Macrophage Inhibitory Cytokine 1 (MIC-1/GDF15) Decreases Food Intake, Body Weight and Improves Glucose Tolerance in Mice on Normal & Obesogenic Diets

Food intake and body weight are controlled by a variety of central and peripheral factors, but the exact mechanisms behind these processes are still not fully understood. Here we show that that macrophage inhibitory cytokine-1 (MIC-1/GDF15), known to have anorexigenic effects particularly in cancer, provides protection against the development of obesity. Both under a normal chow diet and an obesogenic diet, the transgenic overexpression of MIC-1/GDF15 in mice leads to decreased body weight and fat mass. This lean phenotype was associated with decreased spontaneous but not fasting-induced food intake, on a background of unaltered energy expenditure and reduced physical activity. Importantly, the overexpression of MIC-1/GDF15 improved glucose tolerance, both under normal and high fat-fed conditions. Altogether, this work shows that the molecule MIC-1/GDF15 might be beneficial for the treatment of obesity as well as perturbations in glucose homeostasis

Gadd45g Is Essential for Primary Sex Determination, Male Fertility and Testis Development

<div><p>In humans and most mammals, differentiation of the embryonic gonad into ovaries or testes is controlled by the Y-linked gene <i>SRY</i>. Here we show a role for the Gadd45g protein in this primary sex differentiation. We characterized mice deficient in Gadd45a, Gadd45b and Gadd45g, as well as double-knockout mice for Gadd45ab, Gadd45ag and Gadd45bg, and found a specific role for Gadd45g in male fertility and testis development. <i>Gadd45g</i>-deficient XY mice on a mixed 129/C57BL/6 background showed varying degrees of disorders of sexual development (DSD), ranging from male infertility to an intersex phenotype or complete gonadal dysgenesis (CGD). On a pure C57BL/6 (B6) background, all Gadd45g^−/− XY mice were born as completely sex-reversed XY-females, whereas lack of Gadd45a and/or Gadd45b did not affect primary sex determination or testis development. <i>Gadd45g</i> expression was similar in female and male embryonic gonads, and peaked around the time of sex differentiation at 11.5 days post-coitum (dpc). The molecular cause of the sex reversal was the failure of Gadd45g^−/− XY gonads to achieve the SRY expression threshold necessary for testes differentiation, resulting in ovary and Müllerian duct development. These results identify <i>Gadd45g</i> as a candidate gene for male infertility and 46,XY sex reversal in humans.</p> </div

Gadd45g is necessary for <i>SRY</i> expression and testis development at the time of primary sex determination of the bipotential embryonic gonad.

<p>(A) RT-PCR quantification of relative <i>Gadd45g</i> expression in B6 wild type XX and XY embryonic gonads (including mesonephros), collected between 10.5 (8 tail somites) and 12.5 dpc (28 tail somites). In all images, the dashed red line denotes the point of maximal <i>SRY</i> expression (11.5 dpc or 18 tail somites). (B) Microarray quantification of relative <i>Gadd45g</i> expression in normal wild type XX and XY embryonic gonads (including mesonephros) from the time of the bipotential gonad (GEO data set GSE6916). (C) Microarray quantification of relative <i>Gadd45g</i> expression in purified somatic support precursor cells during the critical sex determination period (10.5–11.5 dpc) (GEO data set GDS1724). (D) RT-PCR quantification of <i>SRY</i> copy numbers in Gadd45g^+/+, Gadd45g^+/− and Gadd45g^−/− gonads (including mesonephros) between 10.5–12.5 dpc. (E) RT-PCR quantification (mean and SEM) of SRY copy numbers in Gadd45g^+/+, Gadd45g^+/− and Gadd45g^−/− gonads (including mesonephros) at the 17 to 21 tail somite stage. Statistical analysis (Student’s t-test) of all data from Fig. 4D at the 17–18 or 19–20 tail somite stage showed reduced SRY expression in Gadd45g^−/− mice and delayed SRY upregulation in Gadd45g^+/− mice compared to wild type controls. Numbers for each group (<i>n</i>) are displayed in each column. (F) Main components of the transcriptional network around the time of primary sex determination and suggested mechanism of Gadd45g action. In the absence of <i>SRY</i> (XX gonads), female-specific genetic programs (such as the WNT4/beta-catenin pathway) direct differentiation of the somatic support lineage into granulosa cells and ovary development. In XY gonads, <i>SRY</i> expression at 11.5 dpc induces <i>SOX9</i> expression, Sertoli cell differentiation and testis cord formation. In males, Sertoli cell-derived anti-Müllerian hormone (AMH) induces Müllerian duct regression, and testosterone induces differentiation of the Wolffian duct into vas deferens, seminal vesicles and epididymis. AMH acts ipsilaterally, which explains the intersex phenotype shown in Fig. 1L. In Gadd45g-deficient mice, SRY expression in XY gonads fails to reach the threshold level necessary for testis differentiation. The dashed red line denotes the point of maximal SRY expression (11.5 dpc).</p

Frequency of sex reversal in distinct Gadd45g genotypes on 129/B6 or B6 backgrounds.

<p>(A) <i>SRY</i> genotyping showed that 100% of XY Gadd45g^−/− and 3% of Gadd45g^+/− mice on the B6 background, and (B) 80% of XY Gadd45g^−/− mice on the 129/B6 background were born as sex-reversed XY females. (C) Sex reversal in Gadd45g^−/− mice born as females was detected by PCR amplification of a 404-bp band from the Y chromosome <i>SRY</i> gene. (D) Presence of the Y chromosome in <i>SRY</i>-positive Gadd45g^−/− XY-F mice was confirmed by chromosome painting (FISH).</p

Complete or partial XY sex-reversed phenotype of XY Gadd45g^−/− mice on a pure B6 or mixed 129/B6 background.

<p>(A–F) External genitals, (G–L) internal reproductive organs (8x magnification), and (M–X) hematoxylin/eosin (HE)-stained gonad or epididymis sections from young adult Gadd45g^−/− and wild type mice. External and internal (C,I) reproductive organs from B6 Gadd45g^−/− XY female mice (XY-F) are morphologically indistinguishable from wild type females (B, H). HE-stained ovaries from all B6 XY-F mice appear normal and contain oocytes and follicles at different maturation stages (O), including antral follicles with oocytes (U). Corpora lutea are found in XX-F and XY-F ovaries (N,O,T,U). In contrast, a large spectrum of disorders of sexual development (DSD) is seen in Gadd45g^−/− XY mice on the 129/B6 background, which can be divided into three groups. 1) Infertile XY-females (E) with female internal reproductive organs (ovary, oviduct, uteri) (K), although the ovaries usually contain only primordial follicles and interstitial cells (Q,W). 2) Infertile XY-males with male phenotype (D) and reproductive system (J; testis, epididymis, vas deferens and seminal vesicles [not shown in J]) with hypoplastic testis (compare J to G). Seminiferous tubules showed reduced spermatogenesis and interstitial cell hyperplasia (P), and no spermatozoa were present in the cauda epididymis (V) and vas deferens. 3) XY-intersex mice (F) with male and female characteristics. External genitals were male, female, or ambiguous (as in F). One side often developed a hypoplastic testis/epididymis/vas deferens (L) and the contralateral gonad, a uterus and a hypoplastic ovary/oviduct/uterus or an ovotestis with mixed ovarian and testicular tissue (L,R,X). Magnification: 5x (N,O,Q,R) or 10x (M,P,S,T,U,V,W,X).</p

Lack of Gadd45g, but not Gadd45a or Gadd45b leads to male-to-female sex reversal in mice.

*<p>The number of sex-reversed XY females in Gadd45g^−/−, Gadd45g^+/− and Gadd45g^+/+ mice that also bear a hetero- or homozygous deletion of another Gadd45 family member (Gadd45a or Gadd45b).</p>§<p>The percentage of sex-reversed XY females in Gadd45g^−/−, Gadd45g^+/− and Gadd45g^+/+ mice that also bear a hetero- or homozygous deletion of another Gadd45 family member (Gadd45a or Gadd45b).</p><p>n.a., not available.</p

Lack of Sertoli cell differentiation and testis cord formation in XY Gadd45g^−/− gonads.

<p>(A–L) Confocal optical slices of whole mount immunostained B6 gonads (dashed outline), showing expression of Sertoli cell markers SOX9 (nuclear, blue) and AMH (cytoplasmic, red) and the germ/endothelial cell marker Pecam1 (membrane, green). (A) From 12.5 dpc, wild type male gonads can be distinguished morphologically from female gonads (B) by the appearance of testis cord structures containing SOX9-expressing Sertoli cells. (C) In Gadd45g^−/− XY gonads, only transient SOX9 expression was observed in a small number of somatic cells at 12.5 dpc. (D–F) and (J–L) are enlarged details of the images above. (G) At 13.5 dpc, all germ cells in male gonads are enclosed in testis cords and interact closely with a surrounding single layer of SOX9- and AMH-positive Sertoli cells. (H,I,K,L) No testis cord formation or AMH expression was induced in Gadd45g^+/+ XX (H,K) or in Gadd45g^−/− XY (I,L) gonads.</p

Serum macrophage inhibitory cytokine 1 in rheumatoid arthritis: a potential marker of erosive joint destruction

OBJECTIVE: The transforming growth factor beta superfamily member macrophage inhibitory cytokine 1 (MIC-1) is expressed upon macrophage activation, regulated by the p53 pathway, and linked to clinical events in atherosclerosis and cancer. Since rheumatoid arthritis (RA) shares similar etiopathologic mechanisms with the above diseases, we sought to determine the clinical utility of determining MIC-1 serum levels and MIC-1 genotype in the management of RA. METHODS: Ninety-one RA patients were recruited. Serum was collected from 83 of these patients and synovial biopsy samples were collected from the remaining 8 patients. Of the 83 patients from whom serum was collected, 61 were treated on an outpatient basis (defined as having nonsevere disease), and 22 patients went on to undergo hemopoietic stem cell transplantation (HSCT) (defined as having severe disease). RESULTS: Serum levels of MIC-1 were higher in RA patients and reflected disease severity independently of classic disease markers. MIC-1 was detected in rheumatoid synovial specimens, and allelic variation of MIC-1 was associated with earlier erosive disease and severe treatment-resistant chronic RA. Additionally, algorithms including serum and/or allelic variation in MIC-1 predicted response to HSCT, the presence of severe disease, and joint erosions. CONCLUSION: Determination of serum levels of MIC-1 and MIC-1 genotype may be clinically useful in the management of RA as well as in selection of patients for HSCT, since they predict disease course and response to therapy. The data indicate a potential role for MIC-1 in RA pathogenesis. These results warrant larger prospective studies to fully delineate and confirm a role for MIC-1 genotyping and serum estimation in patient selection for HSCT and in the management of R

The propeptide mediates formation of stromal stores of PROMIC-1: Role in determining prostate cancer outcome

The extracellular matrix (ECM) is a reservoir of cellular binding proteins and growth factors that are critical for normal cell behavior, and aberrations in the ECM invariably accompany malignancies such as prostate cancer. Carcinomas commonly overexpress macrophage inhibitory cytokine 1 (MIC-1), a proapoptotic and antitumorigenic transforming growth factor-β superfamily cytokine. Here we show that MIC-1 is often secreted in an unprocessed propeptide containing form. It is variably processed intracellularly, with unprocessed forms being secreted from several tumor lines, including prostate carcinoma lines, PC-3 and LNCaP. Once secreted, only unprocessed proMIC-1 binds ECM, demonstrating for the first time the occurrence of extracellular stores of MIC-1. The propeptide mediates this association via its COOH-terminal 89 amino acids. Xenograft models bearing tumors secreting various engineered forms of MIC-1 show that the propeptide regulates the balance between ECM stores and circulating serum levels of mature MIC-1 in vivo. The absence of propeptide results in ∼ 20-fold increase in serum MIC-1 levels. The significance of stromal MIC-1 stores was evaluated in prostate cancer tissue cores, which show major variation in stromal levels of MIC-1. Stromal MIC-1 levels are linked to prostate cancer outcome following radical prostatectomy, with decreasing stromal levels providing an important independent predictor of disease relapse. In low-grade localized prostate cancer (Gleason sum score ≤6), the level of MIC-1 stromal stores was the best predictor of future relapse when compared with all other clinicopathologic variables. The secretion and ECM association of unprocessed proMIC-1 is likely to play a central role in modulating local bioavailability of MIC-1 which can affect patient outcome in prostate cancer and other epithelial tumors