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SLC29A3 spectrum disorder, also known as histiocytosis-lymphadenopathy plus syndrome (HLPS), presents a wide variety of multi-systemic manifestations that can be mistaken for other conditions. Herein, we report a 9-year-old girl who presented with a complex clinical presentation since birth, including chronic generalized lymphadenopathy in association with hepatosplenomegaly, short stature, flexion contractures, hearing loss, hyperpigmentation, and heart anomalies. She was ultimately diagnosed with the SLC29A3 spectrum disorder., (© 2024 Wiley Periodicals LLC.)

A 19-year-old girl presented with symmetric and bilateral hyperpigmentation, an indurated lesion that initially appeared on the axillary fold at the age of 14, which then extended to the lower back, anterior aspect of both thighs, and popliteal fold. No hypertrichosis was observed (Figure 1).The patient was the youngest of the four children, born from the first-degree consanguineous marriage. She was born at full term and weighed 2,420 g at birth. No similar patient was present in the family. The patient experienced delayed motor acquisition and stature growth (3rd percentile) until the age of 4. Right hypoacusis was diagnosed at the age of 6. She developed hallux valgus, flexion contracture of the fin-gers and toes, barrel deformity of the anterior thorax, and recurrent fever. The laboratory tests, including fasting blood glucose, -triglycerides, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were normal. Her abdominal, pelvic, and transthoracic ultrasound scans were normal, with no hepatosplenomegaly, lymphadenopathy, or cardiac abnormalities. Histologic analysis demonstrated patchy acanthosis of the epidermis, with orthokeratotic hyperkeratosis. Keratinocyte hyperpigmentation and spongiosis at certain areas were observed with moder-ate inflammation because of the infiltration of lymphocytes, histiocytes, and plasma cells. Immunohistochemical analysis showed macrosialin (CD68+) and common gamma chain (γ c ) CD132. Germline mutations in the SLC29A3 gene were not analyzed. The patient was prescribed dermocorticoids with depigmentation therapy, which demonstrated moderate clinical evolution.

Huntington's disease (HD) is a hereditary neurodegenerative disorder characterized by involuntary movements, cognitive deficits, and psychiatric symptoms. Currently, there is no cure, and only limited treatments are available to manage the symptoms and to slow down the disease's progression. The molecular and cellular mechanisms of HD's pathogenesis are complex, involving immune cell activation, altered protein turnover, and disturbance in brain energy homeostasis. Microglia have been known to play a dual role in HD, contributing to neurodegeneration through inflammation but also enacting neuroprotective effects by clearing mHTT aggregates. However, little is known about the contribution of microglial metabolism to HD progression. This study explores the impact of a microglial metabolite transporter, equilibrative nucleoside transporter 3 (ENT3), in HD. Known as a lysosomal membrane transporter protein, ENT3 is highly enriched in microglia, with its expression correlated with HD severity. Using the R6/2 ENT3 -/- mouse model, we found that the deletion of ENT3 increases microglia numbers yet worsens HD progression, leading to mHTT accumulation, cell death, and disturbed energy metabolism. These results suggest that the delicate balance between microglial metabolism and function is crucial for maintaining brain homeostasis and that ENT3 has a protective role in ameliorating neurodegenerative processes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: The SLC29A3 gene, which encodes a nucleoside transporter protein, is primarily located in intracellular membranes. The mutations in this gene can give rise to various clinical manifestations, including H syndrome, dysosteosclerosis, Faisalabad histiocytosis, and pigmented hypertrichosis with insulin-dependent diabetes. The aim of this study is to present two Iranian patients with H syndrome and to describe a novel start-loss mutation in SLC29A3 gene., Methods: In this study, we employed whole-exome sequencing (WES) as a method to identify genetic variations that contribute to the development of H syndrome in a 16-year-old girl and her 8-year-old brother. These siblings were part of an Iranian family with consanguineous parents. To confirmed the pathogenicity of the identified variant, we utilized in-silico tools and cross-referenced various databases to confirm its novelty. Additionally, we conducted a co-segregation study and verified the presence of the variant in the parents of the affected patients through Sanger sequencing., Results: In our study, we identified a novel start-loss mutation (c.2T > A, p.Met1Lys) in the SLC29A3 gene, which was found in both of two patients. Co-segregation analysis using Sanger sequencing confirmed that this variant was inherited from the parents. To evaluate the potential pathogenicity and novelty of this mutation, we consulted various databases. Additionally, we employed bioinformatics tools to predict the three-dimensional structure of the mutant SLC29A3 protein. These analyses were conducted with the aim of providing valuable insights into the functional implications of the identified mutation on the structure and function of the SLC29A3 protein., Conclusion: Our study contributes to the expanding body of evidence supporting the association between mutations in the SLC29A3 gene and H syndrome. The molecular analysis of diseases related to SLC29A3 is crucial in understanding the range of variability and raising awareness of H syndrome, with the ultimate goal of facilitating early diagnosis and appropriate treatment. The discovery of this novel biallelic variant in the probands further underscores the significance of utilizing genetic testing approaches, such as WES, as dependable diagnostic tools for individuals with this particular condition., (© 2024. The Author(s).)

BACKGROUND H syndrome is an autosomal recessive disorder of histiocytic proliferation with clinical spectrum of unique cutaneous and systemic manifestations. There is no consistent treatment for the disease, and all available options are based on case reports. Here, we present the chronological progression of a case of H syndrome with typical cutaneous manifestations that was misdiagnosed early as meningitis-induced sensorineural hearing loss and later as a non-defined autoimmune connective tissue disease. A new tried, although failed, treatment option is described as well. CASE REPORT A 31-year-old Saudi woman born of a consanguineous marriage presented to our dermatology clinic with symmetrical indurated hyperpigmented to violaceous plaques over the medial thighs, upper legs, lower back, volar wrists, and upper arms, associated with hypertrichosis. Hallux valgus of the big toes was clinically detected as well. She had a history of sensorineural deafness, diabetes mellitus, chronic anemia, and hypothyroidism. Genetic analysis of the patient showed a homozygous frameshift pathogenic variant of the SLC29A3 gene, c.243del p.(Lys81Asnfs*20). Systemic treatments in the form of methotrexate and imatinib had been tried; however, both failed to control her sclerotic cutaneous changes. CONCLUSIONS Knowing the early life presentation and the variable clinical symptoms of H syndrome is crucial in early intervention and further prevention of the non-reversible changes. Moreover, avoiding unnecessary immunosuppressive medication use is warranted in certain circumstances.

Background: The H syndrome is an autosomal recessive disease characterized by hyperpigmentation, hypertrichosis and sensorineural hearing loss., Methods: A mutation in the coding of the human equilibrative nucleoside transporter 3 (hENT3) within the SLC29A3 gene on chromosome 10q22 leads to the manifestation of this disease. In this report, we present two cases of H syndrome., Results: The first patient exhibits hyperpigmentation, hypogonadism, Type 1 diabetes mellitus, arthritis and osteoporosis. The second patient experiences hyperpigmentation, hypertrichosis, osteopenia and hypogonadism., Conclusion: Our objective is to broaden the clinical spectrum of H syndrome, highlighting the involvement of arthritis, hyperinflammation and low bone mineral density in individuals with this disorder., (© 2024 Australasian College of Dermatologists.)

Objective: This study aims to identify causal variants associated with vitiligo in an expanded region of 10q22.1. Materials and Methods: We conducted a fine-scale deep analysis of the expanded 10q22.1 region using in a large genome-wide association studies dataset consisting of 1117 cases and 1701 controls through imputation. We selected five nominal coding single nucleotide polymorphisms (SNPs) located in SLC29A3 and CDH23 and genotyped them in an independent cohort of 2479 cases and 2451 controls in a Chinese Han population cohort using the Sequenom MassArray iPLEX1 system. Results: A missense SNP in SLC29A3 , rs2252996, showed strong evidence of association with vitiligo ( p  = 1.34 × 10 -8 , odds ratio [OR] = 0.82). Three synonymous SNPs (rs1084004 in SLC29A3 ; rs12218559 and rs10999978 in CDH23 ) provided suggestive evidence of association for vitiligo ( p  = 1.69 × 10 -6 , OR = 0.84; p  = 9.47 × 10 -5 , OR = 1.18; p  = 6.90 × 10 -4 , OR = 1.16, respectively). Stepwise conditional analyses identified two significant independent disease-associated signals from the four SNPs (both p  < 0.05; both D' = 0.03; and r 2  = 0.00). Conclusion: The study identifies four genetic coding variants in SLC29A3 and CDH23 on 10q22.1 that may contribute to vitiligo susceptibility with one missense variant affecting disease subphenotypes. The presence of multiple genetic variants underscores their significant role in the genetic pathogenesis of the disease.

Aims: Diet quality might influence cardiometabolic health through epigenetic changes, but this has been little investigated in adults. Our aims were to identify cytosine-phosphate-guanine (CpG) dinucleotides associated with diet quality by conducting an epigenome-wide association study (EWAS) based on blood DNA methylation (DNAm) and to assess how diet-related CpGs associate with inherited susceptibility to cardiometabolic traits: body mass index (BMI), systolic blood pressure (SBP), triglycerides, type 2 diabetes (T2D), and coronary heart disease (CHD)., Methods and Results: Meta-EWAS including 5274 participants in four cohorts from Spain, the USA, and the UK. We derived three dietary scores (exposures) to measure adherence to a Mediterranean diet, to a healthy plant-based diet, and to the Dietary Approaches to Stop Hypertension. Blood DNAm (outcome) was assessed with the Infinium arrays Human Methylation 450K BeadChip and MethylationEPIC BeadChip. For each diet score, we performed linear EWAS adjusted for age, sex, blood cells, smoking and technical variables, and BMI in a second set of models. We also conducted Mendelian randomization analyses to assess the potential causal relationship between diet-related CpGs and cardiometabolic traits. We found 18 differentially methylated CpGs associated with dietary scores (P < 1.08 × 10-7; Bonferroni correction), of which 12 were previously associated with cardiometabolic traits. Enrichment analysis revealed overrepresentation of diet-associated genes in pathways involved in inflammation and cardiovascular disease. Mendelian randomization analyses suggested that genetically determined methylation levels corresponding to lower diet quality at cg02079413 (SNORA54), cg02107842 (MAST4), and cg23761815 (SLC29A3) were causally associated with higher BMI and at cg05399785 (WDR8) with greater SBP, and methylation levels associated with higher diet quality at cg00711496 (PRMT1) with lower BMI, T2D risk, and CHD risk and at cg0557921 (AHRR) with lower CHD risk., Conclusion: Diet quality in adults was related to differential methylation in blood at 18 CpGs, some of which related to cardiometabolic health., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

As a crucial gene associated with diseases, the SLC29A3 gene encodes the equilibrative nucleoside transporter 3 (ENT3). ENT3 plays an essential regulatory role in transporting intracellular hydrophilic nucleosides, nucleotides, hydrophilic anticancer and antiviral nucleoside drugs, energy metabolism, subcellular localization, protein stability, and signal transduction. The mutation and inactivation of SLC29A3 are intimately linked to the occurrence, development, and prognosis of various human tumors. Moreover, many hereditary human diseases, such as H syndrome, pigmentary hypertrichosis and non-autoimmune insulin-dependent diabetes mellitus (PHID) syndrome, Faisalabad histiocytosis (FHC), are related to SLC29A3 mutations. This review explores the mechanisms of SLC29A3 mutations and expression alterations in inherited disorders and cancers. Additionally, we compile studies on the inhibition of ENT3, which may serve as an effective strategy to potentiate the anticancer activity of chemotherapy. Thus, the synopsis of genetics, permeant function and drug therapy of ENT3 provides a new theoretical and empirical foundation for the diagnosis, prognosis of evaluation and treatment of various related diseases., Competing Interests: Declaration of competing interest The authors declare they have no competing interests., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Aims/hypothesis: Monogenic diabetes is estimated to account for 1-6% of paediatric diabetes cases in primarily non-consanguineous populations, while the incidence and genetic spectrum in consanguineous regions are insufficiently defined. In this single-centre study we aimed to evaluate diabetes subtypes, obtain the consanguinity rate and study the genetic background of individuals with syndromic and neonatal diabetes in a population with a high rate of consanguinity., Methods: Data collection was carried out cross-sectionally in November 2021 at the paediatric diabetic clinic, Dr Jamal Ahmad Rashed Hospital, in Sulaimani, Kurdistan, Iraq. At the time of data collection, 754 individuals with diabetes (381 boys) aged up to 16 years were registered. Relevant participant data was obtained from patient files. Consanguinity status was known in 735 (97.5%) participants. Furthermore, 12 families of children with neonatal diabetes and seven families of children with syndromic diabetes consented to genetic testing by next-generation sequencing. Prioritised variants were evaluated using the American College of Medical Genetics and Genomics guidelines and confirmed by Sanger sequencing., Results: A total of 269 of 735 participants (36.5%) with known consanguinity status were offspring of consanguineous families. An overwhelming majority of participants (714/754, 94.7%) had clinically defined type 1 diabetes (35% of them were born to consanguineous parents), whereas only eight (1.1%) had type 2 diabetes (38% consanguineous). Fourteen (1.9%) had neonatal diabetes (50% consanguineous), seven (0.9%) had syndromic diabetes (100% consanguineous) and 11 (1.5%) had clinically defined MODY (18% consanguineous). We found that consanguinity was significantly associated with syndromic diabetes (p=0.0023) but not with any other diabetes subtype. The genetic cause was elucidated in ten of 12 participants with neonatal diabetes who consented to genetic testing (homozygous variants in GLIS3 [sibling pair], PTF1A and ZNF808 and heterozygous variants in ABCC8 and INS) and four of seven participants with syndromic diabetes (homozygous variants in INSR, SLC29A3 and WFS1 [sibling pair]). In addition, a participant referred as syndromic diabetes was diagnosed with mucolipidosis gamma and probably has type 2 diabetes., Conclusions/interpretation: This unique single-centre study confirms that, even in a highly consanguineous population, clinically defined type 1 diabetes is the prevailing paediatric diabetes subtype. Furthermore, a pathogenic cause of monogenic diabetes was identified in 83% of tested participants with neonatal diabetes and 57% of participants with syndromic diabetes, with most variants being homozygous. Causative genes in our consanguineous participants were markedly different from genes reported from non-consanguineous populations and also from those reported in other consanguineous populations. To correctly diagnose syndromic diabetes in consanguineous populations, it may be necessary to re-evaluate diagnostic criteria and include additional phenotypic features such as short stature and hepatosplenomegaly., (© 2023. The Author(s).)

Histiocytoses are inflammatory myeloid neoplasms often driven by somatic activating mutations in mitogen-activated protein kinase (MAPK) cascade genes. H syndrome is an inflammatory genetic disorder caused by germ line loss-of-function mutations in SLC29A3, encoding the lysosomal equilibrative nucleoside transporter 3 (ENT3). Patients with H syndrome are predisposed to develop histiocytosis, yet the mechanism is unclear. Here, through phenotypic, molecular, and functional analysis of primary cells from a cohort of patients with H syndrome, we reveal the molecular pathway leading to histiocytosis and inflammation in this genetic disorder. We show that loss of function of ENT3 activates nucleoside-sensing toll-like receptors (TLR) and downstream MAPK signaling, inducing cytokine secretion and inflammation. Importantly, MEK inhibitor therapy led to resolution of histiocytosis and inflammation in a patient with H syndrome. These results demonstrate a yet-unrecognized link between a defect in a lysosomal transporter and pathological activation of MAPK signaling, establishing a novel pathway leading to histiocytosis and inflammation., (© 2023 by The American Society of Hematology.)

Importance: Alphaviruses threaten public health continuously, and Getah virus (GETV) is a re-emerging alphavirus that can potentially infect humans. Approved antiviral drugs and vaccines against alphaviruses are few available, but several host antiviral factors have been reported. Here, we used GETV as a model of alphaviruses to screen for additional host factors. Tetrachlorodibenzo-p-dioxin-inducible poly(ADP ribose) polymerase was identified to inhibit GETV replication by inducing ubiquitination of the glycoprotein E2, causing its degradation by recruiting the E3 ubiquitin ligase membrane-associated RING-CH8 (MARCH8). Using GETV as a model virus, focusing on the relationship between viral structural proteins and host factors to screen antiviral host factors provides new insights for antiviral studies on alphaviruses., Competing Interests: The authors declare no conflict of interest.

The purinergic signaling molecule adenosine (Ado) modulates many physiological and pathological functions in the brain. However, the exact source of extracellular Ado remains controversial. Here, utilizing a newly optimized genetically encoded GPCR-Activation-Based Ado fluorescent sensor (GRAB Ado ), we discovered that the neuronal activity-induced extracellular Ado elevation is due to direct Ado release from somatodendritic compartments of neurons, rather than from the axonal terminals, in the hippocampus. Pharmacological and genetic manipulations reveal that the Ado release depends on equilibrative nucleoside transporters but not the conventional vesicular release mechanisms. Compared with the fast-vesicular glutamate release, the Ado release is slow (~40 s) and requires calcium influx through L-type calcium channels. Thus, this study reveals an activity-dependent second-to-minute local Ado release from the somatodendritic compartments of neurons, potentially serving modulatory functions as a retrograde signal.

By lacking de novo purine biosynthesis enzymes, Plasmodium falciparum requires purine nucleoside uptake from host cells. The indispensable nucleoside transporter ENT1 of P. falciparum facilitates nucleoside uptake in the asexual blood stage. Specific inhibitors of PfENT1 prevent the proliferation of P. falciparum at submicromolar concentrations. However, the substrate recognition and inhibitory mechanism of PfENT1 are still elusive. Here, we report cryo-EM structures of PfENT1 in apo, inosine-bound, and inhibitor-bound states. Together with in vitro binding and uptake assays, we identify that inosine is the primary substrate of PfENT1 and that the inosine-binding site is located in the central cavity of PfENT1. The endofacial inhibitor GSK4 occupies the orthosteric site of PfENT1 and explores the allosteric site to block the conformational change of PfENT1. Furthermore, we propose a general "rocker switch" alternating access cycle for ENT transporters. Understanding the substrate recognition and inhibitory mechanisms of PfENT1 will greatly facilitate future efforts in the rational design of antimalarial drugs., (© 2023. The Author(s).)

An increasing amount of evidence emphasizes the role of metabolic reprogramming in immune cells to fight infections. However, little is known about the regulation of metabolite transporters that facilitate and support metabolic demands. In this study, we found that the expression of equilibrative nucleoside transporter 3 (ENT3, encoded by solute carrier family 29 member 3, Slc29a3) is part of the innate immune response, which is rapidly upregulated upon pathogen invasion. The transcription of Slc29a3 is directly regulated by type I interferon-induced signaling, demonstrating that this metabolite transporter is an interferon-stimulated gene (ISG). Suprisingly, we unveil that several viruses, including SARS-CoV-2, require ENT3 to facilitate their entry into the cytoplasm. The removal or suppression of Slc29a3 expression is sufficient to significantly decrease viral replication in vitro and in vivo. Our study reveals that ENT3 is a pro-viral ISG co-opted by some viruses to gain a survival advantage., (© 2023 The Authors. Published under the terms of the CC BY NC ND 4.0 license.)

Dysosteosclerosis (DSS) refers to skeletal dysplasias that radiographically feature focal appendicular osteosclerosis with variable platyspondyly. Genetic heterogeneity is increasingly reported for the DSS phenotype and now involves mutations of SLC29A3, TNFRSF11A, TCIRG1, LRRK1, and CSF1R. Typical radiological findings are widened radiolucent long bones with thin cortices yet dense irregular metaphyses, flattened vertebral bodies, dense ribs, and multiple fractures. However, the radiographic features of DSS evolve, and the metaphyseal and/or appendicular osteosclerosis variably fades with increasing patient age, likely due to some residual osteoclast function. Fractures are the principal presentation of DSS, and may even occur in infancy with SLC29A3-associated DSS. Cranial base sclerosis can lead to cranial nerve palsies such as optic atrophy, and may be the initial presentation, though not observed with SLC29A3-associated DSS. Gene-specific extra-skeletal features can be the main complication in some forms of DSS such as CSF1R- associated DSS. Further genetic heterogeneity is likely, especially for X-linked recessive DSS and cases currently with an unknown genetic defect. Distinguishing DSS can be challenging due to variable clinical and radiological features and an evolving phenotype. However, defining the DSS phenotype is important for predicting complications, prognosis, and instituting appropriate health surveillance and treatment., Competing Interests: Declaration of competing interest None., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Elevated intraocular pressure (IOP) is the major risk factor for glaucoma. The molecular mechanism of elevated IOP is unclear, which impedes glaucoma therapy. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible Poly-ADP-ribose Polymerase (TIPARP), a member of the PARP family, catalyses mono-ADP-ribosylation. Here we showed that TIPARP was widely expressed in the cornea, trabecular meshwork, iris, retina, optic nerve, sclera, and choroid of human eyes. The expression of TIPARP was significantly upregulated in the blood and trabecular meshwork of patients with primary open angle glaucoma compared with that of healthy controls. Transcriptome analysis revealed that the expression of genes related to extracellular matrix deposition and cell adhesion was decreased in TIPARP-upregulated human trabecular meshwork (HTM) cells. Moreover, western blot analysis showed that collagen types I and IV, fibronectin, and α-SMA were increased in TIPARP-downregulated or TIPARP-inhibited HTM cells. In addition, cross-linked actin networks were produced, and vinculin was upregulated in these cells. Subconjunctival injection of the TIPARP inhibitor RBN-2397 increased the IOP in Sprague-Dawley rats. Therefore, we identified TIPARP as a regulator of IOP through modulation of extracellular matrix and cell cytoskeleton proteins in HTM cells. These results indicate that TIPARP is a potential therapeutic target for ocular hypertension and glaucoma., (© 2022. The Author(s).)

Background: Mature cystic teratomas of the ovary are the most common type of germ cell tumor, comprising 33% of ovarian tumors. Studying these tumors may result in a better understanding of their stepwise developmental processes and molecular bases and provide useful information for the development of tissue-engineering technologies., Methods: In the present study, 9 mature cystic teratomas of the ovary were analyzed by whole-exome sequencing and the results were compared with the Catalogue of Somatic Mutations in Cancer and dbSNP databases., Results: Mutations were validated in 15 genes with alterations in all 9 (100%) samples and changes in protein coding. The top 10 mutated genes were FLG, MUC17, MUC5B, RP1L1, NBPF1, GOLGA6L2, SLC29A3, SGK223, PTGFRN, and FAM186A. Moreover, 7 variants in exons with changes in protein coding are likely of importance in the development of mature cystic teratomas of the ovary, namely PTGFRN, DUSP5, MPP2, PHLDA1, PRR21, GOLGA6L2, and KRTAP4-2., Conclusions: These genetic alterations may play an important etiological role in teratoma formation. Moreover, novel mutations in DUSP5 and PHLDA1 genes found on whole-exome sequencing may help to explain the characteristics of teratomas., (© 2022. The Author(s).)

Leprosy is a chronic infection of the skin and peripheral nerves caused by Mycobacterium leprae. Despite recent improvements in disease control, leprosy remains an important cause of infectious disability globally. Large-scale genetic association studies in Chinese, Vietnamese and Indian populations have identified over 30 susceptibility loci for leprosy. There is a significant burden of leprosy in Africa, however it is uncertain whether the findings of published genetic association studies are generalizable to African populations. To address this, we conducted a genome-wide association study (GWAS) of leprosy in Malawian (327 cases, 436 controls) and Malian (247 cases, 368 controls) individuals. In that analysis, we replicated four risk loci previously reported in China, Vietnam and India; MHC Class I and II, LACC1 and SLC29A3. We further identified a novel leprosy susceptibility locus at 10q24 (rs2015583; combined p = 8.81 × 10-9; OR = 0.51 [95% CI 0.40 - 0.64]). Using publicly-available data we characterise regulatory activity at this locus, identifying ACTR1A as a candidate mediator of leprosy risk. This locus shows evidence of recent positive selection and demonstrates pleiotropy with established risk loci for inflammatory bowel disease and childhood-onset asthma. A shared genetic architecture for leprosy and inflammatory bowel disease has been previously described. We expand on this, strengthening the hypothesis that selection pressure driven by leprosy has shaped the evolution of autoimmune and atopic disease in modern populations. More broadly, our data highlights the importance of defining the genetic architecture of disease across genetically diverse populations, and that disease insights derived from GWAS in one population may not translate to all affected populations., Competing Interests: The authors have declared that no competing interests exist.

Introduction: SLC29A3 spectrum disorder is an autosomal, recessively inherited, autoinflammatory, multisystem disorder characterized by distinctive cutaneous features, including hyperpigmentation or hypertrichosis, hepatosplenomegaly, hearing loss, cardiac anomalies, hypogonadism, short stature, and insulin-dependent diabetes., Case Presentation: Herein, we report a 6-year-old boy who presented with features resembling type 1 diabetes mellitus, but his clinical course was complicated by IgA nephropathy, pure red cell aplasia, and recurrent febrile episodes. The patient was tested for the presence of pathogenic variants in 53 genes related to monogenic diabetes and found to be compound heterozygous for two SLC29A3 pathogenic variants (p. Arg386Gln and p. Leu298fs)., Conclusion: This case demonstrated that SLC29A3 spectrum disorder should be included in the differential diagnosis of diabetes with atypical comorbidities, even when the distinctive dermatological hallmarks of SLC29A3 spectrum disorder are entirely absent., (© 2022. Hellenic Endocrine Society.)

Toyocamycin (TM) is an adenosine-analog antibiotic isolated from Streptomyces toyocaensis. It inhibits Candida albicans, several plant fungal pathogens, and human cells, but many fungi, including Saccharomyces cerevisiae, are much less susceptible to TM. Aiming to clarify why TM and its analogs tubercidin and 5-iodotubercidin are active against C. albicans but not S. cerevisiae, this study focused on the absence of purine nucleoside transport activity from S. cerevisiae. When the concentrative nucleoside transporter (CNT) of C. albicans was expressed in S. cerevisiae, the recombinant strain became sensitive to TM and its analogs. The expression of C. albicans purine nucleoside permease in S. cerevisiae did not result in sensitivity to TM. Clustered regularly interspaced short palindromic repeat-mediated disruption of CNT was performed in C. albicans. The CNTΔ strain of C. albicans became insensitive to TM and its analogs. These data suggest that the toxicity of TM and its analogs toward C. albicans results from their transport via CNT. Interestingly, S. cerevisiae also became sensitive to TM and its analogs if human CNT3 was introduced into cells. These findings enhance our understanding of the mechanisms of action of adenosine analogs toward Candida pathogens and human cells. IMPORTANCE We investigated the mechanism of toxicity of TM and its analogs to C. albicans. Inspired by the effect of the copresence of TM and purine nucleosides on cell growth of C. albicans, we investigated the involvement of CNT in the toxicity mechanism by expressing CNT of C. albicans (CaCNT) in S. cerevisiae and deleting CaCNT in C. albicans. Our examinations clearly demonstrated that CaCNT is responsible for the toxicity of TM to C. albicans. S. cerevisiae expressing the human ortholog of CaCNT also became sensitive to TM and its analogs, and the order of effects of the TM analogs was a little different between CaCNT- and hCNT3-expressing S. cerevisiae. These findings are beneficial for an understanding of the mechanisms of action of adenosine analogs toward Candida pathogens and human cells and also the development of new antifungal drugs.

Nucleoside transport is essential for maintaining intracellular nucleoside and nucleobase homeostasis for living cells. Here, we identified an uncharacterized GntR/HutC family transcriptional regulator, NagR2, renamed NupR (nucleoside permease regulator), that mainly controls nucleoside transport in the Bacillus thuringiensis BMB171 strain. The deletion or overexpression of nupR affected the bacteria's utilization of guanosine, adenosine, uridine, and cytidine rather than thymidine. We further demonstrated that zinc ion is an effector for the NupR, dissociating NupR from its target DNA. Moreover, the expression of nupR is inhibited by NupR, ComK, and PurR, while it is promoted by CcpA. Also, a purine riboswitch located in its 5' noncoding region influences the expression of nupR . Guanine is the ligand of the riboswitch, reducing the expression of nupR by terminating the transcription of nupR in advance. Hence, our results reveal an exquisite regulation mechanism enabling NupR to respond to multiple signals, control genes involved in nucleoside transport, and contribute to nucleoside substance utilization. Overall, this study provides essential clues for future studies exploring the function of the NupR homolog in other bacteria, such as Bacillus cereus, Bacillus anthracis, Klebsiella pneumoniae, and Streptococcus pneumoniae. IMPORTANCE The transport of nucleosides and their homeostasis within the cell are essential for growth and proliferation. Here, we have identified a novel transcription factor, NupR, which, to our knowledge, is the first GntR family transcription factor primarily involved in the regulation of nucleoside transport. Moreover, responding to diverse intracellular signals, NupR regulates nucleoside transport. It is vital for utilizing extracellular nucleosides and maintaining intracellular nucleoside homeostasis. NupR may also be involved in other pathways such as pH homeostasis, molybdenum cofactor biosynthesis, nitrate metabolism, and transport. In addition, nucleosides have various applications, such as antiviral drugs. Thus, the elucidation of the transport mechanism of nucleosides could be helpful for the construction of engineered strains for nucleoside production.

The proper regulation of nucleotide pools is essential for all types of cellular functions and depends on de novo nucleotide biosynthesis, salvage, and degradation pathways. Despite the apparent essentiality of these processes, a significant number of rare diseases associated with mutations in genes encoding various enzymes of these pathways have been already identified, and others are likely yet to come. However, knowledge on genetic alterations impacting on nucleoside and nucleobase transporters is still limited. At this moment three gene-encoding nucleoside and nucleobase transporter proteins have been reported to be mutated in humans, SLC29A1 , SLC29A3 , and SLC28A1 , impacting on the expression and function of ENT1, ENT3, and CNT1, respectively. ENT1 alterations determine Augustine-null blood type and cause ectopic calcification during aging. ENT3 deficiency translates into various clinical manifestations and syndromes, altogether listed in the OMIM catalog as histiocytosis-lymphoadenopathy plus syndrome (OMIM#602782). CNT1 deficiency causes uridine-cytidineuria (URCTU) (OMIM#618477), a unique type of pyrimidineuria with an as yet not well-known clinical impact. Increasing knowledge on the physiological, molecular and structural features of these transporter proteins is helping us to better understand the biological basis behind the biochemical and clinical manifestations caused by these deficiencies. Moreover, they also support the view that some metabolic compensation might occur in these disturbances, because they do not seem to significantly impact nucleotide homeostasis, but rather other biological events associated with particular subtypes of transporter proteins.

Tocilizumab is reported to reduce systemic inflammation in individuals with SLC29A3 spectrum disorder, but its effect on hearing loss has not been described. The authors present a boy toddler with a history of prematurity, dysphagia, hypersplenism, hyperpigmentation, short height and hearing loss who was referred to the immunology clinic. He initially presented shortly after birth with abnormal hearing screens followed by positive urine test for cytomegalovirus. However, the infection was determined to be postnatally acquired and hearing loss most likely from genetic causes given a family history of hearing loss and consanguinity. A pathogenic variant in SLC29A3 was found on whole-exome sequencing and given concern for SLC29A3 spectrum disorder, steroids were started. Following concerns for development of side effects with chronic steroid use, he was switched to interleukin 6 inhibitor therapy. The patient's inflammatory markers decreased on tocilizumab, and his sensorineural hearing loss was notable for improvement and stabilisation on therapy., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

A woman in her 20s, symptomatic since the age of 4 with short stature, hearing loss, skin hyperpigmentation and induration over the medial aspect of the thigh, hypertrichosis, histiocytes on biopsy, lymphadenopathy, dilated scleral vessels, pancreatic exocrine deficiency, pericardial thickening, swelling of the eyelids and resistant retroperitoneal fibrosis. Whole-genome sequencing showed a mutation in SLC29A3, confirming 'H'-syndrome. She is on steroids and methotrexate. This case highlights the rheumatological mimics of this rare disorder., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To evaluate the pattern of equiliberative nucleoside transporters in viral hepatitis responding and non-responding patients, to correlate the liver fibrosis stage with the pattern among the non-responders, and to correlate the equiliberative nucleoside transporter status with housekeeping hypoxanthine-guanine phosphoribosyltransferase gene., Method: The comparative cross-sectional study was conducted at the Molecular Biology and Genetics Department, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan, from March to August 2018, and comprised adult hepatitis C virus patients of either gender who completed six months of treatment. They were assessed for response to therapy in terms of the presence of the viral load in their serum by using real time polymerase chain reaction, and divided into responder group A and non-responder group B. The groups were compared and correlation between equiliberative nucleoside transporter expressions and liver fibrosis was evaluated. Data was analysed using SPSS 23., Results: Of the 80 patients, 33(41.3%) were males and 47(58.8%) were females. The overall mean age was 37.46±10.61 years. In terms of response to treatment, there were 40(50%) in each of the two groups. Mean post-treatment duration was 15.38±30.09 weeks. Age was not significantly different with respect to gender (p>0.05), but the age pattern was significantly different between the two groups (p<0.001). Also, non-responders had significant post-treatment duration compared to the responders (p<0.001). Hypoxanthine-guanine phosphoribosyltransferase gene showed no significant difference between the groups (p=0.144). Equiliberative nucleoside transporter was significantly down-regulated in the non-responders (p<0.001) and showed correlation with the degree of liver fibrosis (p<0.034) compared to the responders., Conclusions: There was a significant association between equiliberative nucleoside transporters and liver fibrosis stage in hepatitis C virus non-responding patients.

Objective: Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease with differences in prevalence and severity among ancestral groups. This study was undertaken to identify novel genetic components, either shared by or distinct between Asian and European populations., Methods: Both trans-ancestral and ancestry-specific meta-analyses of genome-wide association studies (GWAS) for SLE were performed, involving 30,604 participants of European, Chinese, or Thai origin. Using public epigenomic data and expression quantitative trait loci, fine-mapping analyses were conducted to identify putative causal variants and genes for the newly identified loci. Performance of polygenic risk scores for the Thai cohort was evaluated by comparing different training data., Results: A 1-bp deletion upstream of IFNLR1 was found to be associated with SLE, with the risk allele correlated with increased expression of IFNLR1. This gene encodes interferon-λ (IFNλ) receptor 1, providing evidence of a role of type III IFN signaling in SLE. An intronic variant in SLC29A3 was found to be associated with SLE in Asians only. The putative risk variant may modulate SLC29A3 expression in a monocyte-specific manner. SLC29A3 encodes a lysosomal nucleoside transporter, and subsequent analyses suggested that reduced lysosomal function and phagocytosis might be the mechanism underlying this association. Ancestry-shared loci in or near TAOK3, CHD9, CAMK1D, ATXN1, and TARBP1 and Asian-specific loci close to PEX2, FCHSD2, and TMEM116 also reached the genome-wide significant association with SLE. In addition, trans-ancestral meta-analysis was shown to be valuable in risk prediction for individuals without ancestry-matched data., Conclusion: In this study both shared and Asian-specific loci for SLE were identified, and functional annotation provided evidence of the involvement of increased type III IFN signaling and reduced lysosomal function in SLE., (© 2021 American College of Rheumatology.)

Toxoplasma gondii is unable to synthesize purines de novo, instead salvages them from its environment, inside the host cell, for which they need high affinity carriers. Here, we report the expression of a T. gondii Equilibrative Nucleoside Transporter, Tg244440, in a Trypanosoma brucei strain from which nucleobase transporters have been deleted. Tg244440 transported hypoxanthine and guanine with similar affinity ( K m ~1 µM), while inosine and guanosine displayed K i values of 4.05 and 3.30 µM, respectively. Low affinity was observed for adenosine, adenine, and pyrimidines, classifying Tg244440 as a high affinity oxopurine transporter. Purine analogues were used to probe the substrate-transporter binding interactions, culminating in quantitative models showing different binding modes for oxopurine bases, oxopurine nucleosides, and adenosine. Hypoxanthine and guanine interacted through protonated N1 and N9, and through unprotonated N3 and N7 of the purine ring, whereas inosine and guanosine mostly employed the ribose hydroxy groups for binding, in addition to N1H of the nucleobase. Conversely, the ribose moiety of adenosine barely made any contribution to binding. Tg244440 is the first gene identified to encode a high affinity oxopurine transporter in T. gondii and, to the best of our knowledge, the first purine transporter to employ different binding modes for nucleosides and nucleobases.

Trichomoniasis is a common and widespread sexually-transmitted infection, caused by the protozoan parasite Trichomonas vaginalis. T. vaginalis lacks the biosynthetic pathways for purines and pyrimidines, making nucleoside metabolism a drug target. Here we report the first comprehensive investigation into purine and pyrimidine uptake by T. vaginalis. Multiple carriers were identified and characterized with regard to substrate selectivity and affinity. For nucleobases, a high-affinity adenine transporter, a possible guanine transporter and a low affinity uracil transporter were found. Nucleoside transporters included two high affinity adenosine/guanosine/uridine/cytidine transporters distinguished by different affinities to inosine, a lower affinity adenosine transporter, and a thymidine transporter. Nine Equilibrative Nucleoside Transporter (ENT) genes were identified in the T. vaginalis genome. All were expressed equally in metronidazole-resistant and -sensitive strains. Only TvagENT2 was significantly upregulated in the presence of extracellular purines; expression was not affected by co-culture with human cervical epithelial cells. All TvagENTs were cloned and separately expressed in Trypanosoma brucei. We identified the main broad specificity nucleoside carrier, with high affinity for uridine and cytidine as well as purine nucleosides including inosine, as TvagENT3. The in-depth characterization of purine and pyrimidine transporters provides a critical foundation for the development of new anti-trichomonal nucleoside analogues., (© 2021 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.)

Background: Mutations in the SLC29A3 gene, which encodes the nucleoside transporter hENT3, have been implicated in syndromic forms of histiocytosis including H syndrome, pigmented hypertrichosis with insulin-dependent diabetes, Faisalabad histiocytosis and Familial Rosai-Dorfman disease (RDD). Herein, we report five new patients from a single family who present with phenotypes that associate features of H syndrome and Familial Rosai-Dorfman disease., Methods: We investigated the clinical, biochemical, histopathological and molecular findings in five Tunisian family members' diagnosed with Familial RDD and/or H syndrome. The solute carrier family 29 (nucleoside transporters), member 3 (SLC29A3) gene was screened for molecular diagnosis using direct Sanger sequencing., Results: Genetic analysis of all affected individuals revealed a previously reported missense mutation c.1088 G > A [p.Arg363Gln] in exon 6 of the SLC29A3 gene. Four affected members presented with clinical features consistent with the classical H syndrome phenotype. While their cousin's features were in keeping with Familial Rosai-Dorfman disease diagnosis with a previously undescribed cutaneous RDD presenting as erythematous nodular plaques on the face. This report underlines the clinical variability of SLC29A3 disorders even with an identical mutation in the same family., Conclusion: We report a rare event of 5 Tunisian family members' found to be homozygous for SLC29A3 gene mutations but showing a different phenotype severity. Our study reveals that despite a single mutation, the clinical expression of the SLC29A3 disorders may be significantly heterogeneous suggesting a poor genotype-phenotype correlation for the disease., (© 2021. The Author(s).)

PARP7 is a monoPARP that catalyzes the transfer of single units of ADP-ribose onto substrates to change their function. Here, we identify PARP7 as a negative regulator of nucleic acid sensing in tumor cells. Inhibition of PARP7 restores type I interferon (IFN) signaling responses to nucleic acids in tumor models. Restored signaling can directly inhibit cell proliferation and activate the immune system, both of which contribute to tumor regression. Oral dosing of the PARP7 small-molecule inhibitor, RBN-2397, results in complete tumor regression in a lung cancer xenograft and induces tumor-specific adaptive immune memory in an immunocompetent mouse cancer model, dependent on inducing type I IFN signaling in tumor cells. PARP7 is a therapeutic target whose inhibition induces both cancer cell-autonomous and immune stimulatory effects via enhanced IFN signaling. These data support the targeting of a monoPARP in cancer and introduce a potent and selective PARP7 inhibitor to enter clinical development., Competing Interests: Declaration of interests J.M.G., M.M.V., R.P.A., K.K., K.G.K.-B., B.G., A.Z.L., J.R. Molina, E.M., K.K.S., T.J.W., D.J.B., C.R.M., Y.R., M.N., Z.A.V., S.P.N., E.B., J.-R. Mo, W.D.C., A.S.A.M., J.S., L.U., K.W.K., V.M.R., and H.K. are all employees and shareholders of Ribon Therapeutics at the time of data collection. P.E.R. served as a consultant to Ribon Therapeutics, and T.J.M. is a founder and shareholder in Ribon Therapeutics. M.M.V., K.K.S., and K.W.K. are inventors on US Patent Nos. 10550105, 10870641, and 11014913, which are related to RBN-2397 and assigned to Ribon Therapeutics., (Copyright © 2021 Elsevier Inc. All rights reserved.)

H syndrome is a rare autosomal recessive disorder with clinical features comprising: hyperpigmentation, hypertrichosis, hearing loss, heart anomalies, low height, hypogonadism and hepatosplenomegaly. H syndrome results from loss-of-function mutations in SLC29A3 which leads to abnormal proliferation and function of histiocytes. Herein, we discuss the considerable phenotypic heterogeneity detected in a consanguineous Egyptian family comprising of four affected siblings, two of which are monozygotic twin and the possible therapeutics. The phenotypic variability may be attributed to the role of histiocytes in the tissue response to injury. Such variable expressivity of H syndrome renders the diagnosis challenging and delays the management. The different treatment approaches used for this rare entity are reviewed., (© 2021 Wiley Periodicals LLC.)

Many genes in bacterial genomes are of unknown function, often referred to as y-genes. Recently, the analytic methods have divided bacterial transcriptomes into independently modulated sets of genes (iModulons). Functionally annotated iModulons that contain y-genes lead to testable hypotheses to elucidate y-gene function. The inversely correlated expression of a putative transporter gene, ydhC, relative to purine biosynthetic genes, has led to the hypothesis that it encodes a purine-related transporter and revealed a LysR-family regulator, YdhB, with a predicted 23-bp palindromic binding motif. RNA-Seq analysis of a ydhB knockout mutant confirmed the YdhB-dependent activation of ydhC in the presence of adenosine. The deletion of either the ydhC or the ydhB gene led to a substantially decreased growth rate for E. coli in minimal medium with adenosine, inosine, or guanosine as the nitrogen source. Taken together, we provide clear evidence that YdhB activates the expression of the ydhC gene that encodes a purine transporter in E. coli. We propose that the genes ydhB and ydhC be re-named as punR and punC, respectively., (© 2021. The Author(s).)

We recently described a signal transduction pathway that contributes to androgen receptor (AR) regulation based on site-specific ADP-ribosylation by PARP7, a mono-ADP-ribosyltransferase implicated in several human cancers. ADP-ribosylated AR is recognized by PARP9/DTX3L, a heterodimeric complex that contains an ADP-ribose reader (PARP9) and a ubiquitin E3 ligase (DTX3L). Here, we have characterized the cellular and biochemical requirements for AR ADP-ribosylation by PARP7. We found that the reaction requires nuclear localization of PARP7 and an agonist-induced conformation of AR. PARP7 contains a Cys3His1-type zinc finger (ZF), which also is critical for AR ADP-ribosylation. The Parp7 ZF is required for efficient nuclear import by a nuclear localization signal encoded in PARP7, but rescue experiments indicate the ZF makes a contribution to AR ADP-ribosylation that is separable from the effect on nuclear transport. ZF mutations do not detectably reduce PARP7 catalytic activity and binding to AR, but they do result in the loss of PARP7 enhancement of AR-dependent transcription of the MYBPC1 gene. Our data reveals critical roles for AR conformation and the PARP7 ZF in AR ADP-ribosylation and AR-dependent transcription., (© 2021 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

Rosai-Dorfman disease (RDD) typically presents as bulky lymphadenopathy. Somatic mutations in RAS/MAP kinase pathway genes are common but germline mutations are rare. A patient with RDD and exocrine pancreatic insufficiency was found to have a homozygous germline mutation in SLC29A3, which has been associated with the Histiocytosis/Lymphadenopathy Plus Syndrome. His RDD also was positive for a somatic mutation in lymphoid enhancer binding factor 1 (LEF1). The concurrence of RDD and pancreatic insufficiency should raise consideration of SLC29A3 mutations. Other cases will be needed to confirm this observation and a possible contribution of LEF1 to the development of RDD., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Background: H syndrome (HS) is a rare autoinflammatory disease caused by a mutation in the solute carrier family 29, member 3 (SCL29A3) gene. It has a variable clinical presentation and little phenotype-genotype correlation. The pathognomonic sign of HS is cutaneous hyperpigmentation located mainly in the inner thighs and often accompanied by other systemic manifestations. Improvement after tocilizumab treatment has been reported in a few patients with HS. We report the first patient with HS who presented cardiogenic shock, multiorgan infiltration, and digital ischemia., Case Presentation: 8-year-old boy born to consanguineous parents of Moroccan origin who was admitted to the intensive care unit during the Coronavirus Disease-2019 (COVID-19) pandemic with tachypnoea, tachycardia, and oliguria. Echocardiography showed dilated cardiomyopathy and severe systolic dysfunction compatible with cardiogenic shock. Additionally, he presented with multiple organ dysfunction syndrome. SARS-CoV-2 polymerase chain reaction (PCR) and antibody detection by chromatographic immunoassay were negative. A previously ordered gene panel for pre-existing sensorineural hearing loss showed a pathological mutation in the SCL29A3 gene compatible with H syndrome. Computed tomography scan revealed extensive alveolar infiltrates in the lungs and multiple poor defined hypodense lesions in liver, spleen, and kidneys; adenopathy; and cardiomegaly with left ventricle subendocardial nodules. Invasive mechanical ventilation, broad antibiotic and antifungal coverage showed no significant response. Therefore, Tocilizumab as compassionate use together with pulsed intravenous methylprednisolone was initiated. Improvement was impressive leading to normalization of inflammation markers, liver and kidney function, and stabilising heart function. Two weeks later, he was discharged and has been clinically well since then on two weekly administration of Tocilizumab., Conclusions: We report the most severe disease course produced by HS described so far in the literature. Our patient's manifestations included uncommon, new complications such as acute heart failure with severe systolic dysfunction, multi-organ cell infiltrate, and digital ischemia. Most of the clinical symptoms of our patient could have been explained by SARS-CoV-2, demonstrating the importance of a detailed differential diagnosis to ensure optimal treatment. Although the mechanism of autoinflammation of HS remains uncertain, the good response of our patient to Tocilizumab makes a case for the important role of IL-6 in this syndrome and for considering Tocilizumab as a first-line treatment, at least in severely affected patients.

Cytidine is an important raw material for nucleic acid health food and genetic engineering research. In recent years, it has shown irreplaceable effects in anti-virus, anti-tumor, and AIDS drugs. Its biosynthetic pathway is complex and highly regulated. In this study, overexpression of uracil permease and a nucleoside transporter from Bacillus amyloliquefaciens related to cell membrane transport in Escherichia coli strain BG-08 was found to increase cytidine production in shake flask cultivation by 1.3-fold (0.91 ± 0.03 g/L) and 1.8-fold (1.26 ± 0.03 g/L) relative to that of the original strain (0.70 ± 0.03 g/L), respectively. Co-overexpression of uracil permease and a nucleoside transporter further increased cytidine yield by 2.7-fold (1.59 ± 0.05 g/L) compared with that of the original strain. These results indicate that the overexpressed uracil permease and nucleoside transporter can promote the accumulation of cytidine, and the two proteins play a synergistic role in the secretion of cytidine in Escherichia coli.

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.

We present a case of a 25-year-old man who came to our Endocrine Clinic for evaluation of short stature. He had a history of sensorineural hearing loss, hypertrichosis and hyperpigmentation with the thickening of the skin below the hip, gynecomastia and autoimmune haemolytic anaemia. Investigations showed that he had hypergonadotropic hypogonadism. His phenotype was consistent with that of a rare autosomal recessive genodermatosis of 'H-syndrome'. The diagnosis was confirmed by genetic analysis using next-generation sequencing which showed a homozygous mutation in the SLC29A3 gene (variant: c.1330G>T (p.Glu444Ter)) which was confirmed by Sanger sequencing. This is a rare syndrome with around 100 cases reported in world literature. Though the skin manifestations are pathognomonic of the H-syndrome, it has myriad presentations like short stature, insulin-dependent diabetes mellitus, hypogonadism, hypothyroidism, dyslipidaemia, cardiac anomalies and sensorineural hearing loss. We report this case to highlight the constellation of features of this rare syndrome and bring awareness among the physicians to be vigilant about this syndrome., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: H syndrome is a multisystem inflammatory disease caused by mutations in the SLC29A3 gene (OMIM #602782). The protein product, hENT3, is a nucleoside transporter essential for DNA salvage synthesis. Clinical manifestations are hyperpigmentation, hypertrichosis, hepatosplenomegaly, hearing loss, heart anomalies, hypogonadism, short stature, skeletal deformities, and diabetes mellitus. Laboratory findings are consistent with inflammatory processes. Structural kidney anomalies have been described in 6% of patients., Case Reports: Three family members with genetically diagnosed H syndrome (c.1279G>A, p.Gly427Ser). Two of them presented with hypoalbuminemia and nephrotic range proteinuria. Kidney ultrasound was normal. Kidney biopsy performed in one patient presenting with generalized peripheral pitting edema revealed membranous nephropathy. Different treatments including ACE inhibitors, corticosteroids, and immunomodulatory agents failed to improve the clinical outcome., Conclusions: Generalized peripheral pitting edema and glomerulopathy broaden the clinical spectrum of H syndrome. Periodic bloodwork and urinalysis are recommended.

Poly-ADP-ribose polymerases (PARPs) are enzymes that catalyze ADP-ribosylation and play critical roles in normal and disease settings. The PARP family member, PARP7, is a mono-ADP-ribosyltransferase that has been suggested to play a tumor suppressive role in breast, ovarian, and colorectal cancer. Here, we have investigated how androgen signaling regulates PARP7 homeostasis in prostate cancer cells, where PARP7 is a direct target gene of AR. We found that the PARP7 protein is extremely short-lived, with a half-life of 4.5 min. We show that in addition to its transcriptional regulation by AR, PARP7 is subject to androgen-dependent post-transcriptional regulation that increases its half-life to 25.6 min. This contrasts with PARP1, PARP2, PARP9, and PARP14, which do not display rapid turnover and are not regulated by androgen signaling. Androgen- and AR-dependent stabilization of PARP7 leads to accumulation in the nucleus, which we suggest is a major site of action. Mutations in the catalytic domain, the Cys3His1 zinc finger, and WWE (tryptophan-tryptophan-glutamate) domains in PARP7 each reduce the degradation rate of PARP7, suggesting the overall structure of the protein is tuned for its rapid turnover. Our finding that PARP7 is regulated by AR signaling both transcriptionally and post-transcriptionally in prostate cancer cells suggests the dosage of PARP7 protein is subject to tight regulation.

Biallelic mutations in SLC29A3 cause histiocytosis-lymphadenopathy plus syndrome, also known as H syndrome (HS). HS is a complex disorder, with ~ 25% of patients developing autoinflammatory complications consisting of unexplained fevers, persistently elevated inflammatory markers, and unusual lymphadenopathies, with infiltrating CD68 + , S100 + , and CD1a - histiocytes, resembling the immunophenotype found in Rosai-Dorfman disease (RDD). We investigated the transcriptomic profiles of monocytes, non-activated (M0), classically activated (M1), and alternatively activated macrophages (M2) in two patients with HS, one without autoinflammatory (HS1) and one with autoinflammatory complications (HS2). RNA sequencing revealed a dysregulated transcriptomic profile in both HS patients compared to healthy controls (HC). HS2, when compared to HS1, had several differentially expressed genes, including genes associated with lymphocytic-histiocytic predominance (e.g. NINL) and chronic immune activation (e.g. B2M). The transcriptomic and cytokine profiles of HS patients were comparable to patients with SAID with high levels of TNF. SERPINA1 gene expression was found to be upregulated in all patients studied. Moreover, higher levels of IFNγ were found in the serum of both HS patients when compared to HC. Gene ontology (GO) enrichment analysis of the DEGs in HS patients revealed the terms "type I IFN," "IFNγ signaling pathway," and "immune responses" as the top 3 most significant terms for monocytes. Gene expression analysis of lymph node biopsies from sporadic and H syndrome-associated RDD suggests common underlying pathological process. In conclusion, monocytes and macrophages from both HS patients showed transcriptomic profiles similar to SAIDs and also uniquely upregulated IFNγ signature. These findings may help find better therapeutic options for this rare disorder.

Poly(ADP-ribose) polymerase 7 (PARP-7) has emerged as a critically important member of a large enzyme family that catalyzes ADP-ribosylation in mammalian cells. PARP-7 is a critical regulator of the innate immune response. What remains unclear is the mechanism by which PARP-7 regulates this process, namely because the protein targets of PARP-7 mono-ADP-ribosylation (MARylation) are largely unknown. Here, we combine chemical genetics, proximity labeling, and proteome-wide amino acid ADP-ribosylation site profiling for identifying the direct targets and sites of PARP-7-mediated MARylation in a cellular context. We found that the inactive PARP family member, PARP-13-a critical regulator of the antiviral innate immune response-is a major target of PARP-7. PARP-13 is preferentially MARylated on cysteine residues in its RNA binding zinc finger domain. Proteome-wide ADP-ribosylation analysis reveals cysteine as a major MARylation acceptor of PARP-7. This study provides insight into PARP-7 targeting and MARylation site preference., Competing Interests: KR, SB, IK, IS, DH, MR, DG, LD, JM, MN, MC No competing interests declared, (© 2021, Rodriguez et al.)

PARP-7 (TiPARP) is a mono(ADP-ribosyl) transferase whose protein substrates and biological activities are poorly understood. We observed that PARP7 mRNA levels are lower in ovarian cancer patient samples compared to non-cancerous tissue, but PARP-7 protein nonetheless contributes to several cancer-related biological endpoints in ovarian cancer cells (e.g. growth, migration). Global gene expression analyses in ovarian cancer cells subjected to PARP-7 depletion indicate biological roles for PARP-7 in cell-cell adhesion and gene regulation. To identify the MARylated substrates of PARP-7 in ovarian cancer cells, we developed an NAD + analog-sensitive approach, which we coupled with mass spectrometry to identify the PARP-7 ADP-ribosylated proteome in ovarian cancer cells, including cell-cell adhesion and cytoskeletal proteins. Specifically, we found that PARP-7 MARylates α-tubulin to promote microtubule instability, which may regulate ovarian cancer cell growth and motility. In sum, we identified an extensive PARP-7 ADP-ribosylated proteome with important roles in cancer-related cellular phenotypes., Competing Interests: LP, SC, TN, MS, DH, JL No competing interests declared, BG holds the patents on the anti-MAR binding reagent (United States Patent No. 9,599,606) and the asPARP technology (United States Patent No. 9,926,340) described herein. UT Southwestern Medical Center has licensed the anti-MAR binding reagent to EMD Millipore, which markets it for research purposes. BIOLOG Life Science Institute, a coholder of United States Patent No. 9,926,340, sells the NAD+ analog 8-Bu(3-yne)T-NAD+. WK is a founder consultant for Ribon (Therapeutics, Inc). Holds the patents on the anti-MAR binding reagent (United States Patent No. 9,599,606) and the asPARP technology (United States Patent No. 9,926,340) described herein. UT Southwestern Medical Center has licensed the anti-MAR binding reagent to EMD Millipore, which markets it for research purposes. BIOLOG Life Science Institute, a coholder of United States Patent No. 9,926,340, sells the NAD+ analog 8-Bu(3-yne)T-NAD+., (© 2021, Palavalli Parsons et al.)

Nucleoside homeostasis, which is mediated by transporters and channels, is essential for all life on Earth. In Escherichia coli, NupG mediates the transport of nucleosides and was deemed to be the prototype of the nucleoside proton symporter (NHS) family and the major facilitator superfamily. To date, the substrate recognition and transport mechanisms of NHS transporters are still elusive. Here, we report two crystal structures of NupG (WT and D323A NupG) resolved at 3.0 Å. Both structures reveal an identical inward-open conformation. Together with molecular docking and molecular dynamics simulations and in vitro uridine-binding assays, we found that the uridine binding site, which locates in the central cavity between N and C domains of NupG, is constituted by R136, T140, F143, Q225, N228, Q261, E264, Y318, and F322. Moreover, we found that D323 is very important for substrate binding via in vitro uridine-binding assays using D323 mutations, although it does not have a direct contact with uridine. Our structural and biochemical data therefore provide an important framework for the mechanistic understanding of nucleoside transporters of the NHS family., Competing Interests: Conflict of interest The authors declare that no competing interests exist., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)