PCYT1A deficiency disturbs fatty acid metabolism and induces ferroptosis in the mouse retina.

BACKGROUND: Inherited retinal dystrophies (IRDs) are a group of debilitating visual disorders characterized by the progressive degeneration of photoreceptors, which ultimately lead to blindness. Among the causes of this condition, mutations in the PCYT1A gene, which encodes the rate-limiting enzyme responsible for phosphatidylcholine (PC) de novo synthesis via the Kennedy pathway, have been identified. However, the precise mechanisms underlying the association between PCYT1A mutations and IRDs remain unclear. To address this knowledge gap, we focused on elucidating the functions of PCYT1A in the retina. RESULTS: We found that PCYT1A is highly expressed in Müller glial (MG) cells in the inner nuclear layer (INL) of the retina. Subsequently, we generated a retina-specific knockout mouse model in which the Pcyt1a gene was targeted (Pcyt1a-RKO or RKO mice) to investigate the molecular mechanisms underlying IRDs caused by PCYT1A mutations. Our findings revealed that the deletion of Pcyt1a resulted in retinal degenerative phenotypes, including reduced scotopic electroretinogram (ERG) responses and progressive degeneration of photoreceptor cells, accompanied by loss of cells in the INL. Furthermore, through proteomic and bioinformatic analyses, we identified dysregulated retinal fatty acid metabolism and activation of the ferroptosis signalling pathway in RKO mice. Importantly, we found that PCYT1A deficiency did not lead to an overall reduction in PC synthesis within the retina. Instead, this deficiency appeared to disrupt free fatty acid metabolism and ultimately trigger ferroptosis. CONCLUSIONS: This study reveals a novel mechanism by which mutations in PCYT1A contribute to the development of IRDs, shedding light on the interplay between fatty acid metabolism and retinal degenerative diseases, and provides new insights into the treatment of IRDs.

Factors influencing platelet isolation: a prospective multicenter study from Western China.

Tumor-educated platelets (TEPs) have been widely reported to have promising application potential; nonetheless, platelet isolation from peripheral blood is an important but neglected step in TEPs research for platelet-based liquid biopsy. In this article, we discussed some common influence factors for platelet isolation. To investigate the factors involved in platelet isolation, a prospective multicenter study was conducted on healthy Han Chinese adults (18 to 79 years of age). A total of 208 individuals were included in the final statistical analysis out of the 226 healthy volunteers who were prospectively enrolled from four hospitals. The primary study metric was the platelet recovery rate (PRR). The similar pattern was observed in the four hospitals, The PRR at room temperature (23°C±2°C) was slightly higher than the PRR at cold temperature (4°C±2°C). Moreover, the PRR gradually decreased as the storage time increased. The PRR for samples within 2 hours of storage is significantly higher than for samples beyond 2 hours (p < .05). Additionally, PRR was also affected by the equipment used in different centers. This study confirmed several factors that influence platelet isolation. In our study, we indicated that platelet isolation should be performed within two hours of peripheral blood draw and held at room temperature until isolation, and that centrifuge models should be fixed during the extraction process, which will further improve the research progress of platelet-based liquid biopsy in cancer.

What is the context? Globally, cancer is one of the leading cause of premature death. Early screening is important for cancer diagnosis and treatment and can even significantly lower cancer mortalityGlobally, cancer is one of the leading cause of premature death. Early screening is important for cancer diagnosis and treatment and can even significantly lower cancer mortalityFor the liquid biopsy, isolation is an important step. Early studies have explored the influencing factors of exosome, circulating tumor cells (CTCs), and other components extraction in liquid biopsy.Despite platelet also being an excellent source of liquid biopsy, few studies have explored the factors that influence platelet isolation.Considering the importance of platelet isolation in tumor-based platelet liquid biopsy, our aim is to optimize platelet isolation conditions as much as possible to obtain a high platelet recovery rate.What is new? In this study, we conducted a prospective multicenter study ofhealthy adults from four centers, combining whole blood with platelet-richplasma to investigate factors influencing platelet recovery rate (PRR) during platelet isolation.In our study, we indicated that platelet isolation should be performed within two hours at room temperature, and that centrifuge models should be fixed during the extraction process, which will further improve the research progress of platelet-based liquid biopsy in cancer.What is the impact? In future platelet-related studies, we should fix the sample storage temperature, storage time and centrifuge model in the process of platelet extraction, so as to reduce the variables affecting platelet extraction as much as possible and ensure the stable recovery rate of platelet extraction.

Association between hOGG1 polymorphism rs1052133 and gastric cancer.

PURPOSE: To conduct a comprehensive evaluation of the association of the human8-oxoguanine glycosylase 1 (hOGG1) gene polymorphism rs1052133 with gastric cancer (GC) through a systematic review and meta-analysis of genetic association study. RESULTS: A total of 15 articles from published papers were included in our analysis. The meta-analyses for hOGG1 rs1052133, composed of 4024GC patients and 6022controls, showed low heterogeneity for the included populations in all the genetic models, except for the Caucasian population under allelic genetic model, the Asian population under addictive model and Caucasian population under dominant model. The analyses of all the genetic models in overall pooled populations did not identify any significant association between GC and hOGG1 rs1052133 (Allelic model: C vs. G , p = 0.746; Addictive model: CC vs. GG, p = 0.888; Recessive model: CC +GC vs. GG, p = 0.628; Dominant model: CC vs. GG+GC, p = 0.147), even though stratified analyses were conducted in different ethnicities under each genetic model. MATERIALS AND METHODS: All case-control association studies on hOGG1 and GC reported up to December 15, 2016 in PubMed, Embase, Web of Science, and the Chinese Biomedical Database were retrieved. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for single-nucleotide polymorphism (SNP) using fixed- and random- effects models according to between-study heterogeneity. Publication bias analyses were conducted using Begg test. CONCLUSIONS: This meta-analysis showed there was no association between hOGG1 rs1052133 and GC. Given the limited sample size, further investigations including more ethnic groups are required to validate the association.

Association of IGF1 polymorphism rs6214 with high myopia: A systematic review and meta-analysis.

PURPOSE: To conduct a comprehensive evaluation of the association of Insulin-like growth factor 1 (IGF1) polymorphism rs6214 with high myopia through a systematic review and meta-analysis of candidate genetic association study. METHODS: All case-control association studies on IGF1 and high myopia reported up to 15 June 2016 in PubMed, Embase, Web of Science, and the Chinese Biomedical Database were retrieved. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for single-nucleotide polymorphism (SNP) using fixed and random effects models according to between study heterogeneity. Publication bias analyses were conducted using Begg's test. RESULTS: A total of eight studies from published articles were included in our analysis. The meta-analyses for IGF1 rs6214, composed of 4242 high myopia patients and 4430 controls, showed low heterogeneity for the included populations in all the genetic models, except that of the allelic genetic model in the pooled populations. The analyses of all the genetic models in Chinese, Japanese, and overall pooled populations did not identify any significant association between high myopia and IGF1 rs6214. CONCLUSIONS: This meta-analysis showed there was no association detected between IGF1 rs6214 and high myopia. Given the limited sample size, further investigations including more ethnic groups are required to validate the association.

Novel Compound Heterozygous CBS Mutations Cause Homocystinuria in a Han Chinese Family.

The cystathionine ß-synthase (CBS) gene has been shown to be related to homocystinuria. This study was aimed to detect the mutations in CBS in a Han Chinese family with homocystinuria. A four-generation family from Shandong Province of China was recruited in this study. All available members of the family underwent comprehensive medical examinations. Genomic DNA was collected from peripheral blood of all the participants. The coding sequence of CBS was amplified by polymerase chain reaction (PCR), followed by direct DNA sequencing. Among all the family members, three affected individuals showed typical clinical features of homocystinuria. Two novel compound heterozygous mutations in the CBS gene, c.407T > C (p. L136P) and c.473C > T (p.A158V), were identified by sequencing analysis in this family. Both of the two missense mutations were detected in the three patients. Other available normal individuals, including the patients' parents, grand parents, her younger sister and brother in this family either carried one of the two mutations, or none. In addition, the two mutations were not found in 600 ethnically matched normal controls. This study provides a mutation spectrum of CBS resulting in homocystinuriain a Chinese population, which may shed light on the molecular pathogenesis and clinical diagnosis of CBS-associated homocystinuria.

[Association between LOXL1 gene polymorphisms and primary open angle glaucoma in Sichuan population].

OBJECTIVE: To investigate association between the lysyl oxidase-like 1 (LOXL1) gene single nucleotide polymorphism (SNP) and primary open-angle glaucoma (POAG) in Sichuan population. METHODS: In this study,416 subjects with primary open-angle glaucoma and 997 normal controls were recruited.Three reported LOXL1 tag SNPs (rs1048661,rs3825942 and rs2165241) were genotyped by SNaPshot method. RESULTS: The study showed that the genotypes of LOXL1 rs1048661,rs3825942 and rs2165241 between POAG and control groups were not statistically significant (OR=1.085, 95%CI 0.92-1.28, P=0.578 for rs1048661; OR=1.059, 95%CI 0.82-1.37, P=0.846 for rs3825942; OR=1.006, 95%CI 0.77-1.32, P=0.966 for rs2165241, respectively). There were no significant difference in allele frequency distribution of LOXL1 rs1048661、rs3825942 and rs2165241 between POAG and normal controls (P=0.322, P=0.660, P=0.965). CONCLUSION: The results from the present study do not indicate the association of LOXL1 SNPs (rs1048661, rs3825942 and rs2165241) with POAG in Sichuan population.

[Analysis of COL9A2 gene mutations in a Chinese Han population with pathological myopia].

OBJECTIVE: To analyze the mutation of COL9A2 gene and investigate the molecular pathogenesis of pathological myopia in a Han Chinese population. METHODS: Mutation in the coding region of the COL9A2 gene was screened by Sanger sequencing in 200 subjects with pathological myopia and 200 normal controls. The detected variants were genotyped by SNaPshot method in another 200 myopic cases and 200 normal controls. RESULTS: Sanger sequencing has failed to detect the reported D281fs frameshift mutation in the 200 cases. A novel variant, c.143G>C heterozygous missense mutation in exon 2, was identified in a myopic subject, and another novel variant, c.884G>A heterozygous missense mutation in exon 17, was found in another case. Neither was found in normal controls. One SNP (rs2228564) was detected in the coding region of the COL9A2 gene, but there was no significant difference in its allelic frequencies between the two groups (P> 0.05). Genotyping of the remainder 200 cases and 200 controls by SNaPshot method has found a c.143G>C in 1 case and c.884G>A in 2 cases, though no significant difference between the two groups was detected (P> 0.05). CONCLUSION: The D281fs frameshift mutation in the COL9A2 gene is not associated with pathological myopia in the studied Han Chinese population. Two novel mutations, c.143G>C in exon 2 and c.884G>A in exon 17 of the COL9A2 gene, may contribute to the development of pathological myopia.

[Analysis and carrier screening for copy numbers of SMN and NAIP genes in children with spinal muscular atrophy].

OBJECTIVE: To assess the association of copy number variations of SMN1, SMN2, NAIP, GTF2H2 and H4F5 genes with clinical classification of spinal muscular atrophy in children, and determine the copy number of the SMN gene among pregnant women. A carrier screening was also performed in Sichuan province. METHODS: The copy number variations of the above genes among 53 confirmed SMA patients were determined with MLPA technique. The copy number variations were analyzed by the Fisher's exact test. Deletion of exon 7 in the SMN1 gene was screened with denaturing high performance liquid chromatography (DHPLC) for 427 pregnant women. RESULTS: Among the 53 cases of type I, II, and III SMA patients, the rate of homozygous deletion of both exons 7 and 8 of the SMN1 gene were 100%, 94.44% and 87.50%, respectively, whereas those of homozygous deletion of exon 7 of SMN1 gene were 0, 5.56%, and 12.50%, respectively. The patients with 1, 2, 3, and 4 copies of exon 7 of the SMN2 gene were 11.32%, 67.92%, 13.21% and 7.55%, respectively. The patients with 0, 1, and 2 copies of exon 5 of NAIP gene were 11.32%, 62.26%, and 26.42%, respectively. No deletion was detected in GTF2H2 or H4F5 genes. The heterozygous loss rate of exon 7 in SMN gene in the pregnant women population of Sichuan region was approximately 2.11%. CONCLUSION: Copy number variations of SMN2 and NAIP genes in patients are related to SMA clinical types (P < 0.05). In contrast, there was no relationship between SMA clinical types and deletion of exons 7 and 8 in the SMN1 gene (P > 0.05). Analysis of copy number change in SMN1 gene can assist SMA carrier screening. However, when the general population without SMA family history is screened for disease-causing genes, it should be noted that the type "2+0" carriers may affect the screening result, and the result should be interpreted with caution.

Evaluation of MMP2 as a candidate gene for high myopia.

PURPOSE: Matrix metalloproteinase 2 (MMP2) has been shown to be expressed in the human sclera, and is increased in the sclera of the eye with myopia induced by form deprivation in chicks when compared with the control eye. The purpose of this study was to examine the relationship between high myopia and MMP2 in a mainland Han Chinese population. METHODS: Four hundred unrelated patients with high myopia and 400 normal controls in a mainland Han Chinese population were studied. All the subjects were genotyped for 20 tag single nucleotide polymorphisms (SNPs) in MMP2 with the dye terminator-based SNaPshot method. The distribution of the genotypes in the cases and controls was compared with a χ(2) test. Screening for mutations in the coding regions and the adjacent intronic regions of MMP2 was performed in 200 patients with high myopia and 200 normal controls by direct sequencing. RESULTS: None of the 20 tested SNPs showed significant association with high myopia in this study. Seven variations were detected upon sequencing of the coding regions and the adjacent intronic regions of MMP2 in 200 subjects with high myopia and 200 normal controls. One novel variation, c.1287G>A (p.K429K), was detected in 79 of the 200 patients with high myopia (65 heterozygous and 14 homozygous) and in 84 of the 200 controls (67 heterozygous and 17 homozygous). The c.1810G>A mutation (p. Arg500His) was detected in three of the 200 patients with high myopia but not in the controls. The five other variations, known as polymorphisms, were detected in the case and control groups. CONCLUSIONS: We found no evidence that MMP2 is responsible for high myopia in these Han Chinese subjects and hence is unlikely to be important in the genetic predisposition to high myopia. Our results imply that MMP2 may not play a major role in high myopia in the Han Chinese population.