Population-based comparative analysis of differentially expressed genes between Kashin–Beck disease grades I and II

The Importance of Se-Related Genes in the Chondrocyte of Kashin-Beck Disease Revealed by Whole Genomic Microarray and Network Analysis

Kashin-Beck disease (KBD) is an endemic, chronic, and degenerative osteoarthropathy. Selenium (Se) deficiency plays important role in the pathogenesis of KBD. We aimed to screen Se-related gene from chondrocytes of patients with KBD. Whole-genome oligonucleotide microarrays were used to detect differentially expressed genes. qRT-PCR was used to confirm the microarray results. Comparative Toxicogenomics Database (CTD) was used to screen Se-related genes from differentially expressed genes. Gene Ontology (GO) classifications and network analysis of Se-related genes were constituted by STRING online system. Three hundred ninety-nine differentially expressed genes were obtained from microarray. Among them, 54 Se-related genes were identified by CTD. The qRT-PCR validation showed that four genes expressed similarly with the ones in the microarray transcriptional profiles. The Se-related genes were categorized into 6 cellular components, 8 molecular functions, 44 biological processes, 10 pathways, and 1 network by STRING. The Se-related gene insulin-like growth factor binding protein 2 (IGFBP2), insulin-like growth factor binding protein 3 (IGFBP3), interleukin 6 (IL6), BCL2, apoptosis regulator (BCL2), and BCL2-associated X, apoptosis regulator (BAX), which involved in many molecular functions, biological processes, and apoptosis pathway may play important roles in the pathogenesis of KBD.

Imbalance of dietary nutrients and the associated differentially expressed genes and pathways may play important roles in juvenile Kashin-Beck disease

BACKGROUND

Kashin-Beck disease (KBD) is a childhood-onset endemic osteoarthropathy in China. Nutrients including trace elements may play active roles in the development of KBD.

OBJECTIVE

This study aimed to estimate the nutrient intakes of children in endemic areas and to identify the imbalanced nutrients associated differentially expressed genes in the juvenile patients with KBD.

METHODS

In this cross-sectional study, a consecutive 3 day 24 h semi-quantitative dietary retrospect questionnaire was conducted to estimate the daily nutrient intakes of children using CDGSS 3.0 software. Gene profile analysis was employed to identify differentially expressed genes in peripheral blood mononuclear cells of children with KBD. GOC, CTD, KEGG, and REACTOME databases were used to establish the relationship between nutrients and nutrients-associated differentially expressed genes and pathways. Statistical analyses were accomplished by SPSS 18.0 software.

RESULTS

Daily Se intakes without supplementation of children were significantly lower in Se-supplemented (Se + ) KBD areas (29.3 ∼ 29.6 mg/d) and non-endemic area (27.8 ± 7.9 mg/d) compared to non-Se-supplemented (Se-) KBD area (32.9 ± 7.9 mg/d, c² = 20.24, P < .01). Children in Se+ KBD areas were suffering more serious insufficient intake of multiple nutrients, including vitamins-B₂/-C/-E, Ca, Fe, Zn and I. Gene profile analysis combined with bioinformatics technique identified 34 nutrients associated differentially expressed genes and 10 significant pathways which are related to the pathological changes in juvenile KBD.

CONCLUSIONS

Imbalance of dietary nutrients and nutrients-associated differentially expressed genes and pathways may play important roles in the development of juvenile KBD.

Zinc: the Other Suspected Environmental Factor in Kashin-Beck Disease in Addition to Selenium

Kashin-Beck disease (KBD) is an endemic chronic osteochondral disease characterized by high prevalence, disability, and morbidity and is distributed from the northeast to the southwest in China, in some regions of Eastern Siberia in Russia, and in North Korea. Although the selenium deficiency etiological hypothesis for KBD has been proposed by scientists for decades, the idea that selenium deficiency is one of the most important environmental factors but not the primary and sole pathogenic factor for KBD has been widely accepted. Zn2+, which is closely involved in the synthesis of enzymes, nucleic acids, and proteins, is an essential microelement in vivo. A conundrum still exists in research on the relationship between Zn2+ and KBD due to inconsistent results, but it has been confirmed that Zn2+ can help repair metaphyseal lesions in patients with KBD, indicating that Zn2+ might play a key role in the pathogenesis of KBD, although the mechanism is unknown. The zinc-ZIP8-MTF1 axis in chondrocytes forms a catabolic cascade that promotes upregulation of the crucial effector matrix-degrading enzymes MMP3, MMP13, and ADAMTS5, thereby leading to osteoarthritis (OA) cartilage destruction. Zinc finger protein-related genes, the ZNT family, and the ZIP family of Zn2+ transporter genes have been found to be differentially expressed in KBD by high-throughput screening. Therefore, Zn2+ could play a key role in the pathogenesis of KBD.