Effect of lentivirus-mediated growth and differentiation factor-5 transfection on differentiation of rabbit nucleus pulposus mesenchymal stem cells

Background Intervertebral disc degeneration (IDD) is a natural progression of age-related processes. Associated with IDD, degenerative disc disease (DDD) is a pathologic condition implicated as a major cause of chronic lower back pain, which can have a severe impact on the quality of life of patients. As degeneration progression is associated with elevated levels of inflammatory cytokines, enhanced aggrecan and collagen degradation, and changes in the disc cell phenotype. The purpose of this study was to investigate the biological and cytological characteristics of rabbit nucleus pulposus mesenchymal stem cells (NPMSCs)—a key factor in IDD—and to determine the effect of the growth and differentiation factor-5 (GDF5) on the differentiation of rabbit NPMSCs transduced with a lentivirus vector. Methods An in vitro culture model of rabbit NPMSCs was established and NPMSCs were identified by flow cytometry (FCM) and quantitative real-time PCR (qRT-PCR). Subsequently, NPMSCs were randomly divided into three groups: a transfection group (the lentiviral vector carrying GDF5 gene used to transfect NPMSCs); a control virus group (the NPMSCs transfected with an ordinary lentiviral vector); and a normal group (the NPMSCs alone). FCM, qRT-PCR, and western blot (WB) were used to detect the changes in NPMSCs. Results The GDF5-transfected NPMSCs displayed an elongated shape, with decreased cell density, and significantly increased GDF5 positivity rate in the transfected group compared to the other two groups (P < 0.01). The mRNA levels of Krt8, Krt18, and Krt19 in the transfected group were significantly higher in comparison with the other two groups (P < 0.01), and the WB results were consistent with that of qRT-PCR. Conclusions GDF5 could induce the differentiation of NPMSCs. The lentiviral vector carrying the GDF5 gene could be integrated into the chromosome genome of NPMSCs and promoted differentiation of NPMSCs into nucleus pulposus cells. Our findings advance the development of feasible and effective therapies for IDD.

Serum Growth Differentiation Factor 15 Levels Are Associated With Depression After Ischemic Stroke

Background The effect of serum growth differentiation factor 15 (GDF‐15) on poststroke depression (PSD) remains unknown. This study aimed to investigate the association between serum GDF‐15 and PSD among patients with ischemic stroke. Methods and Results This study was based on a random sample from CATIS (China Antihypertensive Trial in Acute Ischemic Stroke). A total of 572 patients from 7 participating hospitals with GDF‐15 levels were included in this analysis. The study outcome was depression (Hamilton Depression Rating Scale score ≥8) at 3 months after ischemic stroke. A total of 231 (40.4%) patients with stroke experienced PSD within 3 months. The multivariate‐adjusted odds ratio of PSD associated with the highest tertile of serum GDF‐15 was 2.92 (95% CI, 1.36–6.27) compared with the lowest tertile. Each SD increase in log‐transformed GDF‐15 was associated with a 42% (95% CI, 2%–97%) increased risk of PSD, and a linear association between serum GDF‐15 and the risk of PSD was observed ( P for linearity=0.006). Conclusions Elevated serum GDF‐15 levels in the acute phase of ischemic stroke were independently associated with PSD, suggesting that GDF‐15 may be a valuable prognostic biomarker for PSD.

Integrated Analyses of Growth Differentiation Factor-15 Concentration and Cardiometabolic Diseases in Humans

Growth differentiation factor 15 (GDF15) is a stress response cytokine that is elevated in several cardiometabolic diseases and has attracted interest as a potential therapeutic target. To further explore the association of GDF15 with human disease, we conducted a broad study into the phenotypic and genetic correlates of GDF15 concentration in up to 14,099 individuals. Assessment of 772 traits across 6,610 participants in FINRISK identified associations of GDF15 concentration with a range of phenotypes including all-cause mortality, cardiometabolic disease, respiratory diseases and psychiatric disorders as well as inflammatory markers. A meta-analysis of genome-wide association studies (GWAS) of GDF15 concentration across 3 different assay platforms (n=14,099) confirmed significant heterogeneity due to a common missense variant rs1058587 in GDF15, potentially due to epitope-binding artefacts. After conditioning on rs1058587, statistical fine-mapping identified 4 independent putative causal signals at the locus. Mendelian randomisation (MR) analysis did not find evidence of a causal relationship between GDF15 concentration and cardiometabolic traits. Using reverse MR, we identified a potential causal association of body mass index on GDF15 (IVW pFDR=0.0072). Taken together, our data do not support a role for elevated GDF15 concentrations as a causal factor in human cardiometabolic disease but support its role as a biomarker of metabolic stress.

Associations between Sex Hormones and Circulating Growth Differentiation Factor-15 in Male Patients with Major Depressive Disorder

The interaction between the endocrine system and inflammation is crucial pathogenesis of depression. Our study aimed at exploring the possible relationship between sex hormones and growth differentiation factor-15 (GDF-15), a common indicator of inflammation in male patients with major depressive disorder (MDD). Methods: GDF-15 levels of 121 male MDD patients were compared with 105 healthy subjects with the help of a Cobas 8000 automatic chemiluminescence immunoanalyzer. Results: (1) MDD patients showed higher GDF-15 levels, a lower testosterone (T) level and testosterone/estradiol ratio (T/E2 ratio) than healthy subjects (all p < 0.05). (2) Serum T levels and the T/E2 ratio were inversely associated with GDF-15 serum levels (all p < 0.05). (3) HAMD-24 scores were positively correlated with the levels of GDF-15 (p < 0.01), but not with T levels, estradiol (E2) levels, and the T/E2 ratio (all p > 0.05). Conclusion: The high level of GDF-15 was correlated with a low T/E2 ratio and T deficiency in male MDD patients. The above results demonstrate that up-regulation of serum GDF-15 and down-regulation of T and T/E2 ratio may be correlated with the occurrence and severity of depression. So, changing the level of GDF-15 by regulating the proportion of sex hormones may play a key role in the prognosis and treatment of depression.