OBJECTIVE: To analyze the clinical characteristics and genetic etiology of a child with Christianson syndrome (CS). METHODS: A 1-year-and-5-month-old boy with CS diagnosed at the First Affiliated Hospital of Zhengzhou University in April 2021 was selected as the study subject. Clinical data were retrospectively analyzed. Peripheral blood samples were obtained from the child and his parents, followed by genomic DNA extraction and whole exome sequencing (WES). Candidate variant was validated by Sanger sequencing. This study has been approved by the Medical Ethics Committee of the Hospital of Zhengzhou University (Ethics No. 2024-KY-1103-001). RESULTS: The child has manifested with seizures, microcephaly, and global developmental delay. WES revealed that he has harbored a novel de novo hemizygous nonsense variant of the SLC9A6 gene, namely c.1014G>A (p.W338*). Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as pathogenic. CONCLUSION The hemizygous c.1014G>A nonsense variant of the SLC9A6 gene probably underlay the pathogenesis in this child. Above discovery has expanded mutational spectrum of the SLC9A6 gene and enabled definite diagnosis of the child.
Humans ; Male ; Infant ; Microcephaly/genetics* ; Spasms, Infantile/genetics* ; Sodium-Hydrogen Exchangers/genetics* ; Exome Sequencing ; Intellectual Disability/genetics* ; Genetic Diseases, X-Linked/genetics* ; Mutation ; Seizures/genetics* ; Ataxia ; Epilepsy ; Ocular Motility Disorders

OBJECTIVE: To evaluate the clinical significance of a hemizygous c.1042-10G>C variant of the SLC9A7 gene NM_001257291.2) previously identified in individuals with neurodevelopmental disorders, and to provide an evidence-based guidance for prenatal genetic counseling. METHODS: Four families presented at the Medical Genetics Center of Henan Provincial People's Hospital between December 2022 and July 2024 were included in this study. Phenotypic information and biological samples were collected from family members. Genomic DNA was extracted and subjected to whole-exome sequencing and copy number variation analysis to identify candidate pathogenic variants. Sanger sequencing was performed for familial co-segregation analysis. Reverse-transcription PCR was used to assess the RNA splicing pattern of the variant in peripheral blood samples. Quantitative PCR was employed to analyze the expression profiles of various SLC9A7 transcripts in fetal brain tissue and peripheral blood samples. Pathogenicity of the variant was classified based on guidelines from the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of Henan Provincial People's Hospital (Ethics No.: 2021-171). RESULTS: Six hemizygous males carrying the SLC9A7 c.1042-10G>C variant were identified among the four families, which included three adult males and two male infants with normal phenotypes. Only one affected male from family 3 exhibited global developmental delay, short neck, webbed neck, ocular dysplasia, and congenital corneal leukoma. He also had a history of perinatal asphyxia and carried an additional hemizygous variant HUWE1 c.12283C>G. Reverse-transcription PCR showed no aberrant splicing in heterozygous or hemizygous carriers compared to healthy controls, suggesting that the variant does not affect RNA splicing. Quantitative PCR revealed that NM_001257291.2 is the predominant transcript expressed in fetal brain tissue and peripheral blood. CONCLUSION The SLC9A7 c.1042-10G>C variant does not alter RNA splicing and is present in multiple phenotypically normal males, which supported its classification as a benign variant.
Humans ; Male ; Female ; Genetic Counseling ; Pedigree ; Adult ; DNA Copy Number Variations/genetics* ; Sodium-Hydrogen Exchangers/genetics* ; Exome Sequencing

Animals ; Autophagy/genetics* ; Cholesterol/metabolism* ; Gene Expression Regulation ; Integrases/metabolism* ; Leydig Cells/metabolism* ; Male ; Mice, Knockout ; Multienzyme Complexes/metabolism* ; Phosphoproteins/metabolism* ; Primary Cell Culture ; Progesterone Reductase/metabolism* ; RNA Splicing Factors/metabolism* ; Scavenger Receptors, Class B/metabolism* ; Sequestosome-1 Protein/metabolism* ; Signal Transduction ; Sirtuin 1/genetics* ; Sodium-Hydrogen Exchangers/metabolism* ; Steroid 17-alpha-Hydroxylase/metabolism* ; Steroid Isomerases/metabolism* ; Testosterone/genetics*

Important progress has been made in the interpretation of subcellular location, ion transport characteristics and biological functions of endosomal Na⁺,K⁺/H⁺ antiporter in Arabidopsis thaliana. The endosomal Na⁺,K⁺/H⁺ antiporter contain two members, AtNHX5 and AtNHX6, whose amino acid sequence similarity is 78.7%. Studies have shown that AtNHX5 and AtNHX6 are functionally redundant, and they are all located in Golgi, trans-Golgi network (TGN), endoplasmic reticulum (ER) and prevacuolar compartment (PVC). AtNHX5 and AtNHX6 are critical for salt tolerance stress and the homeostasis of pH and K⁺. It has been reported that there are conservative acidic amino acid residues that can regulate their ion activity in the endosomal NHXs transmembrane domain, which plays a decisive role in their own functions. The results of the latest research indicate that endosomal NHXs affect vacuolar transport and protein storage, and participate in the growth of auxin-mediated development in A. thaliana. In this paper, the progress of subcellular localization, ion transport, function and application of endosomal NHXs in A. thaliana was summarized.
Arabidopsis ; Arabidopsis Proteins ; Endosomes ; Sodium-Hydrogen Exchangers ; Vacuoles

BACKGROUNDRecent studies showed the central Na+/H+ exchanger type 3 (NHE3) has a close relationship with ventilation control. The objective of the study is to investigate the role of NHE3 in sleep apnea in Sprague-Dawley (SD) rats.

METHODSA sleep study was performed on 20 male SD rats to analyze the correlation between the sleep apneic events and total NHE3 protein content and inactive NHE3(pS552) in the brainstem measured by Western blotting. Another 20 adult male SD rats received 3 days of sleep and respiration monitoring for 6 hours a day, with adaption on the first day, 0.5% DMSO microinjection into the fourth ventricle on the second day, and AVE0657 (specific inhibitor of NHE3) microinjection on the third day. Rats were divided into two groups with injection of 5 µmol/L or 8 µmol/L AVE0657 before the sleep study. The effects of AVE0657 on sleep apnea and sleep structure of rats were analyzed through self-control.

RESULTSThe total post-sigh apnea index (TPSAI) and post-sigh apnea index in non-rapid eye movement (NREM) sleep (NPSAI) and total apnea index (AI) in NREM sleep (NAI) were negatively correlated with NHE3(pS552) protein contents in the brainstem (r = -0.534, -0.547 and -0.505, respectively, P < 0.05). The spontaneous apnea index in REM sleep (RSPAI) was positively correlated with the level of NHE3(pS552) protein expression in the brainstem (r = 0.556, P < 0.05). However, the sleep AI had no relationship with total NHE3 protein. Compared with the blank control and microinjection of 0.5% DMSO, 5 µmol/L AVE0657 significantly reduced the total AI and NPSAI (both P < 0.05) without a significant effect on sleep architecture. In contrast to blank control and microinjection of 0.5% DMSO, injection of 8 µmol/L AVE0657 significantly reduced the AI and PSAI in NREM and REM sleep (all P < 0.05).

CONCLUSIONSThe severity of sleep apnea was negatively correlated with central inactive NHE3. A specific inhibitor of NHE3 decreased the sleep AI. Thus, our results indicate that central NHE3 might be a molecular target for sleep apnea treatment, whose inhibitors may be potential therapeutic drugs for sleep apnea.

Animals ; Male ; Rats ; Rats, Sprague-Dawley ; Sleep Apnea Syndromes ; metabolism ; physiopathology ; Sleep, REM ; physiology ; Sodium-Hydrogen Exchanger 3 ; Sodium-Hydrogen Exchangers ; antagonists & inhibitors ; metabolism

HCO3(-) reabsorption in the renal tubules plays a critically important role in maintaining the global acid-base balance. Loss of HCO3(-) causes metabolic acidosis. Proximal renal tubule is the major site for HCO3(-) reabsorption, accounting for more than 80% of total HCO3(-) reabsorption along the nephron. Over the past more than half centuries, tremendous progresses have been made on understanding the molecular mechanisms underlying the HCO3(-) reabsorption in proximal tubules. The transepithelial movement of HCO3(-) involves the coordinated operation of machineries on both the apical and the basolateral membranes of the epithelial cells. On the apical domain, Na(+)-H(+) exchanger NHE3 and the vacuolar H(+)-ATPase are two major pathways mediating the apical uptake of HCO3(-)-related species. Taken together, NHE3 and H(+)-ATPase are responsible for about 80% of HCO3(-) reabsorption in the proximal tubule. The remaining 20% is likely mediated by pathways yet to be characterized. On the basolateral membrane, NBCe1 represents the only major known pathway mediating the extrusion of HCO3(-) coupled with Na(+) into the interstitial space. In the present article, we provide a historical view about the studies on the mechanisms of HCO3(-) reabsorption since 1940s. Moreover, we summarize the latest progresses emerging over the past decade in the physiological as well as pathological roles of acid-base transporters underlying the HCO3(-) reabsorption in proximal tubules.
Acidosis ; physiopathology ; Animals ; Bicarbonates ; metabolism ; Humans ; Kidney Tubules, Proximal ; physiopathology ; Sodium-Hydrogen Exchangers ; physiology ; Vacuolar Proton-Translocating ATPases ; physiology

This study was purposed to explore the changes of possible angiogenetic factors other than VEGF after inhibition of NHE1 and their related mechanisms. The K562 cells were treated by NHE1 specific inhibitor cariporide, the angiogenesis factors after inhibition of NHE1 were screened by using protein chip, the IL-8 expression level after cariporide treatment was detected by real-time quantitative PCR; the K562 cells with stable interference of NHE1 were constructed, the IL-8 expression level after interference of NHE1 was detected by real-time quantitative PCR; the p38 phosphorylation level in K562 cells treated with cariporide was detected by Western blot. After treatment of K562 cells with p38 inhibitor SB203580, the IL-8 expression level was decreased by real-time quantitative PCR. The results of protein chip showed that IL-8 expression decreased after cariporide treatment. Real-time quantitative PCR confirmed this inhibitory effect. The p38 phosphorylation level increased after cariporide treatment. The down-regulation of IL-8 expression induced by cariporide treatment was partially restored after K562 cells were treated with p38 inhibitor SB203580. It is concluded that the inhibition of NHE1 can inhibit IL-8 expression through up-regulation of p38 phosphorylation.
Cation Transport Proteins ; antagonists & inhibitors ; Down-Regulation ; Guanidines ; pharmacology ; Humans ; Imidazoles ; pharmacology ; Interleukin-8 ; metabolism ; K562 Cells ; Phosphorylation ; drug effects ; Pyridines ; pharmacology ; Sodium-Hydrogen Exchanger 1 ; Sodium-Hydrogen Exchangers ; antagonists & inhibitors ; Sulfones ; pharmacology ; p38 Mitogen-Activated Protein Kinases ; metabolism

Abstract:Subgroup J avian leukosis virus (ALV-J) infect cells by binding to the chNHE1 receptor protein of the host and causes tumors. The tumor incidence of the ALV-J-infected chickens was observed by histo pathology, and virus was isolated on DF-1 cell line. The ALV-J load and mRNA of chNHElreceptor protein were detected by real time PCR. The relationship between ALV-J load, chNHE1 receptor expression levels and tumor spectrum was analyzed. The results showed that the tumors induced by ALV-J in laying hens and local lines of chicken were different. No significant relationship was observed between ALV-J load and tumor spectrum. ALV-J load was positively correlated with mRNA expression of chNHE1. The mRNA expression of chNHE1 increased when the tumors occurred. Our results suggest the chNHE1 protein is not only the receptor of ALV-J infected host but also play an important role in the process of tumor development. This study provides a scientific basis for further studying of oncogenic mechanism of ALV-J.
Animals ; Avian Leukosis ; genetics ; metabolism ; virology ; Avian Leukosis Virus ; genetics ; physiology ; Chickens ; genetics ; metabolism ; Poultry Diseases ; genetics ; metabolism ; virology ; Receptors, Virus ; genetics ; metabolism ; Sodium-Hydrogen Exchangers ; genetics ; metabolism ; Viral Load

This study was aimed to investigate whether the inhibition of NHE1 activity and intracellular acidification can reverse resistance of leukemia cells to the imatinib and to explore downstream signal molecule networks of BCR/ABL in the cells of chronic myelocytic leukemia (CML) patients. The mRNA and protein expression of P-glycoprotein (Pgp) and the drug accumulation were assayed after acidifying the primary leukemia cells of patients or K562/DOX and K562/G01 cells. The effects of intracellular acidification of primary leukemia cells on the phosphorylation level changes of ERK1/2 and p38 MAPK were analyzed by Western blot. The results showed that the intracellular concentration of drugs in the advanced patients increased and the sensitivity of K562/DOX and K562/G01 cells to imatinib was enhanced after intracellular acidification or treatment with NHE1 inhibitor cariporide. With downregulation of intracellular pH, the phosphorylation of p38 MAPK decreased in advanced patients and the phosphorylation of ERK1/2 increased within 3 min and then decreased after 30 min. SB203580, the specific inhibitor of p38 MAPK, displayed a synergistic effect with the inhibitor of NHE1 to downregulate the mRNA and protein expression of Pgp. It is concluded that the inhibiton of NHE1 can significantly decrease the protein expression of Pgp in K562/DOX and K562/G01 cells, increase the accumulation of Rhodamine123 and doxorubicin in the cells of advanced patients and enhance the sensitivity of cells to imatinib in which the p38 MAPK signal transduction pathways involves.
ATP-Binding Cassette, Sub-Family B, Member 1 ; metabolism ; Benzamides ; pharmacology ; Cation Transport Proteins ; antagonists & inhibitors ; metabolism ; Drug Resistance, Neoplasm ; drug effects ; Enzyme Inhibitors ; pharmacology ; Gene Expression Regulation, Leukemic ; Humans ; Imatinib Mesylate ; Imidazoles ; pharmacology ; K562 Cells ; MAP Kinase Signaling System ; Piperazines ; pharmacology ; Pyridines ; pharmacology ; Pyrimidines ; pharmacology ; Sodium-Hydrogen Exchanger 1 ; Sodium-Hydrogen Exchangers ; antagonists & inhibitors ; metabolism ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; metabolism

OBJECTIVETo investigate the effect of adenosine and its agonist on hypoxia-induced right ventricular hypertrophy (RVH) and explore the underlying mechanism.

METHODSFifty-six rats were randomly divided into normoxia group, hypoxia group, and treated hypoxia groups (with different treatments with adenosine, A1 receptor agonist CPA, A2 receptor agonist NECA, CPA plus A1 receptor inhibitor DPCPX, or NECA plus A2B receptor inhibitor MRS1754). The rats except for those in normoxia group were exposed to normobaric chronic hypoxia (9.5%-10.5% oxygen) for 21 days, and the corresponding treatments were administered since the 7th day of hypoxia till day 21 via implantable capsule with a pressure pump. After the treatments, the right ventricles were then removed and weighed for evaluation of hypertrophy, and the expressions of NHE-1 and CnAβ mRNA in the myocardial tissue were detected using RT-PCR.

RESULTSAfter a 21-day hypoxia, the rats showed significantly increased RV/(LV+S) ratio (0.369∓0.033) and RV/BW ratio (0.75∓0.095) compared to those in normoxia group (0.271∓0.010 and 0.59∓0.039, respectively; P<0.001), adenosine treatment group (0.281∓0.022 and 0.65∓0.077, respectively; P<0.001, P=0.025), hypoxia with CPA group (0.313∓0.021 and 0.66∓0.067, respectively P<0.001), and hypoxia with NECA group(0.333∓0.019, and 0.68∓0.074, respectively P<0.001). The NHE-1 and CnAβ mRNA levels in hypoxia group were significantly higher than those in normoxia group, adenosine treatment group, hypoxia with CPA group, and hypoxia with NECA group(P<0.001).

CONCLUSIONAdenosine and its agonist can inhibit hypoxia-induced RVH in rats through the NHE-1/CaN signal pathway.

Adenosine ; agonists ; pharmacology ; Animals ; Hypertrophy, Right Ventricular ; metabolism ; Hypoxia ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; drug effects ; Sodium-Hydrogen Exchangers ; metabolism