Sarcoidosis is a polygenic immune disorder with predominant manifestation in the lung. Genome-wide linkage analysis previously indicated that the extended major histocompatibility locus on chromosome 6p was linked to susceptibility to sarcoidosis. Here, we carried out a systematic three-stage SNP scan of 16.4 Mb on chromosome 6p21 in as many as 947 independent cases of familial and sporadic sarcoidosis and found that a 15-kb segment of the gene butyrophilin-like 2 (BTNL2) was associated with the disease. The primary disease-associated variant (rs2076530; P(TDT) = 3 x 10(-6), P(case-control) = 1.1 x 10(-8); replication P(TDT) = 0.0018, P(case-control) = 1.8 x 10(-6)) represents a risk factor that is independent of variation in HLA-DRB1. BTNL2 is a member of the immunoglobulin superfamily and has been implicated as a costimulatory molecule involved in T-cell activation on the basis of its homology to B7-1. The G --> A transition constituting rs2076530 leads to the use of a cryptic splice site located 4 bp upstream of the affected wild-type donor site. Transcripts of the risk-associated allele have a premature stop in the spliced mRNA. The resulting protein lacks the C-terminal IgC domain and transmembrane helix, thereby disrupting the membrane localization of the protein, as shown in experiments using green fluorescent protein and V5 fusion proteins.

TP63, an important epithelial developmental gene, has significant homology to p53. Unlike p53, the expression of p63 is regulated by two different promoters resulting in proteins with opposite functions: the full-length transcriptionally active TAp63 and the dominant-negative DNp63. We investigated the downstream mechanisms by which TAp63a elicits apoptosis. TAp63a directly transactivates the CD95 gene via the p53 binding site in the first intron resulting in upregulation of a functional CD95 death receptor. Stimulation and blocking experiments of the CD95, TNF-R and TRAIL-R death receptor systems revealed that TAp63a can trigger expression of each of these death receptors. Furthermore, our findings demonstrate a link between TAp63a and the mitochondrial apoptosis pathway. TAp63a upregulates expression of proapoptotic Bcl-2 family members like Bax and BCL2L11 and the expression of RAD9, DAP3 and APAF1. Of clinical relevance is the fact that TAp63a is induced by many chemotherapeutic drugs and that inhibiting TAp63 function leads to chemoresistance. Thus, beyond its importance in development and differentiation, we describe an important role for TAp63a in the induction of apoptosis and chemosensitivity.

We investigated the mechanisms by which TAp73b and dominant-negative p73 (DNp73) regulate apoptosis. TAp73b transactivated the CD95 gene via the p53-binding site in the first intron. In addition, TAp73b induced expression of proapoptotic Bcl-2 family members and led to apoptosis via the mitochondrial pathway. Endogenous TAp73 was upregulated in response to DNA damage by chemotherapeutic drugs. On the contrary, DNp73 conferred resistance to chemotherapy. Inhibition of CD95 gene transactivation was one mechanism by which DNp73 functionally inactivated the tumor suppressor action of p53 and TAp73b. Concomitantly, DNp73 inhibited apoptosis emanating from mitochondria. Thus, DNp73 expression in tumors selects against both the death receptor and the mitochondrial apoptosis activity of TAp73b. The importance of these data is evidenced by our finding that upregulation of DNp73 in hepatocellular carcinoma patients correlates with reduced survival. Our data indicate that DNp73 is an important gene in hepatocarcinogenesis and a relevant prognostic factor.

We have confirmed SOS1 as the second major gene for NS. Patients carrying mutations in this gene have a distinctive phenotype with frequent ectodermal anomalies such as keratosis pilaris and curly hair. However, the clinical picture associated with SOS1 mutations is different from that of CFCS. These findings corroborate that, despite being caused by gain-of-function mutations in molecules belonging to the same pathway, NS and CFCS scarcely overlap genotypically.

Interventions to block the renin-angiotensin system (RAS) halt the progression of renal lesions in renal damage models. It has recently also been reported that established glomerulosclerosis can be reversed by pharmacologic blockade of the RAS. It was the aim of this study to confirm that high doses of angiotensin-converting enzyme (ACE) inhibitors reverse established glomerulosclerosis and to extend the findings by providing quantitative information on glomerular geometry, podocytes and other glomerular cells, renal vessels and tubulointerstitial tissue. Male Sprague Dawley rats were subjected to subtotal surgical renal ablation (SNX) (n = 27) or sham operation (n = 31) and fed using a pair-feeding protocol. Eight weeks after surgery, rats were either sacrificed or allocated to two arms: enalapril treatment (48 mg/kg body wt per day administered in the drinking fluid for 4 wk) or no treatment. Renal morphology was evaluated after 8 or 12 wk, respectively, by stereology in tissue fixed by pressure-controlled perfusion. Both systolic BP and albumin excretion rate were significantly higher in SNX compared with sham-operated controls. They were significantly reduced in SNX after delayed enalapril treatment. The glomerulosclerosis (GSI), tubulointerstitial (TII), and vascular (VI) damage indices were significantly higher in all SNX groups than in sham-operated controls. At the end of the experiment (12 wk after SNX) GSI, TII, and VI were significantly lower in SNX with delayed enalapril treatment (0.77 +/- 0.18, 0.63 +/- 0.19 and 0.43 +/- 0.16, respectively) compared with untreated SNX (1.64 +/- 0.14, 1.16 +/- 0.34 and 0.67 +/- 0.29, respectively). GSI, TII, and VI were also significantly lower in SNX with delayed enalapril treatment compared with SNX sacrificed without treatment 8 wk after SNX. The same was true for glomerular volume. The number of podocytes was not affected by SNX, but podocyte volume was increased. Both indices remained unaffected by treatment. The numbers of cells within the mesangium and endothelial cells per glomerulus were significantly lower in SNX after delayed enalapril treatment compared with untreated SNX. These results strongly suggest regression of preexisting lesions, i.e., glomerular, tubular, and vascular remodeling as well as reversal of glomerular hypertrophy by ACE inhibitor treatment. The study confirms that high-dose ACE inhibitor treatment causes partial reversal of glomerular as well as interstitial lesions in subtotally nephrectomized rats.

Inhibition of cyclooxygenase (COX)-2 elicits chemopreventive and therapeutic effects in solid tumors that are coupled with the induction of apoptosis in tumor cells. We investigated the mechanisms by which COX-2 inhibition induces apoptosis in hepatocellular carcinoma (HCC) cells. COX-2 inhibition triggered expression of the CD95, tumor necrosis factor (TNF)-R, and TNF-related apoptosis-inducing ligand (TRAIL)-R1 and TRAIL-R2 death receptors. Addition of the respective specific ligands further increased apoptosis, indicating that COX-2 inhibition induced the expression of functional death receptors. Overexpression of a dominant-negative Fas-associated death domain mutant reduced COX-2 inhibitor-mediated apoptosis. Furthermore, our findings showed a link between COX-2 inhibition and the mitochondrial apoptosis pathway. COX-2 inhibition led to a rapid down-regulation of myeloid cell leukemia-1 (Mcl-1), an antiapoptotic member of the Bcl-2 family, followed by translocation of Bax to mitochondria and cytochrome c release from mitochondria. Consequently, overexpression of Mcl-1 led to inhibition of COX-2 inhibitormediated apoptosis. Furthermore, blocking endogenous Mcl-1 function using a small-interfering RNA approach enhanced COX-2 inhibitor-mediated apoptosis. It is of clinical importance that celecoxib acted synergistically with chemotherapeutic drugs in the induction of apoptosis in HCC cells. The clinical relevance of these results is further substantiated by the finding that COX-2 inhibitors did not sensitize primary human hepatocytes toward chemotherapy-induced apoptosis. In conclusion, COX-2 inhibition engages different apoptosis pathways in HCC cells stimulating death receptor signaling, activation of caspases, and apoptosis originating from mitochondria. (Cancer Res 2006; 66(14): 7059-66)

The beneficial effect of non-hypotensive doses of alpha and beta blockers and their combination on renal morphology and albuminuria in the model of renal ablation argue for a blood pressure-independent role of sympathetic overactivity in the genesis of progression. In addition, the beneficial effect of adrenergic receptor blockade indicates that a substantial part is not mediated by sympathetic cotransmitters such as adenosine 5'-triphosphate (ATP) and neuropeptide Y (NPY).

We investigated the downstream mechanisms by which chemotherapeutic drugs elicit apoptosis in hepatocellular carcinoma (HCC). Genomic signatures of HCC cell lines treated with different chemotherapeutic drugs were obtained. Analyses of apoptosis pathways were performed and RNA interference was used to evaluate the role of the p53 family. Endogenous p53, p63 and p73 were upregulated in response to DNA damage by chemotherapeutic drugs. Blocking p53 family function led to chemoresistance in HCC. Stimulation and blocking experiments of the CD95-, the TNF-and the TRAIL-receptor systems revealed that cytotoxic drugs, via the p53 family members as transactivators, can trigger expression of each of these death receptors and consequently sensitize HCC cells toward apoptosis. Furthermore, our findings demonstrate a link between chemotherapy, the p53 family and the mitochondrial apoptosis pathway in HCC. Chemotherapeutic treatment induces expression of proapoptotic Bcl-2 family members like Bax and BCL2L11 and the expression of Apaf1, BNIP1, Pdcd8 and RAD. Thus, upon DNA damage, p53, p63 and p73 promote apoptosis via the extrinsic and the intrinsic signaling pathway. In addition, not only proapoptotic genes were upregulated, but also genes known to exert antiapoptotic functions. Bleomycininduced upregulation of BCL-XL/BCLXL1 and MDM2 suggests that it is the ratio of proapoptotic and antiapoptotic proteins that regulates the apoptosis response of HCC cells toward chemotherapy, thereby playing a decisive role between treatment sensitivity vs. drug resistance. The clinical importance of these data is evidenced by our finding that the bleomycin target gene signature can predict the prognosis of patients suffering from HCC.Inactivation of tumor suppressor genes or activation of protooncogenes can lead to clonal outgrowth and tumor progression. These oncogenic events evolve as important determinants in the response of human tumors to commonly used DNA damaging agents. 1 Many anticancer agents induce DNA damage as part of their mechanism of tumor cytotoxicity. DNA damage activates p53, which in turn induces the expression of proteins that halt the cell-division cycle to allow for DNA repair. 2,3 Activation of p53 can also initiate programs of cell death (apoptosis) or permanent growth arrest (senescence) if the DNA damage is severe. [4][5][6][7][8][9][10][11][12][13] Furthermore, the recent identification and characterization of the p53/p63/p73 network provides evidence of a tight link between developmental processes and tumorigenesis. 14-16 p63 and p73 are not only important for normal development and differentiation, but are also implicated in tumorigenesis and the response to chemo-or radiotherapies. [17][18][19][20] The p53 family genes, p53, p63 and p73, produce multiple isoforms that vary in composition of the NH 2 -and C-termini. Isoforms of the p53 family can interact with each other and form a complicated network. The dominant-negative (DN) isoforms can oppose the transactivation capabilities of the full length (TA) prot...