The hematopoietic-specific transmembrane protein tyrosine phosphatase CD45 functions to regulate Src kinases required for T- and B-cell antigen receptor signal transduction. So far, there have been no reports to our knowledge of a human deficiency in a tyrosine-specific phosphatase. Here, we identified a male patient with a deficiency in CD45 due to a large deletion at one allele and a point mutation at the other. The point mutation resulted in the alteration of intervening sequence 13 donor splice site. The patient presented at 2 months of age with severe combined immunodeficiency disease. The population of peripheral blood T lymphocytes was greatly diminished and unresponsive to mitogen stimulation. Despite normal B-lymphocyte numbers, serum immunoglobulin levels decreased with age. Thus, CD45 deficiency in humans results in T- and B-lymphocyte dysfunction.

No abstract

Nephrin is a cell adhesion protein located at the slit diaphragm area of glomerular podocytes. Mutations in nephrin-coding gene (NPHS1) cause congenital nephrotic syndrome (NPHS1). We studied the developmental expression of nephrin, ZO-1 and P-cadherin in normal fetal kidneys and in NPHS1 kidneys. We used in situ hybridization and immunohistochemistry at light and electron microscopic levels. Nephrin and zonula occludens-1 (ZO-1) were first expressed in late S-shaped bodies. During capillary loop stage, nephrin and ZO-1 localized at the basal margin and in the cell-cell adhesion sites between developing podocytes, especially in junctions with ladder-like structures. In mature glomeruli, nephrin and ZO-1 concentrated at the slit diaphragm area. P-cadherin was first detected in ureteric buds, tubules, and vesicle stage glomeruli. Later, P-cadherin was seen at the basal margin of developing podocytes. Fetal NPHS1 kidneys with Fin-major/Fin-major genotype did not express nephrin, whereas the expression of ZO-1 and P-cadherin was comparable to that of control kidneys. Although early junctional complexes proved structurally normal, junctions with ladder-like structures and slit diaphragms were completely missing. The results indicate that nephrin is dispensable for early development of podocyte junctional complexes. However, nephrin appears to be essential for formation of junctions with ladder-like structures and slit diaphragms.

The adrenal cortex is divided into concentric zones. In humans the major cortical zones are the zona glomerulosa, zona fasciculata, and zona reticularis. The adrenal cortex is a dynamic organ in which senescent cells are replaced by newly differentiated ones. This constant renewal facilitates organ remodeling in response to physiological demand for steroids. Cortical zones can reversibly expand, contract, or alter their biochemical profiles to accommodate needs. Pools of stem/progenitor cells in the adrenal capsule, subcapsular region, and juxtamedullary region can differentiate to repopulate or expand zones. Some of these pools appear to be activated only during specific developmental windows or in response to extreme physiological demand. Senescent cells can also be replenished through direct lineage conversion; for example, cells in the zona glomerulosa can transform into cells of the zona fasciculata. Adrenocortical cell differentiation, renewal, and function are regulated by a variety of endocrine/paracrine factors including adrenocorticotropin, angiotensin II, insulin-related growth hormones, luteinizing hormone, activin, and inhibin. Additionally, zonation and regeneration of the adrenal cortex are controlled by developmental signaling pathways, such as the sonic hedgehog, delta-like homolog 1, fibroblast growth factor, and WNT/β-catenin pathways. The mechanisms involved in adrenocortical remodeling are complex and redundant so as to fulfill the offsetting goals of organ homeostasis and stress adaptation.

BACKGROUND: Linkage and knock-out mice studies suggest that the melanocortin-3-receptor (MC3R) is a candidate gene for obesity. OBJECTIVE: To evaluate whether MC3R mutations underlie morbid obesity. SUBJECTS AND METHODS: MC3R coding and 5 0 -flanking regions were sequenced in 48 subjects and the detected variants genotyped in 252 morbidly obese (BMI ! 40 kg/m 2 ) Finns. Gel shifts were used to examine whether a mutation in the putative promoter alters GATA-factor binding. RESULTS: Three common MC3R variants were found: a 17C > A variant, changing Thr6?Lys in 16%, a 241G > A variant changing Val81?Ile in 15%, and a 7239A > G substitution in the GATA binding site in 21% of the subjects. Four other variants were detected in the 5 0 flanking region. Frequencies of the three common variants did not differ between obese and contol subjects. Among the obese, the 17C > A and 241G > A variants were coinherited and associated with increased insulin -glucose ratios (P < 0.05) and leptin levels (P < 0.05). GATA-4 bound efficiently to wild type oligonucleotide, but only weakly to the oligonucleotide with the 7239A > G mutation. CONCLUSIONS: MC3R gene variants are common and do not explain human morbid obesity. These variants associated with subtle changes in onset of weight gain, hyperleptinemia and insulin -glucose ratios. The 7239A > G mutation abolishes binding of GATA-4 to the MC3R promoter region.

Unresectable malignant liver tumors may be treated by LTx. We evaluated the results of LTx for HB and HCC. All patients transplanted for HB or HCC between 1990 and 2007 were included. Effects of histologic tumor type, primary tumor resection, disease staging, and serum AFP levels at diagnosis and at transplantation on disease recurrence and survival were evaluated. Twelve patients with median age of five (range, 2-16) were transplanted and followed for a median of 11 (2-18) yr. Six patients had HB and six had HCC. At diagnosis, eight patients were staged as PRETEXT III and four patients as PRETEXT IV. Two patients had pulmonary metastases. All patients received neoadjuvant chemotherapy. Median time from diagnosis to LTx was seven (2-133) months. At LTx, none of the patients had radiological evidence of extrahepatic disease, and the median AFP level was 85 (6-15 180) microg/L. No routine chemotherapy after LTx was used.The overall one-, five-, and 10-yr cumulative survival rates were 100%, 80%, and 67%, respectively. Survival was comparable between the two tumor types (4/6 for both). Two deaths occurred secondary to tumor recurrence, one of each tumor type. Both of these patients had an AFP response of <99%. Six of eight patients with primary LTx survived, when compared to two of four transplanted after primary resection. PRETEXT tumor staging had no effect on survival. LTx even without post-transplantation chemotherapy is an effective treatment option for unresectable HB and HCC with comparable survival. Incomplete AFP response to chemotherapy and primary tumor resection were associated with decreased survival.

No abstract

Transcription factor GATA4 is expressed in somatic cells of the mammalian testis. Gene targeting studies in mice have shown that GATA4 is essential for proper differentiation and function of Sertoli cells. The role of GATA4 in Leydig cell development, however, remains controversial, because targeted mutagenesis experiments in mice have not shown a consistent phenotype, possibly due to context-dependent effects or compensatory responses. We therefore undertook a reductionist approach to study the function of GATA4 in Leydig cells. Using microarray analysis and quantitative RT-PCR, we identified a set of genes that are down-regulated or up-regulated after small interfering RNA (siRNA)-mediated silencing of Gata4 in the murine Leydig tumor cell line mLTC-1. These same genes were dysregulated when primary cultures of Gata4(flox/flox) adult Leydig cells were subjected to adenovirus-mediated cre-lox recombination in vitro. Among the down-regulated genes were enzymes of the androgen biosynthetic pathway (Cyp11a1, Hsd3b1, Cyp17a1, and Srd5a). Silencing of Gata4 expression in mLTC-1 cells was accompanied by reduced production of sex steroid precursors, as documented by mass spectrometric analysis. Comprehensive metabolomic analysis of GATA4-deficient mLTC-1 cells showed alteration of other metabolic pathways, notably glycolysis. GATA4-depleted mLTC-1 cells had reduced expression of glycolytic genes (Hk1, Gpi1, Pfkp, and Pgam1), lower intracellular levels of ATP, and increased extracellular levels of glucose. Our findings suggest that GATA4 plays a pivotal role in Leydig cell function and provide novel insights into metabolic regulation in this cell type.