic analysis. RESULTS: The child was found to harbor a novel c.1906C>T hemizygous variant of the FGD1 gene, which has led to conversion of Arginine to Tryptophane at codon 636(p.Arg636Trp). The same variant was found in his mother but not father. Based on the American College of Medical Genetics and Genomics guidelines, the c.1906C>T variant of FGD1 gene was predicted to be likely pathogenic(PM1+PM2+PM5+PP2+PP3+PP4). CONCLUSION: The novel c.1906C>T variant of the FGD1 gene may underlay the Aarskog-Scott syndrome in this child. Above finding has enabled diagnosis for the boy.

[Prenatal diagnosis of Jacobsen syndrome in a fetus carried by a pregnant woman with intellectual disability].

OBJECTIVE: To assess the value of combined cytogenetic and molecular techniques for the prenatal diagnosis of a pregnant woman with intellectual disability (ID). METHODS: The fetus and its parents were subjected to G-banding karyotyping analysis, single nucleotide polymorphism array (SNP-array) and fluorescence in situ hybridization (FISH) analysis. RESULTS: G-banding karyotype analysis revealed that the woman has carried a chromosomal microdeletion 46,XX,del(11)(q24), and the fetus was a carrier of 46,XN,del(11)(q24)mat. Subsequent SNP-array and FISH analysis of the pregnant woman indicated that the microdeletion has mapped to 11q24.1-q25. Both the pregnant woman and her fetus were diagnosed with Jacobsen syndrome. CONCLUSION: Combined use of cytogenetic and molecular genetic techniques can facilitate diagnosis of patients with intellectual disability.

Retrospective analysis of 4761 cases who underwent amniocentesis in southeast China.

The aim of this study was to examine the clinical and cytogenetic results of 4761 amniocentesis (AS) cases retrospectively in our clinic in southeast China. The prenatal diagnosis indications, detected chromosomal anomalies and the detection rate of chromosomal abnormalities were studied in 4761 patients who underwent AS between June 2014 and July 2016 retrospectively. Chromosomal abnormality was detected in 137 (2.88%) of the 4761 samples (89.1% numerical, 10.9% structural). The most frequent numerical chromosomal abnormality was trisomy 21 (59.0%). Clinically insignificant polymorphisms were the most frequent structural changes (n = 284). In our study, the frequency and proportion of abnormal karyotypes varied substantially across different maternal AS indications. Impact statement What is already known on this subject: Several studies on amniocentesis indications and results have been reported from China and from other countries. It has been known that the most common indications were the increased risk at maternal serum screenings (MSS) and advanced maternal age (AMA). What the results of this study add: In our study we make a conclusion that the indications and results of AS cases from our centre indicated the significance of genetic screening. What the implications are of these findings for clinical practice and/or further research: Our data could offer informative data for proper prenatal genetic counselling of pregnant women and their partners in Wuxi, China.

[Prenatal diagnosis for a women with a suspected birth history of Angelman syndrome].

OBJECTIVE: To verify the diagnosis of Angelman syndrome(AS) in a proband in order to provide prenatal diagnosis for his family. METHODS: Array comparative genome hybridization(array-CGH) and fluorescence in situ hybridization(FISH) on metaphase chromosomes were performed. RESULTS: The karyotype of the proband was normal, and a regional deletion of 15q11.1-11.2 was detected by array-CGH. FISH analysis has confirmed loss of heterozygosity in 15q11.2. No positive results were obtained by array-CGH or karyotype analysis. Amniotic fluid sample was taken from the proband's mother upon her subsequent pregnancy. The karyotype of the fetus was normal, but SNP microarray chip analysis has identified loss of heterozygosity in 8p23.1-p22. As no abnormality was observed by ultrasound and other prenatal examinations, the pregnancy was recommended to continue to full-term, and a healthy infant was born. CONCLUSION: Clinically suspected AS can be diagnosed by array-CGH and FISH. The result may facilitate accurate genetic counseling and prenatal diagnosis for the affected family.

[Prenatal diagnosis of a fetus with partial trisomy 8p resulting from a balanced maternal translocation by array-based comparative genomic hybridization].

OBJECTIVE: To determine the karyotype of a fetus with transverse aortic arch hypoplasia, and to investigate the feasibility of array-based comparative genomic hybridization (array-CGH) for molecular genetic diagnosis. METHODS: G-banding was performed to analyze the karyotypes of the fetus and its parents, and array-CGH was applied to identify the chromosomal abnormality of the fetus. RESULTS: G-banding analysis revealed that the pregnant woman has carried a balanced translocation 46,XX, t(8;16)(p21;q24), while the fetus has carried an unbalanced translocation 46,XX,der(16)t(8;16)(p21;q24)mat. Array-CGH analysis suggested that the derivative chromosomal fragment has originated from 8p with breakpoints in 8p23.3-p21.3. CONCLUSION: Trisomy 8p23.3-p21.3 may have predisposed to transverse aortic arch hypoplasia in the fetus. Parental karyotype analysis could help to characterize the translocation and evaluate the recurrent risk. Compared with routine karyotype analysis, aCGH has a higher resolution and greater accuracy for mapping chromosomal aberrations.

Pathogenic fungus Microsporum canis activates the NLRP3 inflammasome.

Microsporum canis is a pathogenic fungus with worldwide distribution that causes tinea capitis in animals and humans. M. canis also causes invasive infection in immunocompromised patients. To defy pathogenic fungal infection, the host innate immune system is the first line of defense. As an important arm of innate immunity, the inflammasomes are intracellular multiprotein complexes that control the activation of caspase-1, which cleaves proinflammatory cytokine pro-interleukin-1ß (IL-1ß) into its mature form. To determine whether the inflammasome is involved in the host defense against M. canis infection, we challenged human monocytic THP-1 cells and mouse dendritic cells with a clinical strain of M. canis isolated from patients with tinea capitis. We found that M. canis infection triggered rapid secretion of IL-1ß from both THP-1 cells and mouse dendritic cells. Moreover, by using gene-specific shRNA and competitive inhibitors, we determined that M. canis-induced IL-1ß secretion was dependent on NLRP3. The pathways proposed for NLRP3 inflammasome activation, namely, cathepsin B activity, K(+) efflux, and reactive oxygen species production, were all required for the inflammasome activation triggered by M. canis. Meanwhile, Syk, Dectin-1, and Card9 were found to be involved in M. canis-induced IL-1ß secretion via regulation of pro-IL-1ß transcription. More importantly, our data revealed that M. canis-induced production of IL-1ß was dependent on the NLRP3 inflammasome in vivo. Together, this study unveils that the NLRP3 inflammasome exerts a critical role in host innate immune responses against M. canis infection, and our data suggest that diseases that result from M. canis infection might be controlled by regulating the activation of inflammasomes.

Heterozygous de novo dominant negative mutation of REXO2 results in interferonopathy.

Mitochondrial RNA (mtRNA) in the cytosol can trigger the innate immune sensor MDA5, and autoinflammatory disease due to type I IFN. Here, we show that a dominant negative mutation in the gene encoding the mitochondrial exonuclease REXO2 may cause interferonopathy by triggering the MDA5 pathway. A patient characterized by this heterozygous de novo mutation (p.T132A) presented with persistent skin rash featuring hyperkeratosis, parakeratosis and acanthosis, with infiltration of lymphocytes and eosinophils around small blood vessels. In addition, circulating IgE levels and inflammatory cytokines, including IFNα, are found consistently elevated. Transcriptional analysis highlights a type I IFN gene signature in PBMC. Mechanistically, REXO2 (T132A) lacks the ability to cleave RNA and inhibits the activity of wild-type REXO2. This leads to an accumulation of mitochondrial dsRNA in the cytosol, which is recognized by MDA5, leading to the associated type I IFN gene signature. These results demonstrate that in the absence of appropriate regulation by REXO2, aberrant cellular nucleic acids may accumulate and continuously trigger innate sensors, resulting in an inborn error of immunity.

MCM8-mediated mitophagy protects vascular health in response to nitric oxide signaling in a mouse model of Kawasaki disease.

Mitophagy is a major quality control pathway that removes unwanted or dysfunctional mitochondria and plays an essential role in vascular health. Here we show that MCM8 expression is significantly decreased in children with Kawasaki disease (KD) who developed coronary artery aneurysms. Mechanistically, we discovered that nitric oxide signaling promotes TRIM21-mediated MCM8 ubiquitination, which disrupts its interaction with MCM9 and promotes its cytosolic export. In the cytosol, MCM8 relocates to the mitochondria pore-forming proteins and promotes their ubiquitination by TRIM21. In addition, MCM8 directly recruits LC3 via its LC3-interacting region (LIR) motif and initiates mitophagy. This suppresses mitochondrial DNA-mediated activation of type I interferon via cGAS and STING. Mice that are deficient in Mcm8, Trim21 and Nos2 or reconstituted with the East-Asian-specific MCM8-P276 variant develop more severe coronary artery vasculopathy in the Lactobacillus casei extract-induced KD model. Collectively, the data suggest that MCM8 protects vascular health in the KD setting.

Acapsular Cryptococcus neoformans activates the NLRP3 inflammasome.

Cryptococcus neoformans (C. neoformans) is an opportunistic fungal pathogen that mainly infects immunocompromised individuals such as AIDS patients. Although cell surface receptors for recognition of C. neoformans have been studies intensively, cytoplasmic recognition of this pathogen remains unclear. As an important detector of pathogen infection, inflammasome can sense and get activated by infection of various pathogens, including pathogenic fungi such as Candida albicans and Aspergillus fumigatus. Our present study showed that acapsular C. neoformans (cap59Δ) activated the NLRP3-, but not AIM2-nor NLRC4- inflammasome. During this process, viability of the fungus was required. Moreover, our in vivo results showed that during the pulmonary infection of cap59Δ, immune cell infiltration into the lung and effective clearance of the fungus were both dependent on the presence of NLRP3 inflammasome. In summary, our data suggest that the capsule of C. neoformans prevents recognition of the fungus by host NLRP3 inflammasome and indicate that manipulation of inflammasome activity maybe a novel approach to control C. neoformans infection.

Biocompatibility of magnetic Fe3O4 nanoparticles and their cytotoxic effect on MCF-7 cells.

BACKGROUND: The objective of this study was to evaluate the synthesis and biocompatibility of Fe3O4 nanoparticles and investigate their therapeutic effects when combined with magnetic fluid hyperthermia on cultured MCF-7 cancer cells. METHODS: Magnetic Fe3O4 nanoparticles were prepared using a coprecipitation method. The appearance, structure, phase composition, functional groups, surface charge, magnetic susceptibility, and release in vitro were characterized by transmission electron microscopy, x-ray diffraction, scanning electron microscopy-energy dispersive x-ray spectroscopy, and a vibrating sample magnetometer. Blood toxicity, in vitro toxicity, and genotoxicity were investigated. Therapeutic effects were evaluated by MTT [3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide] and flow cytometry assays. RESULTS: Transmission electron microscopy revealed that the shapes of the Fe3O4 nanoparticles were approximately spherical, with diameters of about 26.1 ± 5.2 nm. Only the spinel phase was indicated in a comparison of the x-ray diffraction data with Joint Corporation of Powder Diffraction Standards (JCPDS) X-ray powder diffraction files. The O-to-Fe ratio of the Fe3O4was determined by scanning electron microscopy-energy dispersive x-ray spectroscopy elemental analysis, and approximated pure Fe3O4. The vibrating sample magnetometer hysteresis loop suggested that the Fe3O4nanoparticles were superparamagnetic at room temperature. MTT experiments showed that the toxicity of the material in mouse fibroblast (L-929) cell lines was between Grade 0 to Grade 1, and that the material lacked hemolysis activity. The acute toxicity (LD(50)) was 8.39 g/kg. Micronucleus testing showed no genotoxic effects. Pathomorphology and blood biochemistry testing demonstrated that the Fe3O4 nanoparticles had no effect on the main organs and blood biochemistry in a rabbit model. MTT and flow cytometry assays revealed that Fe3O4 nano magnetofluid thermotherapy inhibited MCF-7 cell proliferation, and its inhibitory effect was dose-dependent according to the Fe3O4 nano magnetofluid concentration. CONCLUSION: The Fe3O4 nanoparticles prepared in this study have good biocompatibility and are suitable for further application in tumor hyperthermia.

Preparation and biodistribution of 188Re-labeled folate conjugated human serum albumin magnetic cisplatin nanoparticles (188Re-folate-CDDP/HSA MNPs) in vivo.

BACKGROUND: The purpose of this study was to develop intraperitoneal hyperthermic therapy based on magnetic fluid hyperthermia, nanoparticle-wrapped cisplatin chemotherapy, and magnetic particles of albumin. In addition, to combine the multiple-killing effects of hyperthermal targeting therapy, chemotherapy, and radiotherapy, the albumin-nanoparticle surfaces were linked with radionuclide (188)Re-labeled folic acid ligand ((188)Re-folate-CDDP/HSA). METHODS: Human serum albumin was labeled with (188)Re using the pre-tin method. Reaction time and optimal conditions of labeling were investigated. The particles were intravenously injected into mice, which were sacrificed at different time points. Radioactivity per gram of tissue of percent injected dose (% ID/g) was measured in vital organs. The biodistribution of (188)Re-folate-CDDP/HAS magnetic nanoparticles was assessed. RESULTS: Optimal conditions for (188)Re-labeled folate-conjugated albumin combined with cisplatin magnetic nanoparticles were: 0.1 mL of sodium gluconate solution (0.3 mol/L), 0.1 mL of concentrated hydrochloric acid with dissolved stannous chloride (10 mg/mL), 0.04 mL of acetic acid buffer solution (pH 5, 0.2 mol/L), 30 mg of folate-conjugated albumin combined with cisplatin magnetic nanoparticles, and (188)ReO(4) eluent (0.1 mL). The rate of (188)Re-folate-CDDP-HSA magnetic nanoparticle formation exceeded 90%, and radiochemical purity exceeded 95%. The overall labeling rate was 83% in calf serum at 37°C. The major uptake tissues were the liver, kidney, intestine, and tumor after the (188)Re-folate-CDDP/HSA magnetic nanoparticles were injected into nude mice. Uptake of (188)Re-folate-CDDP/HSA magnetic nanoparticles increased gradually after injection, peaked at 8 hours with a value of 8.83 ± 1.71, and slowly decreased over 24 hours in vivo. CONCLUSION: These results indicate that (188)Re-folate-CDDP/HSA magnetic nanoparticles can be used in radionuclide-targeted cancer therapy. Surface-modified albumin nanoparticles with folic acid ligand-labeled radionuclide ((188)Re) were successfully prepared, laying the foundation for a triple-killing effect of thermotherapy, chemotherapy, and radiation therapy.