Insulin resistance is a major cause of type 2 diabetes mellitus (T2DM). Resistin, an adipocyte-secreted hormone, antagonizes insulin. Transgenic mice that overexpress the resistin gene (Retn) in adipose tissue are insulin-resistant, whereas Retn (-/-) mice show lower fasting blood glucose, suggesting that the altered Retn promoter function could cause diabetes. To determine the role of RETN in human T2DM, we analyzed polymorphisms in its 5' flanking region. We found that the -420G/G genotype was associated with T2DM (397 cases and 406 controls) (P=.008; adjusted odds ratio = 1.97 [by logistic regression analysis]) and could accelerate the onset of disease by 4.9 years (P=.006 [by multiple regression analysis]). Meta-analysis of 1,888 cases and 1,648 controls confirmed this association (P=.013). Linkage disequilibrium analysis revealed that the -420G/G genotype itself was a primary variant determining T2DM susceptibility. Functionally, Sp1 and Sp3 transcription factors bound specifically to the susceptible DNA element that included -420G. Overexpression of Sp1 or Sp3 enhanced RETN promoter activity with -420G in Drosophila Schneider line 2 cells that lacked endogenous Sp family members. Consistent with these findings, fasting serum resistin levels were higher in subjects with T2DM who carried the -420G/G genotype. Therefore, the specific recognition of -420G by Sp1/3 increases RETN promoter activity, leading to enhanced serum resistin levels, thereby inducing human T2DM.

OBJECTIVE -Resistin, secreted from adipocytes, causes insulin resistance in rodents. We previously reported that the G/G genotype of a resistin gene promoter single nucleotide polymorphism (SNP) at Ϫ420 increases type 2 diabetes susceptibility by enhancing promoter activity. We report here on the relation between plasma resistin and either SNP Ϫ420 genotype or factors related to insulin resistance. RESEARCH DESIGN AND METHODS-We cross-sectionally analyzed 2,078 community-dwelling Japanese subjects attending a yearly medical checkup. The SNP Ϫ420 genotype was determined by TaqMan analysis. Fasting plasma resistin was measured using an enzyme-linked immunosorbent assay kit.RESULTS -Plasma resistin was associated with the SNP Ϫ420 genotype (P Ͻ 0.0001), which was highest in G/G followed by C/G and C/C. Plasma resistin was higher in elderly individuals, female subjects, nondrinkers, and subjects with high blood pressure (P Ͻ 0.001, 0.003, Ͻ0.001, and 0.001, respectively). Simple regression analysis revealed that age, female sex, homeostasis model assessment of insulin resistance (HOMA-IR) index, systolic blood pressure, low HDL cholesterol, and high-sensitivity C-reactive protein (hs-CRP) were positively correlated with plasma resistin (P Ͻ 0.001, 0.003, Ͻ0.001, 0.004, Ͻ0.001, and 0.003, respectively). Multiple regression analysis adjusted for age, sex, and BMI revealed that plasma resistin was an independent factor for HOMA-IR, low HDL cholesterol, and hs-CRP (P ϭ 0.001, Ͻ0.001, and 0.006, respectively).CONCLUSIONS -Plasma resistin was associated with SNP Ϫ420 and was correlated with insulin resistance, low serum HDL cholesterol, and high hs-CRP in the Japanese general population.

Zinc-fingers and homeoboxes (ZHX) 1 is a transcription factor that interacts with the activation domain of the A subunit of nuclear factor-Y (NF-YA). Using a yeast two-hybrid system, a novel ubiquitous transcription factor ZHX2 as a ZHX1-interacting protein was cloned. ZHX2 consists of 837 amino acid residues and contains two zinc-finger motifs and five homeodomains (HDs) as well as ZHX1. The mRNA is expressed among various tissues. ZHX2 not only forms a heterodimer with ZHX1, but also forms a homodimer. Moreover, ZHX2 interacts with the activation domain of NF-YA. Further analysis revealed that ZHX2 is a transcriptional repressor that is localized in the nuclei. Since ZHX2 shares a number of properties in common with ZHX1, we conclude that all these come under the ZHX family. The minimal functional domains of ZHX2 were then characterized. The dimerization domain with both ZHX1 and ZHX2 is the region containing HD1, the domain that interacts with NF-YA is the HD1 to HD2 region, the repressor domain is the HD1 to a proline-rich region. Lastly, using an immunoprecipitation assay, we showed that ZHX2 intrinsically interacts with NF-YA in HEK-293 cells and that ZHX2 represses the promoter activity of the cdc25C gene stimulated by NF-Y in Drosophila Schneider line 2 cells. Thus the ZHX family of proteins may participate in the expression of a number of NF-Y-regulated genes via a more organized transcription network.

Adult stem cells from bone marrow, referred to as mesenchymal stem cells or marrow stromal cells (MSCs), are defined as pluripotent cells and have the ability to differentiate into multiple mesodermal cells. In this study, we investigated whether MSCs from rat, mouse, and human are able to differentiate into steroidogenic cells. When transplanted into immature rat testes, adherent marrow-derived cells (including MSCs) were found to be engrafted and differentiate into steroidogenic cells that were indistinguishable from Leydig cells. Isolated murine MSCs transfected with green fluorescence protein driven by the promoter of P450 side-chain cleaving enzyme gene (CYP11A), a steroidogenic cell-specific gene, were used to detect steroidogenic cell production in vitro. During in vitro differentiation, green fluorescence protein-positive cells, which had characteristics similar to those of Leydig cells, were found. Stable transfection of murine MSCs with a transcription factor, steroidogenic factor-1, followed by treatment with cAMP almost recapitulated the properties of Leydig cells, including the production of testosterone. Transfection of human MSCs with steroidogenic factor-1 also led to their conversion to steroidogenic cells, but they appeared to be glucocorticoid- rather than testosterone-producing cells. These results indicate that MSCs represent a useful source of stem cells for producing steroidogenic cells that may provide basis for their use in cell and gene therapy.

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Currently, there is no satisfactory treatment for Raynaud's phenomenon (RP) in systemic sclerosis (SSc). Recently, it has been reported that botulinum toxin A (BTX-A) injection was effective for the treatment of RP in SSc patients. The objective was to assess the efficacy and safety of BTX-A on RP in Japanese SSc patients. In the prospective, case series study, 10 Japanese SSc patients with RP received 10 U of BTX-A injections into the hand. The change in severity of RP, including the frequency of attacks/pain, color changes, duration time of RP and the severity of pain, was assessed by Raynaud's score and pain visual analog scale (VAS) at each visit during 16 weeks. The recovery of skin temperature 20 min after cold water stimulation was examined by thermography at baseline and 4 weeks after injection. The number of digital ulcers (DU) and adverse effects were assessed at each visit. BTX-A injection decreased Raynaud's score and pain VAS from 2 weeks after injection, and the suppressive effect was continued until 16 weeks after injection. Skin temperature recovery after cold water stimulation at 4 weeks after injection was significantly enhanced compared with that before injection. All DU in five patients were healed within 12 weeks after injection. Neither systemic nor local adverse effects were observed in all cases. We conclude that BTX-A injection significantly improved the activity of RP in SSc patients without any adverse events, suggesting that BTX-A may have possible long-term preventive and therapeutic potentials for RP in Japanese SSc patients.

Mammalian pyruvate kinase (PK), a key glycolytic enzyme, has two genes named PKL and PKM, which produce the L- and R-type isoenzymes by means of alternative promoters, and the M1-and M2-types by mutually exclusive alternative splicing respectively. The expression of these genes is tissue-specific and under developmental, dietary and hormonal control. The L-type isoenzyme (L-PK) gene contains multiple regulatory elements necessary for regulation in the 5' flanking region, up to position -170. Both L-II and L-III elements are required for stimulation of L-PK gene transcription by carbohydrates such as glucose and fructose, although the L-III element is itself responsive to carbohydrates. The L-II element is also responsible for the gene regulation by polyunsaturated fatty acids. Nuclear factor-1 proteins and hepatocyte nuclear factor 4, which bind to the L-II element, may also be involved in carbohydrate and polyunsaturated fatty acid regulation of the L-PK gene respectively. However, the L-III-element-binding protein that is involved in carbohydrate regulation remains to be clarified, although involvement by an upstream stimulating factor has been proposed. Available evidence suggests that the carbohydrate signalling pathway to the L-PK gene includes a glucose metabolite, possibly glucose 6-phosphate or xylulose 5-phosphate, as well as phosphorylation and dephosphorylation mechanisms. In addition, at least five regulatory elements have been identified in the 5' flanking region of the PKM gene up to position -279. Sp1-family proteins bind to two proximal elements, but the binding of proteins to other elements have not yet been clarified. Glucose may stimulate the transcription of the PKM gene via hexosamine derivatives. Sp1 may be involved in this regulation via its dephosphorylation, although the carbohydrate response element has not been determined precisely in the PKM gene. Thus glucose stimulates transcription of the PKM gene by the mechanism which is probably different from the L-PK gene.

The efficacy and safety of botulinum toxin B (BTX-B) for treatment of Raynaud's phenomenon and digital ulcers in patients with systemic sclerosis was assessed. A total of 45 patients with systemic sclerosis who had Raynaud's phenomenon were blinded and divided randomly into 4 groups: a no-treatment control group, and 3 treatment groups, using 250, 1,000 or 2,000 international units (U) of BTX-B injections in the hand with more severe symptoms. Four weeks after injection, pain/numbness visual analogue scale scores and Raynaud's score in the groups treated with 1,000 and 2,000 U BTX-B were significantly lower than in the control group and the group treated with 250 U BTX-B. These beneficial effects were sustained until 16 weeks after the single injection. At 4 weeks after injection skin temperature recovery in the group treated with 2,000 U BTX-B was significantly improved. The numbers of digital ulcers in the groups treated with 1,000 and 2,000 U BTX-B were significantly lower than in the control group. In conclusion, 1,000 and 2,000 U BTX-B injections significantly suppressed the activity of Raynaud's phenomenon and digital ulcers in patients with SSc without serious adverse events.