Bellad, Anikha

AbstractBackgroundAbnormalities in ataxin‐2 associated with spinocerebellar ataxia type 2 (SCA2) may lead to widespread disruptions in the proteome. This study was performed to identify dysregulated proteome in SCA2 and to explore its clinical‐radiological correlations.MethodsCerebrospinal fluid (CSF) samples from 21 genetically confirmed SCA2 were subjected to shotgun proteome analysis using mass spectrometry (MS) and tandem mass tag (TMT)‐based multiplexing. Proteins with at least 1.5‐fold change in abundance were identified. Their relative abundance was measured using parallel reaction monitoring (PRM) and correlated against disease‐related factors.ResultsEleven proteins were significantly upregulated in SCA2. They belonged to the family of cell adhesion molecules and granins. Their fold changes showed significant clinical, genetic, and radiological correlations.ConclusionsSignificant dysregulation of CSF proteome is seen in SCA2. The dysregulated protein may have potential use in clinical evaluation of patients with SCA2.

AbstractThalassemias are a group of inherited monogenic disorders characterized by defects in the synthesis of one or more of the globin chain subunits of the hemoglobin tetramer. Delta‐beta (δβ‐) thalassemia has large deletions in the β globin gene cluster involving δ‐ and β‐globin genes, leading to absent or reduced synthesis of both δ‐ and β‐globin chains. Here, we used direct globin‐chain analysis using tandem mass spectrometry for the diagnosis of δβ‐thalassemia. Two cases from unrelated families were recruited for the study based on clinical and hematological evaluation. Peptides obtained after trypsin digestion of proteins extracted from red blood cell pellets from two affected individuals and their parents were analyzed using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). Mass spectrometric analysis revealed a severe reduction in δ, β, and Aγ globin proteins with increased Gγ globin protein in the affected individuals. The diagnosis of Gγ(Aγδβ)0 ‐thalassemia in the homozygous state in the affected individuals and in the heterozygous state in the parents was made from our results. The diagnosis was confirmed at the genetic level using multiplex ligation‐dependent probe amplification (MLPA). Our findings demonstrate the utility of direct globin protein quantitation using LC‐MS/MS to quantify individual globin proteins reflecting changes in globin production. This approach can be utilized for accurate and timely diagnosis of hemoglobinopathies, including rare variants, where existing diagnostic methods provide inconclusive results.

For precision in clinical oncology practice, detection of tumor-derived peptides and proteins in urine offers an attractive and noninvasive alternative for diagnostic or screening purposes. In this study, we report comparative quantitative proteomic profiling of urine samples from patients with gastric cancer and healthy controls using tandem mass tags-based multiplexed mass spectrometry approach. We identified 1504 proteins, of which 246 were differentially expressed in gastric cancer cases. Notably, ephrin A1 (EFNA1), pepsinogen A3 (PGA3), sortilin 1 (SORT1), and vitronectin (VTN) were among the upregulated proteins, which are known to play crucial roles in the progression of gastric cancer. We also found other overexpressed proteins, including shisa family member 5 (SHISA5), mucin like 1 (MUCL1), and leukocyte cell derived chemotaxin 2 (LECT2), which had not previously been linked to gastric cancer. Using a novel approach for targeted proteomics, SureQuant, we validated changes in abundance of a subset of proteins discovered in this study. We confirmed the overexpression of vitronectin and sortilin 1 in an independent set of urine samples. Altogether, this study provides molecular candidates for biomarker development in gastric cancer, and the findings also support the promise of urinary proteomics for noninvasive diagnostics and personalized/precision medicine in the oncology clinic.

Shukla-Vernon syndrome (SHUVER) is an extremely rare neurodevelopmental disorder characterized by global developmental delay, intellectual disability, behavioral anomalies, and dysmorphic features. Pathogenic variants in the BCORL1 gene have been identified as the molecular cause for this disorder. The BCORL1 gene encodes for BCL-6 corepressor-like protein 1, a transcriptional corepressor that is an integral component of protein complexes involved in transcription repression. In this study, we report an Indian family with two male siblings with features of Shukla-Vernon syndrome. The patients exhibited global developmental delay, intellectual disability, kyphosis, seizures, and dysmorphic features including bushy prominent eyebrows with synophrys, sharp beaked prominent nose, protuberant lower jaw, squint, and hypoplastic ears with fused ear lobes. No behavioral abnormalities were observed. Whole exome sequencing revealed a novel potentially pathogenic arginine to cysteine substitution (p.Arg1265Cys) in the BCORL1 protein. This is the second report of Shukla-Vernon syndrome with a novel missense variant in the BCORL1 gene. Our study confirms and expands the phenotypes and genotypes described previously for this syndrome and should aid in diagnosis and genetic counselling of patients and their families.