PiT2 is an inorganic phosphate (Pi) transporter whose mutations are linked to primary familial brain calcification (PFBC). PiT2 mainly consists of two ProDom (PD) domains and a large intracellular loop region (loop7). The PD domains are crucial for the Pi transport, but the role of PiT2-loop7 remains unclear. In PFBC patients, mutations in PiT2-loop7 are mainly nonsense or frameshift mutations that probably cause PFBC due to C-PD1131 deletion. To date, six missense mutations have been identified in PiT2-loop7; however, the mechanisms by which these mutations cause PFBC are poorly understood. Here, we found that the p.T390A and p.S434W mutations in PiT2-loop7 decreased the Pi transport activity and cell surface levels of PiT2. Furthermore, we showed that these two mutations attenuated its membrane localization by affecting adenosine monophosphate-activated protein kinase (AMPK)- or protein kinase B (AKT)-mediated PiT2 phosphorylation. In contrast, the p.S121C and p.S601W mutations in the PD domains did not affect PiT2 phosphorylation but rather impaired its substrate-binding abilities. These results suggested that missense mutations in PiT2-loop7 can cause Pi dyshomeostasis by affecting the phosphorylation-regulated cell-surface localization of PiT2. This study helps understand the pathogenesis of PFBC caused by PiT2-loop7 missense mutations and indicates that increasing the phosphorylation levels of PiT2-loop7 could be a promising strategy for developing PFBC therapies.
Humans ; Cell Membrane ; Mutation, Missense ; Phosphates/metabolism* ; Sodium-Phosphate Cotransporter Proteins, Type III/genetics*

OBJECTIVETo investigate the expressions of different forms of ROS fusions in Chinese patients with cholangiocarcinoma (CCA).

METHODSRT-PCR was employed to examine formalin-fixed and paraffin-embedded CCA samples from stage I-IV patients for detection of ROS fusions involving Fused in Glioblastoma (FIG), solute carrier protein (SLC34A2) and major histocompatibility complex class II invariant chain (CD74). Serpin peptidase inhibitor clade A member 1 (SERPINA1) was detected as the reference gene.

RESULTSIn all the 56 CCA samples, 80.4% (45/56) were positive for SERPINA1 expression as evaluable samples. Of these evaluable samples, none expressed the ROS fusions.

CONCLUSIONROS fusions are not common in Chinese CCA patients.

Antigens, Differentiation, B-Lymphocyte ; genetics ; metabolism ; Bile Duct Neoplasms ; metabolism ; pathology ; Carrier Proteins ; genetics ; metabolism ; Cholangiocarcinoma ; metabolism ; pathology ; Female ; Gene Expression ; Histocompatibility Antigens Class II ; genetics ; metabolism ; Humans ; Male ; Membrane Proteins ; genetics ; metabolism ; Middle Aged ; Oncogene Proteins, Fusion ; genetics ; metabolism ; Paraffin Embedding ; Protein-Tyrosine Kinases ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Sodium-Phosphate Cotransporter Proteins, Type IIb ; genetics ; metabolism

Antigens, Differentiation, B-Lymphocyte ; genetics ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; genetics ; metabolism ; Gene Fusion ; Gene Rearrangement ; Histocompatibility Antigens Class II ; genetics ; Humans ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Lung Neoplasms ; drug therapy ; genetics ; metabolism ; Protein Kinase Inhibitors ; therapeutic use ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; genetics ; metabolism ; Proto-Oncogene Proteins ; antagonists & inhibitors ; genetics ; metabolism ; Pyrazoles ; therapeutic use ; Pyridines ; therapeutic use ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; Sodium-Phosphate Cotransporter Proteins, Type IIb ; genetics

OBJECTIVETo describe clinical and genetic feature in a Chinese family with familial idiopathic basal ganglia calcification 3 (IBGC-3) caused by a novel mutation in the SLC20A2 gene.

METHODSClinical data was collected from a family with familial IBGC-3. All of the family members underwent cerebral CT. Potential mutation of the SLC20A2 gene were screened in the proband, 5 symptomatic patients, 5 asymptomatic family members, and 100 healthy Chinese controls. Exon 8 of the SLC20A2 gene was cloned into plasmid and sequenced.

RESULTSThere were 6 symptomatic patients (3 males and 3 females) in an autosomal dominant pedigree. The patients manifested as juvenile-onset paroxysmal kinesigenic dyskinesia, in addition to pyramidal signs in proband. 5 patients alive had calcification in bilateral basal ganglia and subcortical areas. One asymptomatic member also had calcification in the brain; and 2 cases of asymptomatic young members had bilateral globus pallidus calcification. A novel c.1086delC mutation in SLC20A2 gene has been identified in proband and 7 family members with intracranial calcification. The deletion mutation was not found in 2 family members without intracranial calcification and healthy controls members. There is no clear relationship between clinical symptoms and the severity of calcification in cerebral CT.

CONCLUSIONFamilial idiopathic basal ganglia calcification caused by the SLC20A2 gene mutation can manifest as juvenile onset paroxysmal kinesigenic dyskinesia. Further study should be done to validate the unrelated relationships between the severity of calcification in IBGC 3 cranial CT and clinical symptoms.

Adolescent ; Adult ; Basal Ganglia Diseases ; genetics ; Calcinosis ; genetics ; Child ; Female ; Humans ; Male ; Mutation ; Neurodegenerative Diseases ; genetics ; Sodium-Phosphate Cotransporter Proteins, Type III ; genetics ; Tomography, X-Ray Computed

Basal Ganglia ; pathology ; Calcinosis ; complications ; Female ; Humans ; Middle Aged ; Mutation ; Sodium-Phosphate Cotransporter Proteins, Type III ; genetics ; Supranuclear Palsy, Progressive ; etiology

BACKGROUNDHyperphosphatemia in renal failure has been identified as a major role in the pathogenesis of hyperparathyroidism that is independent of changes in serum calcium and 1,25(OH)(2)D(3). The aim of this study was to evaluate the expression of parathyroid Pit-1 in hyperphosphatemia-induced secondary hyperparathyroidism (SHPT) of chronic renal failure (CRF) rats.

METHODSWistar rats with CRF induced by 5/6 nephrectomy were ramdomly fed with diet containing 1.2% inorganic phosphate (Pi, high phosphate (HP) group, n = 9) or 0.2% Pi (low phosphate (LP) group, n = 9) for 10 weeks starting from the fourth week after the surgery. Another 7 nephrectomy rats with HP diet were intraperitoneally injected with phosphonoformic acid (PFA, the specific inhibitor of Pit-1, HP + PFA group) 0.15 g/kg every other day for 10 weeks starting from HP diet. Another 6 HP rats injected with the same amount of normal saline as the control of the HP + PFA group (HP + saline group). At the same time, 9 rats with sham surgery received HP diet as the controls. At the 4th week and 14th week, blood was taken for measurement of serum creatinine (SCr), serum calcium (SCa), serum phosphorus (SPi), 1,25(OH)(2)D(3) and intact parathyroid hormone (iPTH). At the 14th week, two parathroid glands (PTGs) of each rat were removed by microsurgery, one gland for immunohistochemistry analysis of proliferating cell nuclear antigen (PCNA), the other one for detection of Pit-1 by Western blotting, and for the measurement of Pit-1 mRNA and PTH mRNA by real-time quantitative polymerase chain reaction.

RESULTSIn nephrectomy rats, high dierary phosphate induced a marked increase in serum phosphate, iPTH, PTH mRNA and PCNA parathyroid cells, accompanying Pit-1 and its mRNA in parathyroid gland increased significantly. However, serum Ca and 1,25(OH)(2)D(3) remained unchanged. PFA decreased Pit-1 and its mRNA levels to reduce intact PTH, PTH mRNA and PCNA-positive parathyroid cells.

CONCLUSIONSExpression of parathyroid Pit-1 in hyperphosphatemia-induced SHPT of CRF rats was upregulated. Pit-1 may mediate the stimulation to parathyroid gland by hyperphosphatemia.

Animals ; Blotting, Western ; Hyperparathyroidism, Secondary ; etiology ; metabolism ; Hyperphosphatemia ; complications ; Immunohistochemistry ; Kidney Failure, Chronic ; complications ; Male ; Polymerase Chain Reaction ; Rats ; Rats, Wistar ; Sodium-Phosphate Cotransporter Proteins, Type III ; genetics ; metabolism

OBJECTIVEThis study aimed to investigate the susceptibility of mice with streptozotocin(STZ)-induced diabetes mellitus (TIDM) to the uptake of pentavalent inorganic arsenic (iAsV) and the possible molecular mechanism.

METHODSTIDM was induced in mice by STZ. TIDM and normal mice were treated with 15.0 mg/kg Na2HAsO4·12H2O by intragastric administration. Then, the concentrations of arsenic in various tissues were measured by atomic fluorescence spectrometry. The gene expression levels of Pit1 and Pit2 were quantified by real-time RT-PCR, and their protein levels were detected by Western blotting in mouse heart, kidney, and liver tissues.

RESULTSThe concentrations of arsenic in STZ-induced TIDM mouse tissues were higher at 2 h after intragastric administration of Na2HAsO4·12H2O. Compared with the levels in normal mice, PIT1 and PIT2, which play a role in the uptake of iAsV, were upregulated in the livers and hearts of TIDM mice. PIT1 but not PIT2 was higher in TIDM mouse kidneys. The upregulation of Pit1 and Pit2 expression could be reversed by insulin treatment.

CONCLUSIONThe increased uptake of iAsV in TIDM mouse tissues may be associated with increased PIT1 and/or PIT2 expression.

Animals ; Arsenic ; pharmacokinetics ; Diabetes Mellitus, Experimental ; metabolism ; Environmental Pollutants ; pharmacokinetics ; Gene Expression Regulation ; physiology ; Male ; Mice ; Mice, Inbred ICR ; Sodium-Phosphate Cotransporter Proteins, Type III ; genetics ; metabolism ; Transcription Factor Pit-1 ; genetics ; metabolism

BackgroundIdiopathic basal ganglia calcification (IBGC) is a genetic disorder characterized by bilateral basal ganglia calcification and neural degeneration. In this study, we reported a new SLC2OA2 mutation of IBGC and reviewed relevant literature to explore the association between phenotypes and genotypes in Chinese IBGC patients.

MethodsClinical information of the proband and her relatives were collected comprehensively. Blood samples of both the patient and her father were obtained, and genetic screening related to IBGC was performed using second generation sequencing with their consent. Findings were confirmed by Sanger sequencing. Polyphen-2 was used to predict the potential association between mutations and disease. Then, we retrieved literatures of Chinese IBGC patients and explored the association between phenotype and genotype.

ResultsA novel mutation was identified through genetic testing, and it is suggested to be a damage mutation predicted by Polyphen-2. Through literature review, we found that SLC20A2 mutation is the most common cause for IBGC in China. Its hot spot regions are mainly on the 1 and 8 exons; the second common one is PDGFB where the hot spot covered a length of 220-230 bp localized on the 2 exon; moreover, Chinese IBGC patients featured early-onset, more severe movement disorder and relatively mild cognitive impairment compared with those in other countries.

ConclusionsThere is significant heterogeneity both in phenotype and genotype in Chinese IBGC patients. Further research of pathogenic mechanism of IBGC is required to eventually develop precise treatment for individuals who suffered this disease.

Asian Continental Ancestry Group ; Basal Ganglia Diseases ; genetics ; Calcinosis ; genetics ; Exons ; genetics ; Female ; Genetic Association Studies ; Humans ; Male ; Mutation ; genetics ; Neurodegenerative Diseases ; genetics ; Pedigree ; Phenotype ; Sodium-Phosphate Cotransporter Proteins, Type III ; genetics

OBJECTIVETo identify the mutation of solute carrier family 34 member 2 (SLC34A2) gene in a Chinese family with pulmonary alveolar microlithiasis (PAM).

METHODSGenomic DNA was extracted from the family members. DNA sequencing was carried out to confirm the mutation detected by polymerase chain reaction-single strand conformation polymorphisms (PCR-SSCP). The fragments with variation were screened in 100 healthy controls by PCR-SSCP.

RESULTSIn both patients of the family, a homozygous mutation of the SLC34A2 gene was identified in exon 8 (c.A910T), resulting in a premature stop codon. In addition, a homozygous single nucleotide polymorphism (SNP) was found in intron 2 in both patients and the daughter of proband.

CONCLUSIONA novel homozygous mutation in SLC34A2 gene, leading to a premature stop codon therefore a truncated protein, was probably responsible for the PAM in this family. The SNP in intron 2 needs further study.

Adult ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Case-Control Studies ; Exons ; Female ; Humans ; Lung Diseases ; genetics ; Molecular Sequence Data ; Mutation ; Pedigree ; Sodium-Phosphate Cotransporter Proteins, Type IIb ; genetics

OBJECTIVETo investigate the correlation between polymorphisms of uric acid transporter related gene SLC17A1 and hyperuricemia (HUA) among ethnic Uygur patients from Xinjiang.

METHODSA case-control study was carried out, which enrolled 1036 patients with hyperuricemia and 1031 healthy controls. Two single nucleotide polymorphisms (SNPs) of the SLC17A1 gene were determined with Sequenom MassARRAY. Crossover analysis was used to assess the effect of interaction between above SNPs and alcohol drinking on uric acid level.

RESULTSGenotypic and allelic frequencies of the SLC17A1 gene at the two loci in the two groups were compared. The CT genotype of the rs9467596 locus and TC genotype of the rs2096386 locus showed a higher risk for hyperuricemia (OR=1.334, 95%CI:1.082-1.644; OR=1.242, 95%CI:1.015-1.519, respectively). Crossover analysis also revealed that the SLC17A1 rs2096386 polymorphism has a positive interaction with alcohol drinking in a multiplication model (ORint=1.21, P<0.05, OR>1).

CONCLUSIONSNP rs9467596 and rs2096386 of the SLC17A1 gene may have a correlation between hyperuricemia and alcohol drinking among Uygur patients.

Adult ; Aged ; Alcohol Drinking ; ethnology ; genetics ; Alleles ; Asian Continental Ancestry Group ; genetics ; China ; Ethnic Groups ; genetics ; Female ; Gene Frequency ; Genetic Predisposition to Disease ; ethnology ; genetics ; Genotype ; Humans ; Hyperuricemia ; ethnology ; genetics ; Male ; Middle Aged ; Odds Ratio ; Polymorphism, Single Nucleotide ; Risk Factors ; Sodium-Phosphate Cotransporter Proteins, Type I ; genetics ; Young Adult