Cross-species analyses implicate Lipin 1 involvement in human glucose metabolism
ABSTRACT Recent studies in the mouse have demonstrated that variations in lipin expression levels in adipose tissue have marked effects on adipose tissue mass and insulin sensitivity. In the mouse, lipin deficiency prevents normal adipose tissue development, resulting in lipodystrophy and insulin resistance, whereas excess lipin levels promote fat accumulation and insulin sensitivity. Here, we investigated the effects of genetic variation in lipin levels on glucose homeostasis across species by analyzing lipin transcript levels in human and mouse adipose tissues. A strong negative correlation was observed between lipin mRNA levels and fasting glucose and insulin levels, as well as an indicator of insulin resistance (HOMA-IR), in both mice and humans. We subsequently analyzed the allelic diversity of the LPIN1 gene in dyslipidemic Finnish families, as well as in a case-control sample of obese (n = 477) and lean (n = 821) individuals. Alleles were defined by genotyping seven single nucleotide polymorphisms (SNPs) of the critical DNA region over the LPIN1 gene. Intragenic SNPs and corresponding allelic haplotypes exhibited associations with serum insulin levels and body mass index (P = 0.002-0.04). Both the expression levels in adipose tissue across species and genetic data in human study samples highlight the importance of lipin in glucose homeostasis and imply that allelic variants of this gene have significance in human metabolic traits.
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- "In accordance with the reports from natural human population, in our experiment chicken hepatic Lpin1 gene mRNA expression level presented significantly negative correlation with abdominal adipose deposition (AFR; P , 0.01). It was reported that Lpin1 mRNA expression had a strong negative correlation with GLU and INS levels in mouse and human, TG levels in human (Suviolahti et al., 2006). Lpin1 "
ABSTRACT: Lpin1 was a gene with important effects on controlling lipid/energy metabolism in humans and mice. However, little was known about chicken Lpin1 gene. In the present study, two transcript isoforms of chicken Lpin1 were identified. Lpin1-α was predicted encoding one 902 amino acid protein, whereas Lpin1-δ was predicted encoding one 918 amino acid protein with an insertion of 48-bp fragment from intron 12 of chicken Lpin1-α, and a conservative element was found to be located in intron 12 of chicken Lpin1-α genomic sequence. Ten variants were identified from chicken Lpin1-α coding sequence, and two missense mutations were predicted to affect the protein function of Lpin1. Reverse transcription PCR (RT-PCR) analysis revealed that chicken total Lpin1, Lpin1-α and Lpin1-δ were expressed in all analyzed tissues, and presented clear tissue expression differences. Real-time quantitative RT-PCR revealed that 30% energy restriction significantly elevated the total Lpin1 mRNA expression level in hepatic (P < 0.01) and adipose (P < 0.01) tissues of birds. Chicken total Lpin1 gene mRNA expression level presented a significantly inverse correlation with some traits including abdominal fat rate (P < 0.01), serum high-density lipoprotein (P < 0.05) and total cholesterol (P < 0.05), which would make a foundation for the further study on chicken Lpin1 gene function.animal 07/2012; 6(12):1897-903. DOI:10.1017/S1751731112001358 · 1.78 Impact Factor
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- "Regarding human obesity, very few reports on human LPIN1 gene expression have been performed, suggesting a positive association with insulin sensitivity    and a negative one with body mass index (BMI)  . On the other hand, human immunodeficiency virus (HIV)-infected patients who developed lipodystrophy had lower LPIN1 messenger RNA (mRNA) levels than those without lipodystrophy , in line with findings in the fld animal model . "
ABSTRACT: The aim of this study was to analyze LPIN1 adipose tissue gene expression levels in 3 clinical insulin-resistant conditions-obesity, type 2 diabetes mellitus, and human immunodeficiency virus (HIV)-associated lipodystrophy-and its relationship with adipogenic and inflammatory markers. Subcutaneous adipose tissue samples were obtained from 2 cohorts: 98 subjects with different degrees of adiposity and with or without the presence of type 2 diabetes mellitus and 37 HIV-infected patients. Real-time polymerase chain reaction was used to measure gene expression of LPIN1 and adipogenic (PPARgamma, SREBP1c) and inflammatory markers (IL6, TNFalpha, TNFR1, and TNFR2). LPIN1 messenger RNA expression levels were significantly lower in the obese group (P = .002), were similar in type 2 diabetes mellitus patients and control subjects (P = .211), and were significantly higher in HIV-infected patients (P < .001). LPIN1 messenger RNA levels positively correlated with insulin sensitivity in all subjects. Moreover, an inverse correlation with proinflammatory cytokines was observed.Metabolism 11/2007; 56(11):1518-26. DOI:10.1016/j.metabol.2007.06.019 · 3.61 Impact Factor
Conference Paper: Adaptive inverse control based on linear and nonlinear adaptivefiltering[Show abstract] [Hide abstract]
ABSTRACT: At present, the control of a dynamic system (the “plant”) is generally done by means of feedback. This paper proposes an alternative approach that uses adaptive filtering to achieve feedforward control for both linear and nonlinear plants. Precision is attained because of the feedback incorporated in the adaptive filtering. Disturbance in the plant can be optimally controlled by a special circuit that obtains the disturbance at the plant output, filters it, and feeds it back into the plant input. The circuit works in such a way that the feedback does not alter the plant dynamic response. The concept of adaptive inverse control has application to both linear and nonlinear, MIMO and SISO plantsNeural Networks for Identification, Control, Robotics, and Signal/Image Processing, 1996. Proceedings., International Workshop on; 09/1996