A Functional Polymorphism Downstream of Vitamin A Regulator Gene CYP26B1 Is Associated with Hand Osteoarthritis.

While genetic analyses have revealed ~100 risk loci associated with osteoarthritis (OA), only eight have been linked to hand OA. Besides, these studies were performed in predominantly European and Caucasian ancestries. Here, we conducted a genome-wide association study in the Han Chinese population to identify genetic variations associated with the disease. We recruited a total of 1136 individuals (n = 420 hand OA-affected; n = 716 unaffected control subjects) of Han Chinese ancestry. We carried out genotyping using Axiom Asia Precisi on Medicine Research Array, and we employed the RegulomeDB database and RoadMap DNase I Hypersensitivity Sites annotations to further narrow down our potential candidate variants. Genetic variants identified were tested in the Geisinger's hand OA cohort selected from the Geisinger MyCode community health initiative (MyCode®). We also performed a luciferase reporter assay to confirm the potential impact of top candidate single-nucleotide polymorphisms (SNPs) on hand OA. We identified six associated SNPs (p-value = 6.76 × 10-7-7.31 × 10-6) clustered at 2p13.2 downstream of the CYP26B1 gene. The strongest association signal identified was rs883313 (p-value = 6.76 × 10-7, odds ratio (OR) = 1.76), followed by rs12713768 (p-value = 1.36 × 10-6, OR = 1.74), near or within the enhancer region closest to the CYP26B1 gene. Our findings showed that the major risk-conferring CC haplotype of SNPs rs12713768 and rs10208040 [strong linkage disequilibrium (LD); D' = 1, r2 = 0.651] drives 18.9% of enhancer expression activity. Our findings highlight that the SNP rs12713768 is associated with susceptibility to and severity of hand OA in the Han Chinese population and that the suggested retinoic acid signaling pathway may play an important role in its pathogenesis.

Palmitoyl Acyltransferase Activity of ZDHHC13 Regulates Skin Barrier Development Partly by Controlling PADi3 and TGM1 Protein Stability.

Deficiency of the palmitoyl-acyl transferase ZDHHC13 compromises skin barrier permeability and renders mice susceptible to environmental bacterial infection and inflammatory dermatitis. It had been unclear how the lack of ZDHHC13 proteins resulted in cutaneous abnormalities. In this study, we first demonstrate that enzymatic palmitoylation activity, rather than protein scaffolding, by ZDHHC13 is essential for skin barrier integrity, showing that knock-in mice bearing an enzymatically dead DQ-to-AA ZDHHC13 mutation lost their hair after weaning cyclically, recapitulating knockout phenotypes of skin inflammation and dermatitis. To establish the ZDHHC13 substrates responsible for skin barrier development, we employed quantitative proteomic approaches to identify protein molecules whose palmitoylation is tightly controlled by ZDHHC13. We identified over 300 candidate proteins that could be classified into four biological categories: immunological disease, skin development and function, dermatological disease, and lipid metabolism. Palmitoylation of three of these candidates-loricrin, peptidyl arginine deiminase type III, and keratin fiber crosslinker transglutaminase 1-by ZDHHC13 was confirmed by biochemical assay. Palmitoylation was critical for in vivo protein stability of the latter two candidates. Our findings reveal the importance of protein palmitoylation in skin barrier development, partly by promoting envelope protein crosslinking and the filaggrin processing pathway.

Factors Associated With Remote Diffusion-Weighted Imaging Lesions in Spontaneous Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: Remote diffusion-weighted imaging lesions (R-DWILs) have been detected in patients with spontaneous intracerebral hemorrhage (ICH) and may be correlated with clinical outcome. However, the mechanisms and characteristics of R-DWILs have not been fully elucidated. In this study, we sought to demonstrate the clinical characteristics of R-DWILs in spontaneous ICH. METHODS: We prospectively collected data with spontaneous ICH patients from November 2016 to December 2017. In these patients, cerebral magnetic resonance imaging was performed within 28 days after ICH onset. R-DWIL was defined as a hyperintensity signal in diffusion-weighted imaging with corresponding hypointensity in apparent diffusion coefficient, and at least 20 mm apart from the hematoma. We compared two groups of patients with or without R-DWIL with the demographic and clinical characteristics, laboratory parameters, and imaging characteristics, by using univariate and multivariate analysis. RESULTS: Of the 222 patients enrolled, a total of 75 R-DWILs were observed in 41 patients (18.5%). Among these lesions, the cortical and subcortical areas were the predominant locations with a proportion of 77.3%. The median diameter of R-DWILs was 7 mm (range 2-20 mm). Twelve patients were found having more than one lesion, with five among which showed R-DWILs in multiple cerebral arterial territories. In multivariate modeling, higher fasting glucose (OR 1.231; 95% CI 1.035-1.465; p = 0.019) and more severe white matter hyperintensity (WMH) (OR 6.589; 95% CI 2.975-14.592; p < 0.001) were independent factors related to the presence of R-DWILs. CONCLUSION: In our study, approximately one-fifth of ICH patients showed coexistence of R-DWIL. Higher fasting glucose and more severe WMH were associated with R-DWIL occurrence in spontaneous ICH.

Role of S-Palmitoylation by ZDHHC13 in Mitochondrial function and Metabolism in Liver.

Palmitoyltransferase (PAT) catalyses protein S-palmitoylation which adds 16-carbon palmitate to specific cysteines and contributes to various biological functions. We previously reported that in mice, deficiency of Zdhhc13, a member of the PAT family, causes severe phenotypes including amyloidosis, alopecia, and osteoporosis. Here, we show that Zdhhc13 deficiency results in abnormal liver function, lipid abnormalities, and hypermetabolism. To elucidate the molecular mechanisms underlying these disease phenotypes, we applied a site-specific quantitative approach integrating an alkylating resin-assisted capture and mass spectrometry-based label-free strategy for studying the liver S-palmitoylome. We identified 2,190 S-palmitoylated peptides corresponding to 883 S-palmitoylated proteins. After normalization using the membrane proteome with TMT10-plex labelling, 400 (31%) of S-palmitoylation sites on 254 proteins were down-regulated in Zdhhc13-deficient mice, representing potential ZDHHC13 substrates. Among these, lipid metabolism and mitochondrial dysfunction proteins were overrepresented. MCAT and CTNND1 were confirmed to be specific ZDHHC13 substrates. Furthermore, we found impaired mitochondrial function in hepatocytes of Zdhhc13-deficient mice and Zdhhc13-knockdown Hep1-6 cells. These results indicate that ZDHHC13 is an important regulator of mitochondrial activity. Collectively, our study allows for a systematic view of S-palmitoylation for identification of ZDHHC13 substrates and demonstrates the role of ZDHHC13 in mitochondrial function and metabolism in liver.

[The Analysis of Microcavity-Integrated Graphene Photodetector's SNR Based on 1.06 µm].

Avalanche photodiode is widely used in laser rangefinder due to high gain characteristics, but introduces highly additive noise during the time of current's multiplication that makes laser rangefinder's SNR meet bottleneck. This paper proposes a method of designing a high SNR's graphene photodetector based on microcavity. The graphene's unique optoelectronic properties make it an ideal platform for a variety of photonic applications, such as fast lasers, optical modulators, transparent electrodes, and ultrafast photodetectors. It has been recognized internationally to have dominant advantages in photodetectors due to its high carrier mobility, gapless spectrum, and frequency-independent absorption coefficient. With the wavelength of 1.06 µm, the mechanism of light waves' transmission in the cavity and the graphehne's absorption are studied by using optical transmission matrix method and scattering matrix method; the light absorption model of the graphene photodetector based on microcavity is established. Device's final quantum efficiency reaches 91.2%, respectively reaches 0.778 A·W(-1), its full width at half maximum (FWHM) reaches 6 nm; the influence between graphene's position in the microcavity and device's absorption shows that device's absorption's peak value changes periodically with graphene's position under resonant condition, and the variety of length of microcavity does not have any influence on the peak value, but changes the graphene's position when absorption reaches peak value, on the condition that the length of microcavity is n times of half of wavelength, the number of device's absorption peak value is 2n with the variety of graphene's position, and all the peak values are symmetrical with respect to the center of microcavity, the final graphene's position is 0.402 8 mm away from the top mirror of microcavity, and the absorption reaches 94%, Compared with single layer graphene, the absorption rate increases 16 dB; By solving SNR equation of the graphene photodetector based on microcavity and SNR equation of the avalanche photodiode, eventually finds that the SNR of the graphene photodetector based on microcavity is 90.3, which raises 10 dB compared with the avalanche photodiode's. Theoretical analysis shows the graphene photodetector based on microcavity has high absorption rate, high quantum efficiency, and high SNR. In this paper, the research achievements provide a theoretical reference to update and design higher SNR photodetector used in laser rangefinder's receiving system.

Protein Palmitoylation by ZDHHC13 Protects Skin against Microbial-Driven Dermatitis.

Atopic dermatitis is a complex chronic inflammatory skin disorder that results from intimate interactions among genetic predisposition, host environment, skin barrier defects, and immunological factors. However, a clear genetic roadmap leading to atopic dermatitis remains to be fully explored. From a genome-wide mutagenesis screen, deficiency of ZDHHC13, a palmitoylacyl transferase, has previously been associated with skin and multitissue inflammatory phenotypes. Here, we report that ZDHHC13 is required for skin barrier integrity and that deficiency of ZDHHC13 renders mice susceptible to environmental bacteria, resulting in persistent skin inflammation and an atopic dermatitis-like disease. This phenotype is ameliorated in a germ-free environment and is also attenuated by antibiotic treatment, but not by deletion of the Rag1 gene, suggesting that a microbial factor triggers inflammation rather than intrinsic adaptive immunity. Furthermore, skin from ZDHHC13-deficient mice has both elevated levels of IL-33 and type 2 innate lymphoid cells, reinforcing the role of innate immunity in the development of atopic dermatitis. In summary, our study suggests that loss of ZDHHC13 in skin impairs the integrity of multiple barrier functions and leads to a dermatitis lesion in response to microbial encounters.

Cyclic Alopecia and Abnormal Epidermal Cornification in Zdhhc13-Deficient Mice Reveal the Importance of Palmitoylation in Hair and Skin Differentiation.

Many biochemical pathways involved in hair and skin development have not been investigated. Here, we reported on the lesions and investigated the mechanism underlying hair and skin abnormalities in Zdhhc13(skc4) mice with a deficiency in DHHC13, a palmitoyl-acyl transferase encoded by Zdhhc13. Homozygous affected mice showed ragged and dilapidated cuticle of the hair shaft (CUH, a hair anchoring structure), poor hair anchoring ability, and premature hair loss at early telogen phase of the hair cycle, resulting in cyclic alopecia. Furthermore, the homozygous affected mice exhibited hyperproliferation of the epidermis, disturbed cornification, fragile cornified envelope (CE, a skin barrier structure), and impaired skin barrier function. Biochemical investigations revealed that cornifelin, which contains five palmitoylation sites at cysteine residues (C58, C59, C60, C95, and C101), was a specific substrate of DHHC13 and that it was absent in the CUH and CE structures of the affected mice. Furthermore, cornifelin levels were markedly reduced when two palmitoylated cysteines were replaced with serine (C95S and C101S). Taken together, our results suggest that DHHC13 is important for hair anchoring and skin barrier function and that cornifelin deficiency contributes to cyclic alopecia and skin abnormalities in Zdhhc13(skc4) mice.

Palmitoyl acyltransferase, Zdhhc13, facilitates bone mass acquisition by regulating postnatal epiphyseal development and endochondral ossification: a mouse model.

ZDHHC13 is a member of DHHC-containing palmitoyl acyltransferases (PATs) family of enzymes. It functions by post-translationally adding 16-carbon palmitate to proteins through a thioester linkage. We have previously shown that mice carrying a recessive Zdhhc13 nonsense mutation causing a Zdhcc13 deficiency develop alopecia, amyloidosis and osteoporosis. Our goal was to investigate the pathogenic mechanism of osteoporosis in the context of this mutation in mice. Body size, skeletal structure and trabecular bone were similar in Zdhhc13 WT and mutant mice at birth. Growth retardation and delayed secondary ossification center formation were first observed at day 10 and at 4 weeks of age, disorganization in growth plate structure and osteoporosis became evident in mutant mice. Serial microCT from 4-20 week-olds revealed that Zdhhc13 mutant mice had reduced bone mineral density. Through co-immunoprecipitation and acyl-biotin exchange, MT1-MMP was identified as a direct substrate of ZDHHC13. In cells, reduction of MT1-MMP palmitoylation affected its subcellular distribution and was associated with decreased VEGF and osteocalcin expression in chondrocytes and osteoblasts. In Zdhhc13 mutant mice epiphysis where MT1-MMP was under palmitoylated, VEGF in hypertrophic chondrocytes and osteocalcin at the cartilage-bone interface were reduced based on immunohistochemical analyses. Our results suggest that Zdhhc13 is a novel regulator of postnatal skeletal development and bone mass acquisition. To our knowledge, these are the first data to suggest that ZDHHC13-mediated MT1-MMP palmitoylation is a key modulator of bone homeostasis. These data may provide novel insights into the role of palmitoylation in the pathogenesis of human osteoporosis.

Mouse model of glycogen storage disease type III.

Glycogen storage disease type IIIa (GSD IIIa) is caused by a deficiency of the glycogen debranching enzyme (GDE), which is encoded by the Agl gene. GDE deficiency leads to the pathogenic accumulation of phosphorylase limit dextrin (PLD), an abnormal glycogen, in the liver, heart, and skeletal muscle. To further investigate the pathological mechanisms behind this disease and develop novel therapies to treat this disease, we generated a GDE-deficient mouse model by removing exons after exon 5 in the Agl gene. GDE reduction was confirmed by western blot and enzymatic activity assay. Histology revealed massive glycogen accumulation in the liver, muscle, and heart of the homozygous affected mice. Interestingly, we did not find any differences in the general appearance, growth rate, and life span between the wild-type, heterozygous, and homozygous affected mice with ad libitum feeding, except reduced motor activity after 50 weeks of age, and muscle weakness in both the forelimb and hind legs of homozygous affected mice by using the grip strength test at 62 weeks of age. However, repeated fasting resulted in decreased survival of the knockout mice. Hepatomegaly and progressive liver fibrosis were also found in the homozygous affected mice. Blood chemistry revealed that alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) activities were significantly higher in the homozygous affected mice than in both wild-type and heterozygous mice and the activity of these enzymes further increased with fasting. Creatine phosphokinase (CPK) activity was normal in young and adult homozygous affected mice. However, the activity was significantly elevated after fasting. Hypoglycemia appeared only at a young age (3 weeks) and hyperlipidemia was not observed in our model. In conclusion, with the exception of normal lipidemia, these mice recapitulate human GSD IIIa; moreover, we found that repeated fasting was detrimental to these mice. This mouse model will be useful for future investigation regarding the pathophysiology and treatment strategy of human GSD III.

Mice with alopecia, osteoporosis, and systemic amyloidosis due to mutation in Zdhhc13, a gene coding for palmitoyl acyltransferase.

Protein palmitoylation has emerged as an important mechanism for regulating protein trafficking, stability, and protein-protein interactions; however, its relevance to disease processes is not clear. Using a genome-wide, phenotype driven N-ethyl-N-nitrosourea-mediated mutagenesis screen, we identified mice with failure to thrive, shortened life span, skin and hair abnormalities including alopecia, severe osteoporosis, and systemic amyloidosis (both AA and AL amyloids depositions). Whole-genome homozygosity mapping with 295 SNP markers and fine mapping with an additional 50 SNPs localized the disease gene to chromosome 7 between 53.9 and 56.3 Mb. A nonsense mutation (c.1273A>T) was located in exon 12 of the Zdhhc13 gene (Zinc finger, DHHC domain containing 13), a gene coding for palmitoyl transferase. The mutation predicted a truncated protein (R425X), and real-time PCR showed markedly reduced Zdhhc13 mRNA. A second gene trap allele of Zdhhc13 has the same phenotypes, suggesting that this is a loss of function allele. This is the first report that palmitoyl transferase deficiency causes a severe phenotype, and it establishes a direct link between protein palmitoylation and regulation of diverse physiologic functions where its absence can result in profound disease pathology. This mouse model can be used to investigate mechanisms where improper palmitoylation leads to disease processes and to understand molecular mechanisms underlying human alopecia, osteoporosis, and amyloidosis and many other neurodegenerative diseases caused by protein misfolding and amyloidosis.

Long-term follow-up of Taiwanese Chinese patients treated early for 6-pyruvoyl-tetrahydropterin synthase deficiency.

OBJECTIVE: To report the long-term results of early initiation of treatment of 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency. DESIGN: Between 1988 and 2000, 12 newborns with PTPS deficiency who underwent early treatment at our hospital were identified. All patients received tetrahydrobiopterin replacement in a daily dosage between approximately 2 and 4 mg/kg. The dosages of levodopa replacement were 10 to 15 mg/kg/d, which is considerably higher than the typically recommended dosages of less than 7 mg/kg/d for patients aged younger than 2 years and 8 to 10 mg/kg/d for patients aged 2 years or older. Replacement with 5-hydroxytryptophan varied widely among patients. SETTING: Taipei Veterans General Hospital. Patients Twelve newborns. INTERVENTIONS: Treatment with tetrahydrobiopterin, levodopa, and 5-hydroxytryptophan. Main Outcome Measure IQ score. RESULTS: The mean (SD) IQ score of our PTPS-deficient patients was 96.7 (9.7; range 86-119), which is considerably higher than previous reports of other populations of PTPS-deficient patients. All patients reached a normal IQ on high daily dosages of levodopa replacement, without developing apparent long-term levodopa-induced adverse effects. We also observed a correlation between long-term IQ score and genotype, birth weight, and age at initiation of treatment. CONCLUSIONS: An effective newborn screening referral program and early initiation of appropriate therapy preserved the IQ scores of PTPS-deficient patients.

Paternal gonadal mosaicism of NIPBL mutation in a father of siblings with Cornelia de Lange syndrome.

OBJECTIVES: We report two siblings, a boy and a girl, with Cornelia de Lange syndrome (CdLS), born to unaffected parents, and attempt to delineate the underlying molecular mechanism leading to familial recurrence. METHODS: Nipped-B-like (NIPBL) gene mutations were screened using in denaturing high-performance liquid chromatography and sequencing in peripheral blood samples, from one of the affected siblings and her parents, as well as from a sperm sample from the father. RESULTS: A heterozygous missense NIPBL mutation, D2433G, was identified in the peripheral blood sample of the affected girl, but not in the peripheral blood samples of her parents. The D2433G mutation was also found in the sperm sample of the father. CONCLUSION: Gonadal mosaicism represents an underappreciated feature of the inheritance pattern of CdLS. To our knowledge, the girl represents the first CdLS patient whose father was documented to have a population of mutant sperm. When a sperm analysis indicates the presence of a mutant allele, it may be reasonable to offer prenatal genetic testing to the family in subsequent pregnancies, given that the sensitivity of fetal ultrasonography is relatively low.