HINT1 Gene Polymorphisms, Smoking Behaviour, and Personality Traits: A Haplotype Case-Control Study.

The factors influencing the development and maintenance of nicotine dependence are numerous and complex. Recent studies indicate that smokers exhibit distinct genetic predispositions to nicotine dependence. We aimed to analyse (1) the association between rs2551038 and cigarette smoking, (2) the association of between the rs3864236-rs2526303-rs2551038 haplotype and cigarette smoking, and (3) the personality traits measured by the NEO Five-Factor Inventory in cigarette users and never-smokers. No significant differences were present in the frequency of rs2551038 genotypes and alleles in the studied cigarette users compared to the control group. Cigarette users, compared to the control group, had higher scores on the NEO-FFI Extraversion scale (p = 0.0011), and lower scores were obtained by the cigarette users for the NEO-FFI Openness (p = 0.0060), Agreeability (p ≤ 0.000), and Conscientiousness (p ≤ 0.000) scales. There was a significant positive Pearson's linear correlation between the age and the Fagestrom test (r = 0.346; p < 0.0001) and the NEO-FFI Openness scale (r = 0.180; p < 0.0001) in the group of cigarette users. We observed significant linkage disequilibrium between rs2526303 and rs3864236 (D' = 0.3581; p < 2.2204 × 10-16) and between rs2526303 and rs2551038 (D' = 0.9993; p < 2.2204 × 10-16) in the tested sample. The sex-stratified haplotype analysis revealed that in the group of male never-smokers, the GTC haplotype was significantly more frequent than in the group of cigarette users (38% vs. 22%; p = 0.0039). The presented study reveals significant differences in personality trait scores between cases and controls. Moreover, the sex-stratified analysis showed significant differences in haplotype distribution. These results underscore the interplay between genetic predisposition, sex, and personality in nicotine-using individuals.

The HINT1 Gene rs2526303 Polymorphism and Its Association with Personality Traits in Cigarette Smokers.

The development of a substance use disorder (SUD) is a multifaceted process influenced by both genetic and environmental factors. Recent research has suggested the potential involvement of the HINT1 gene in various aspects of plasticity, mood regulation, anxiety-like behaviour, and stress-coping mechanisms. Moreover, personality traits are also recognised to be instrumental in developing substance dependency. Given these considerations, our study investigated the associations among cigarette smoking, personality traits, and the rs2526303 polymorphism. Additionally, we investigated the interactions between personality traits and rs2526303 in the HINT1 gene. The study group comprised 531 volunteers: 375 cigarette users (mean age = 29.42 ± 10.72; F = 49%, M = 51%) and 156 never-smokers (mean age = 26.93 ± 10.09; F = 79%, M = 21%). Genotyping was conducted using the real-time PCR method, and the NEO Five-Factor Personality Inventory and State-Trait Anxiety Inventory were administered. There were no statistically significant differences in the frequency of rs2526303 genotypes and alleles in the cigarette user group compared to the control group. Compared to the control group, the cigarette users obtained higher scores in the assessment of the NEO-FFI Extraversion scale and lower results for the NEO-FFI Openness, Agreeableness, and Conscientiousness scales. Additionally, there was a statistically significant effect of rs2526303 genotype interaction and cigarette-using status on the conscientiousness scale. These outcomes collectively suggest a notable association between cigarette smoking and specific dimensions of personality, particularly highlighting differences in extraversion, openness, agreeableness, and conscientiousness. Furthermore, the detected interaction effect involving rs2526303 concerning conscientiousness signifies a complex interplay between genetic factors and smoking behaviour.

Autosomal recessive axonal neuropathy with neuromyotonia in a Tibetan family caused by HINT1 gene variation and literature review / 中华实用儿科临床杂志

Objective:To summarize the characteristics of autosomal recessive axonal neuropathy with neuromyotonia (ARAN-NM) caused by HINT1 gene mutation. Methods:Retrospective case summary.Clinical data of 2 Tibetan siblings diagnosed with ARAN-NM in the Department of Pediatrics of Peking University First Hospital in August 2023 were retrospectively analyzed.A review of literature reporting relevant Chinese patients was conducted.Results:The proband and her elder brother were aged 13 and 19, respectively.Both developed abnormal gait at the age of 11, followed by varus, claudication, and weak thumb strength.The proband also had neuromyotonia.Physical examinations showed that the proband and her elder brother had decreased muscle strength of the extremities, mainly in the thumbs and distal ends of lower limbs.The distal muscles of the proband′s lower extremities and the muscles of both hands of the proband′s elder brother were atrophied.Both feet showed talipes equinovarus in the proband and her elder brother.The proband′s electromyography (EMG) showed peripheral nerve injuries (motor and sensory axonal involvement, especially in distal ends) and myotonic potentials.The trio-whole exon sequencing detected homozygous pathogenic variation in HINT1 gene in both the proband and her elder brother, who were diagnosed as ARAN-NM based on c. 169A>G (p.K57E). After the Carbamazepine treatment, the proband′s neuromyotonia, numbness and weakness were relieved.Both the proband and her elder brother underwent orthopaedic surgery and rehabilitation.Their foot deformities and gait were significantly improved.Two Chinese literatures (2 patients) and four English literatures (8 patients) were retrieved.Including the proband and her elder brother in this study, there were 12 ARAN-NM patients, 10 of whom had clinical data.The ages of onset and diagnosis were 2-16 (1 case unknown) and 13-33 years old, respectively.Myasthenia was present in 9 patients, especially in distal ends.Eight patients were complicated with neuromyotonia, nine patients with muscle atrophy, seven patients with foot deformity, and two patients with sensory disturbance.Creatine kinase(CK) was elevated in all 9 patients tested or CK.EMG showed neurogenic injuries in all patients and neuromyotonia discharge in six patients.Three patients were treated with Carbamazepine, and some symptoms were relieved.Missense/nonsense mutations were found in the 12 patients, and the high-frequency variation was c. 112T>C (p.C38R). Conclusions:ARAN-NM is a rare autosomal recessive neuromuscular disease caused by HINT1 gene mutation.There is no ethnic difference in clinical manifestations, mainly distal limb weakness with neuromyotonia.Carbamazepine can alleviate some symptoms, and orthopaedic surgery can improve foot deformity and gait.

Association of the rs3864283 Polymorphism Located in the HINT1 Gene with Cigarette Use and Personality Traits.

Nicotine is the major reinforcing component of tobacco and it is believed that the pharmacological effects of nicotine motivate the initiation and maintenance of a smoking habit. HINT1 appears to play a role in the modulation of the effects of drug abuse. Hence, the aim of this study was the analysis of the association between the rs3864283 polymorphism of the HINT1 gene and cigarette use; the analysis of personality traits assessed by the means of the NEO-FFI Inventory; the analysis of anxiety measured by the STAI questionnaire; and the analysis of the interactions between the rs3864283 and both personality traits and anxiety. The study group consisted of 522 volunteers. Of these, 371 were cigarette users and 151 were never-smokers. The genomic DNA was isolated from venous blood using standard procedures. The results of both inventories, i.e., NEO-FFI and STAI., were reported as the sten scores. Genotyping was conducted with the real-time PCR method. Statistically significant differences were found in the frequency of rs3864283 genotypes and alleles in the tested sample of Cigarette Users when compared to the control group. The Cigarette Users compared to the control group obtained higher scores in the assessment of NEO-FFI extraversion scale, and significantly lower results were obtained for the NEO-FFI openness scale, the agreeableness scale, and the conscientiousness scale. There was a statistically significant effect of rs3864283 genotype interaction and Cigarette Use or not using (control group) on the extraversion scale. There was also a statistically significant effect of Cigarette Users or the control group on the extraversion scale score. The results obtained in the presented study indicated a significant association between the HINT1 rs3864283 variant and smoking status. Moreover, this is the first study incorporating genetic association of above-mentioned polymorphic site with interaction analysis of personality traits and anxiety. Overall, the results of this study suggest that HINT1 is an important genetic component associated with nicotine usage mechanisms.

The most common European HINT1 neuropathy variant phenotype and its case studies.

HINT1 is an ubiquitous homodimeric purine phosphoramidase belonging to the histidine-triad superfamily. In neurons, HINT1 stabilizes the interaction of different receptors and regulates the effects of their signaling disturbances. Changes in HINT1 gene are associated with autosomal recessive axonal neuropathy with neuromyotonia. Aim of the study was detailed description of patients' phenotype with HINT1 homozygous NM_005340.7: c.110G>C (p.Arg37Pro) variant. Seven homozygous and three compound heterozygous patients were recruited and evaluated using standardized tests for CMT patients, in four patients' nerve ultrasonography was performed. The median age of symptom onset was 10 years (range 1-20), with initial complaints being distal lower limb weakness with gait impairment, combined with muscle stiffness, more pronounced in the hands than in the legs and worsened by cold. Arm muscles became involved later, presenting with distal weakness and hypotrophy. Neuromyotonia was present in all reported patients and is thus a diagnostic hallmark. Electrophysiological studies demonstrated axonal polyneuropathy. Impaired mental performance was observed in six out of ten cases. In all patients with HINT1 neuropathy, ultrasound examination showed significantly reduced muscle volume as well as spontaneous fasciculations and fibrillations. The nerve cross-sectional areas of the median and ulnar nerves were closer to the lower limits of the normal values. None of the investigated nerves had structural changes. Our findings broaden the phenotype of HINT1-neuropathy and have implications for diagnostics and ultrasonographic evaluation of HINT1-neuropathy patients.

The oncogenic and immunological roles of histidine triad nucleotide-binding protein 1 in human cancers and their experimental validation in the MCF-7 cell line.

Background: Histidine triad nucleotide binding protein 1 (HINT1) is a haplo-insufficient tumor suppressor gene that plays a significant role in cell proliferation and survival. However, to date, no systematic pan-cancer analysis has been conducted to explore its function in prognosis, and its oncogenic and immunological roles. We also analyzed the role of HINT1 in breast cancer (BC) progression in vitro. Methods: An analysis of the HINT1 expression pattern was performed using the TIMER database. The infiltration of immune cells into several cancer types was also studied using the Xena Shiny tool. To determine the relationship between stemness and the expression of HINT1 mRNA, the Spearman correlation test was used with the SangerBox tool. The correlation between HINT1 and functional states in various cancers was determined from the CancerSEA database. The potential role of HINT1 in BC oncogenesis was also investigated by Western blot and Annexin V/PI assays. Results: The Cancer Genome Atlas pan-cancer data analysis suggested that HINT1 was extensively altered in most tumor tissues but not in most adjacent normal tissues. A high expression of HINT1 was associated with the decreased infiltration of cluster of differentiation (CD)4+ T cells. Importantly, increased HINT1 expression was also associated with a large majority of tumors with high stemness and lower stromal, immune, and estimate scores. Further, the expression of HINT1 was significantly associated with the tumor mutational burden (TMB) and microsatellite instability (MSI) in certain tumor types. Finally, HINT1 overexpression was found to impair BC progression by promoting cell apoptosis. HINT1 upregulation also reduced the expression of microphthalmia transcription factor (MITF) and ß-catenin in BC Michigan Cancer Foundation-7 (MCF-7) cells, and the phosphorylation of protein kinase B (p-Akt). Conclusions: The present study showed that HINT1 plays an oncogenic role in various cancers and could also be used as a biomarker for BC.

Case report: A novel homozygous histidine triad nucleotide-binding protein 1 mutation featuring distal hereditary motor-predominant neuropathy with rimmed vacuoles.

Introduction: Recessive mutations in the gene encoding the histidine triad nucleotide-binding protein 1 (HINT1) are associated with axonal motor-predominant Charcot-Marie-Tooth (CMT) disease with neuromyotonia. A total of 24 HINT1 gene mutations have been reported so far. Some of these cases had mild to moderate elevations of creatinine kinase with no earlier reports of muscle biopsy findings in these cases. In this study, we describe a patient with axonal motor-predominant neuropathy and myopathy with rimmed vacuoles, likely due to a novel HINT1 gene mutation. Case report: A 35-year-old African American man presented with insidious onset and progressive symmetric distal leg weakness followed by hand muscle atrophy and weakness since the age of 25. He had no muscle cramps or sensory complaints. His 38-year-old brother developed similar symptoms beginning in his early 30 s. On neurologic examination, the patient had distal weakness and atrophy in all limbs, claw hands, pes cavus, absent Achilles reflexes, and normal sensory examination. Electrodiagnostic studies revealed absent/reduced compound motor action potential amplitudes distally with normal sensory responses with no neuromyotonia. His sural nerve biopsy showed a chronic non-specific axonal neuropathy, and a biopsy of the tibialis anterior muscle demonstrated myopathic features and several muscle fibers harboring rimmed vacuoles without inflammation in addition to chronic denervation changes. A homozygous variant, p.I63N (c.188T > A), in the HINT1 gene was found in both brothers. Conclusion: We describe a novel, likely pathogenic, HINT1 pI63N (c.188T > A) homozygous variant associated with hereditary axonal motor-predominant neuropathy without neuromyotonia in two African American brothers. The presence of rimmed vacuoles on muscle biopsy raises the possibility that mutations in the HINT1 gene may also cause myopathy.

HINT1 neuropathy in Lithuania: clinical, genetic, and functional profiling.

BACKGROUND: Recessive loss-of-function variations in HINT1 cause a peculiar subtype of Charcot-Marie-Tooth disease: neuromyotonia and axonal neuropathy (NMAN; OMIM[#137200]). With 25 causal variants identified worldwide, HINT1 mutations are among the most common causes of recessive neuropathy. The majority of patients are compound heterozygous or homozygous for a Slavic founder variant (c.110G>C, p.Arg37Pro) that has spread throughout Eurasia and America. RESULTS: In a cohort of 46 genetically unresolved Lithuanian patients with suspected inherited neuropathy, we identified eight families with HINT1 biallelic variations. Most patients displayed sensorimotor or motor-predominant axonal polyneuropathy and were homozygous for the p.Arg37Pro variant. However, in three families we identified a novel variant (c.299A>G, p.Glu100Gly). The same variant was also found in an American patient with distal hereditary motor neuropathy in compound heterozygous state (p.Arg37Pro/p.Glu100Gly). Haplotype analysis demonstrated a shared chromosomal region of 1.9 Mb between all p.Glu100Gly carriers, suggesting a founder effect. Functional characterization showed that the p.Glu100Gly variant renders a catalytically active enzyme, yet highly unstable in patient cells, thus supporting a loss-of-function mechanism. CONCLUSION: Our findings broaden NMAN's genetic epidemiology and have implications for the molecular diagnostics of inherited neuropathies in the Baltic region and beyond. Moreover, we provide mechanistic insights allowing patient stratification for future treatment strategies.

HINT1 neuropathy: Expanding the genotype and phenotype spectrum.

Inherited peripheral neuropathy (IPN) is a heterogeneous group of disorders due to pathogenic variation in more than 100 genes. In 2012, the first cases of IPN associated with HINT1 pathogenic variations were described in 33 families sharing the same phenotype characterized by an axonal neuropathy with neuromyotonia and autosomal recessive inheritance (NMAN: OMIM #137200). Histidine Triad Nucleotide Binding Protein 1 regulates transcription, cell-cycle control, and is possibly involved in neuropsychiatric pathophysiology. Herein, we report seven French patients with NMAN identified by Next Generation Sequencing. We conducted a literature review and compared phenotypic and genotypic features with our cohort. We identified a new HINT1 pathogenic variation involved in NMAN: c.310G>C p.(Gly104Arg). This cohort is comparable with literature data regarding age of onset (7,4yo), neuronal involvement (sensorimotor 3/7 and motor pure 4/7), and skeletal abnormalities (scoliosis 3/7, feet anomalies 6/7). We expand the phenotypic spectrum of HINT1-related neuropathy by describing neurodevelopmental or psychiatric features in six out of seven individuals such as generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), mood disorder and attention deficit hyperactivity disorder (ADHD). However, only 3/128 previously described patients had neuropsychiatric symptomatology or neurodevelopmental disorder. These features could be part of HINT1-related disease, and we should further study the clinical phenotype of the patients.

A novel mutation in HINT1 gene causes autosomal recessive axonal neuropathy with neuromyotonia, effective treatment with carbamazepine and review of the literature.

INTRODUCTION: Autosomal recessive axonal neuropathy with neuromyotonia (ARAN-NM) is a rare disease entity linked to mutations in the histidine triad nucleotide binding protein 1 (HINT1) gene. The diagnosis and treatment of ARAN-NM are challenging. There have been few reports of ARAN-NM in East Asia. METHODS: A 15-year-old Chinese ARAN-NM patient developed muscle weakness, cramps and atrophy in the lower limbs at the age of 12. Electromyography (EMG) showed motor axonal degeneration and neuromyotonic discharges. Whole exome sequencing was performed. Bioinformatic methods and computational 3D structure modeling were used to analyze the identified variant. According to literature review, carbamazepine was prescribed to the patient. RESULTS: Genetic tests identified a homozygous mutation c.356G > T (p.R119L) in the HINT1 gene, which has never been reported before according to HGMD database. Several bioinformatic approaches predicted the variant was damaging. Computational 3D modeling indicated the variant changed the structure of HINT1 protein. Notably, we demonstrated the positive effects of carbamazepine in treating muscle stiffness and cramps of ARAN-NM. DISCUSSION: 22 variants have been reported in the HINT1 gene, and we identified a novel c.356G > T (p.R119L) variant. Our study expands the genetic spectrum of ARAN-NM. Moreover, large clinical trials are required to further demonstrate the role of carbamazepine in ARAN-NM.

Myasthenia gravis coexisting with HINT1-related motor axonal neuropathy without neuromyotonia: a case report.

BACKGROUND: HINT1 mutations cause an autosomal recessive axonal neuropathy with neuromyotonia. This is a first case report of coexistence of myasthenia gravis (MG) and HINT1-related motor axonal neuropathy without neuromyotonia. CASE PRESENTATION: A 32-year-old woman presented with recurrent ptosis for 8 years, diplopia for 2 years and limb weakness for 1 year and a half. Neostigmine test, elevated AChR antibody level and positive repetitive nerve stimulation supported the diagnosis of MG. Electroneurography (ENG) and electromyography (EMG) examinations revealed a motor axonal neuropathy without neuromyotonic or myokymic discharges. Next-generation sequencing and Sanger sequencing were performed to identify the gene responsible for suspected hereditary neuropathy. Genetic testing for a HINT1 mutation was performed and revealed a homozygous mutation at c.278G>T (p. G93V). The patient was treated with pyridostigmine, oral prednisolone and azathioprine. Her ptosis and diplopia have significantly improved at 6-month follow-up. CONCLUSIONS: Concurrence of MG and hereditary motor axonal neuropathy without neuromyotonia is quite rare. Detection of ptosis with or without ophthalmoplegia, distribution of limb weakness, and reflex can help in recognizing the combination of MG and peripheral neuropathy. Early diagnosis is important for initial treatment and prognosis. The novel homozygous variant c.278G>T(p.G93V) contributes to the pathogenic variants spectrum of the HINT1 gene.

Integrated analysis of ceRNA network reveals potential prognostic Hint1-related lncRNAs involved in hepatocellular carcinoma progression.

BACKGROUND: Hint1 is a novel tumor suppressor gene, and inactivation of its expression is closely associated with the carcinogenesis of a variety of malignancies. The effects of Hint1 deficiency on the competing endogenous RNA (ceRNA) regulatory network in the context of HCC remains to be fully characterized. This study aims to explore Hint1-related hub lncRNAs in HCC and to establish a reliable prognostic model for HCC patients based on these hub lncRNAs. METHODS: lncRNA + mRNA microarray was used to identify differentially expressed (DE) lncRNAs and mRNAs in Huh7 cells before and after Hint1 knockdown. A Hint1-related ceRNA network was mapped by bioinformation technology. The DEmRNAs in the network were analyzed via GO and KEGG enrichment analyses. Hub DElncRNAs associated with HCC patient prognosis were then detected through univariate and multivariate Cox regression analyses and were incorporated into a prognostic model. The prognostic value of this model was then assessed through the use of Kaplan-Meier curves, time-related ROC analyses, and nomograms. We also utilized Kaplan-Meier curves to validate the relationship between hub lncRNAs and the overall survival (OS) of HCC patients. Finally, A Hint1-related core ceRNA network based on the hub DElncRNAs and DEmRNAs was mapped. RESULTS: We identified 417 differentially expressed DElncRNAs and 2096 DEmRNAs in Huh7 cells before and after Hint1 knockdown. Three hub DElncRNAs (LINC00324, SNHG3, and DIO3OS) in the Hint1-associated ceRNA network were screened out using univariate and multivariate Cox regression analyses. A hepatocellular carcinoma (HCC) prognostic risk-scoring model and nomogram were constructed using these three hub lncRNAs, and it was confirmed that the risk score of the model could be used as an independent predictor of HCC prognosis. A Hint1-related core ceRNA network based on the hub DElncRNAs and DEmRNAs was also mapped. CONCLUSION: We constructed a reliable prognostic model for HCC patients based on three Hint1-related hub lncRNAs, and we believe these three hub lncRNAs may play critical roles in hepatocarcinogenesis, and progression.

Intracellular HINT1-Assisted Hydrolysis of Nucleoside 5'-O-Selenophosphate Leads to the Release of Hydrogen Selenide That Exhibits Toxic Effects in Human Cervical Cancer Cells.

In this study, we present a new selenium derivative, 2'-deoxyguanosine-5'-O-selenophosphate (dGMPSe), synthesized by the oxathiaphospholane method and adapted here for the synthesis of nucleoside selenophosphates. Using biochemical assays (HPLC- and fluorescence-based), we investigated the enzymatic activity of HINT1 towards dGMPSe in comparison with the corresponding thiophosphate nucleoside, i.e., dGMPS. Both substrates showed similar kcat and a small difference in Km, and during the reactions the release of reducing agents such as H2Se and H2S were expected and detected. MTT viability assay and microscopic analysis showed that dGMPSe was toxic to HeLa cancer cells, and this cytotoxicity was due to the release of H2Se. The release of H2Se or H2S in the living cells after administration of dGMPSe and/or dGMPS, both without carrier and by electroporation, was observed using a fluorescence assay, as previously for NMPS. In conclusion, our comparative experiments with dGMPSe and dGMPS indicate that the HINT1 enzyme is capable of converting (d)NMPSe to (d)NMP and H2Se, both in vitro and intracellularly. Since the anticancer activity of various selenium compounds depends on the formation of hydrogen selenide, the actual inducer of cell death, we propose that selenium-containing nucleotides represent another option as novel compounds with anticancer therapeutic potential.

HINT1 deficiency in aged mice reduces anxiety-like and depression-like behaviours and enhances cognitive performances.

Histidine triad nucleotide-binding protein 1 (HINT1) is regarded as a haplo-insufficient tumour suppressor and is closely associated with many neuropsychiatric disorders, including major depressive disorders. In addition, HINT1 knockout (KO) mice exhibit anxiolytic-like behaviour, antidepression-like behaviour, and enhanced cognitive performance in several studies. However, it is still unclear whether aging contributes to these changes in the emotion and cognition of HINT1 KO mice. This study examined the role of aging in anxiety-like and depression-like behaviours and cognition behaviours in aged HINT1 KO mice compared with young HINT1 KO mice and their wild-type littermates, along with a number of molecular biological methods. In a battery of behavioural tests, aged wild-type mice showed increased anxiety-like and depression-like behaviours and decreased cognitive performance, along with lower expression levels of glutathione peroxidase, enhanced amount of malondialdehyde, and decreased expression levels of brain-derived neurotrophic factor and tyrosine kinase B in the hippocampus and PFC compared to young wild-type mice. HINT1 KO mice showed reduced anxiety-like and depression-like behaviours and enhanced cognitive performance compared to age-matched wild-type mice. In addition, HINT1 KO mice also showed increased GSH-Px and superoxide dismutase, and decreased malondialdehyde, together with enhanced BDNF and Trk-B expression in the hippocampus and PFC. However, when compared with young HINT1 KO mice, aged HINT1 KO mice did not show increased anxiety-like and depression-like behaviours. And there are no differences in the expression level of superoxide dismutase, malondialdehyde, BDNF, and Trk-B between aged and young HINT1 KO mice. In summary, HINT1 deficiency can counteract age-related emotion and cognition dysfunction.

Comparison of anti-SARS-CoV-2 activity and intracellular metabolism of remdesivir and its parent nucleoside.

Remdesivir, a monophosphate prodrug of nucleoside analog GS-441524, is widely used for the treatment of moderate to severe COVID-19. It has been suggested to use GS-441524 instead of remdesivir in the clinic and in new inhalation formulations. Thus, we compared the anti-SARS-CoV-2 activity of remdesivir and GS-441524 in Vero E6, Vero CCL-81, Calu-3, Caco-2 â€‹cells, and anti-HCoV-OC43 activity in Huh-7 â€‹cells. We also compared the cellular pharmacology of these two compounds in Vero E6, Vero CCL-81, Calu-3, Caco-2, Huh-7, 293T, BHK-21, 3T3 and human airway epithelial (HAE) cells. Overall, remdesivir exhibited greater potency and superior intracellular metabolism than GS-441524 except in Vero E6 and Vero CCL-81 â€‹cells.

The σ1 Receptor and the HINT1 Protein Control α2δ1 Binding to Glutamate NMDA Receptors: Implications in Neuropathic Pain.

Nerve injury produces neuropathic pain through the binding of α2δ1 proteins to glutamate N-methyl-D-aspartate receptors (NMDARs). Notably, mice with a targeted deletion of the sigma 1 receptor (σ1R) gene do not develop neuropathy, whereas mice lacking the histidine triad nucleotide-binding protein 1 (Hint1) gene exhibit exacerbated allodynia. σ1R antagonists more effectively diminish neuropathic pain of spinal origin when administered by intracerebroventricular injection than systemically. Thus, in mice subjected to unilateral sciatic nerve chronic constriction injury (CCI), we studied the participation of σ1Rs and HINT1 proteins in the formation of α2δ1-NMDAR complexes within the supraspinal periaqueductal gray (PAG). We found that δ1 peptides required σ1Rs in order to interact with the NMDAR NR1 variant that contains the cytosolic C1 segment. σ1R antagonists or low calcium levels provoke the dissociation of σ1R-NR1 C1 dimers, while they barely affect the integrity of δ1-σ1R-NR1 C1 trimers. However, HINT1 does remove δ1 peptides from the trimer, thereby facilitating the subsequent dissociation of σ1Rs from NMDARs. In σ1R-/- mice, CCI does not promote the formation of NMDAR-α2δ1 complexes and allodynia does not develop. The levels of α2δ1-σ1R-NMDAR complexes increase in HINT1-/- mice and after inducing CCI, degradation of α2δ1 proteins is observed. Notably, σ1R antagonists but not gabapentinoids alleviate neuropathic pain in these mice. During severe neuropathy, the metabolism of α2δ1 proteins may account for the failure of many patients to respond to gabapentinoids. Therefore, σ1Rs promote and HINT1 proteins hinder the formation α2δ1-NMDAR complexes in the PAG, and hence, the appearance of mechanical allodynia depends on the interplay between these proteins.

HINT1-related neuropathy in Greek patients with Charcot-Marie-Tooth disease.

Autosomal recessive axonal neuropathy with neuromyotonia (ARAN-NM) is a rare hereditary neuropathy within the Charcot-Marie-Tooth disease (CMT) spectrum, linked to mutations in the histidine triad nucleotide-binding protein 1 (HINT1) gene. HINT1-related neuropathy is particularly common in selected populations from Central and Eastern Europe but rare in Western European cohorts. It has not been investigated to date in the Greek population. We presently investigated the frequency of HINT1-neuropathy in a selected cohort of 42 Greek index patients with autosomal recessive or sporadic axonal hereditary neuropathy according to standard molecular genetics procedures. We identified 4 patients with biallelic mutations in HINT1, comprising 9.5% of all cases and 44.4% of cases also displaying neuromyotonia. The c.110G> C (p.Arg37Pro) HINT1 mutation was present in all cases (2 homozygous) and the c.250T> C (p.Cys84Arg) in 2 cases (compound heterozygous). HINT1-related neuropathy patients were characterized by early onset and neuromyotonia. Two patients had noteworthy clinical features, one case developing myoclonic epilepsy and the other displaying "adducted thumbs." We conclude that HINT1-related neuropathy is common in selected Greek patients with hereditary neuropathy within the CMT spectrum, in accordance with some, but not all, European populations.

HINT1 founder mutation causing axonal neuropathy with neuromyotonia in South America: A case report.

BACKGROUND: Recessive loss-of-function mutations in HINT1 are associated with predominantly motor axonal peripheral neuropathy with neuromyotonia. Twenty-four distinct pathogenic variants are reported all over the world, including four confirmed founder variations in Europe and Asia. The majority of patients carry the ancient Slavic founder variant c.110G>C (p.Arg37Pro) that shows a distribution gradient from east to west throughout Europe. METHODS: We report a case of HINT1 neuropathy in South America, identified by massive parallel sequencing of a neuropathy gene panel. To investigate the origin of the variant, we performed haplotyping analysis. RESULTS: A Brazilian adolescent presented with recessive axonal motor neuropathy with asymmetric onset and fasciculations. Neuromyotonia was found on needle electromyography. His parents were not consanguineous and had no European ancestry. The patient carried biallelic pathogenic p.Arg37Pro alterations in the first exon of HINT1. Both alleles were identical by descent and originated from the same ancestral founder allele as reported in Europe. CONCLUSION: Our findings expand the geographic distribution of HINT1 neuropathy to South America, where we describe a recognized founder variant in a Brazilian adolescent with no apparent European ancestry. We confirm the association of the hallmark sign of neuromyotonia with the disease.

Biochemical, crystallographic and biophysical characterization of histidine triad nucleotide-binding protein 2 with different ligands including a non-hydrolyzable analog of Ap4A.

BACKGROUND: Human HINT2 is an important mitochondrial enzyme involved in many processes such as apoptosis and bioenergetics, but its endogenous substrates and the three-dimensional structure of the full-length protein have not been identified yet. METHODS: An HPLC assay was used to test the hydrolytic activity of HINT2 against various adenosine, guanosine, and 2'-deoxyguanosine derivatives containing phosphate bonds of different types and different leaving groups. Data on binding affinity were obtained by microscale thermophoresis (MST). Crystal structures of HINT2, in its apo form and with a dGMP ligand, were resolved to atomic resolution. RESULTS: HINT2 substrate specificity was similar to that of HINT1, but with the major exception of remarkable discrimination against substrates lacking the 2'-hydroxyl group. The biochemical results were consistent with binding affinity measurements. They showed a similar binding strength of AMP and GMP to HINT2, and much weaker binding of dGMP, in contrast to HINT1. A non-hydrolyzable analog of Ap4A (JB419) interacted with both proteins with similar Kd and Ap4A is the signaling molecule that can interact with hHINT1 and regulate the activity of some transcription factors. CONCLUSIONS: Several forms of homo- and heterodimers of different lengths of N-terminally truncated polypeptides resulting from degradation of the full-length protein were described. Ser144 in HINT2 appeared to be functionally equivalent to Ser107 in HINT1 by supporting the protonation of the leaving group in the hydrolytic mechanism of HINT2. SIGNIFICANCE: Our results should be considered in future studies on the natural function of HINT2 and its role in nucleotide prodrug processing.

HINT1 Is Involved in the Chronic Mild Stress Elicited Oxidative Stress and Apoptosis Through the PKC ε/ALDH-2/4HNE Pathway in Prefrontal Cortex of Rats.

Major depressive disorder (MDD) is a severe, highly heterogeneous, and life-threatening psychiatric disease which affects up to 21% of the population worldwide. A new hypothesis suggests that the mitochondrial dysfunction causing oxidative stress (OS) and dysregulation of apoptosis in brain might be one of the key pathophysiological factors in MDD. Histidine triad nucleotide binding protein 1 (HINT1), which was first supposed to be protein kinase C (PKC) inhibitor, has been gradually demonstrated to be involved in diverse neuropsychiatric diseases. It still remains elusive that how HINT1 involves in depression. The present study utilized a rat model exposed to chronic mild stress (CMS) to explore the involvement of HINT1 in depression. Face validity, construct validity and predictive validity of CMS model were comprehensive evaluated in this study. Behavioral tests including sucrose preference test, open field test, and elevated plus maze and forced swimming test revealed that stressed rats displayed elevated level of anxiety and depression compared with the controls. CMS rats showed a significant decrease of superoxide dismutase, and a marked increase malondialdehyde levels in prefrontal cortex (PFC). We also found the CMS rats had elevated expression of HINT1, decreased levels of phosphorylated-PKC ε and aldehyde dehydrogenase-two (ALDH-2), and accumulated 4-hydroxynonenal (4HNE) in PFC. Moreover, CMS increased the levels of cleaved caspase-3 and Bax, and decreased the level of Bcl-2 in PFC. The alterations in behavior and molecule were prevented by antidepressant venlafaxine. These results demonstrated that HINT1 was involved in the CMS elicited OS and apoptosis in PFC, probably through the PKC ε/ALDH-2/4HNE pathway. The results suggest that the suppression of HINT1 might have potential as a novel therapeutic strategy for depression.