QUANTITATIVE MORPHOLOGICAL AND MOLECULAR PATHOLOGY OF THE HUMAN THYMUS CORRELATE WITH INFANT CAUSE OF DEATH.

The objective of this study was to investigate and quantify the morphological and molecular changes in the thymus for common causes of human infant death. Thymic architecture and molecular changes apparent in human infant head trauma victims were assessed by microscopy and quantified by image analysis of digital whole slide images. Thymuses from victims of SIDS and suffocated infants displaying normal thymus architecture were used for comparison.

Mechanism of resistance to dietary cholesterol.

Background. Alterations in expression of hepatic genes that could contribute to resistance to dietary cholesterol were investigated in Sprague-Dawley rats, which are known to be resistant to the serum cholesterol raising action of dietary cholesterol. Methods.

Thyroid hormone enhances the ability of serum to accept cellular cholesterol via the ABCA1 transporter.

Objective: The goal of this study was to examine the effects of thyroid hormone status on the ability of serum to accept cellular cholesterol.

Methods And Results: Sera from hypophysectomized rats treated ± T(3) was used to evaluate the role of thyroid hormone on serum efflux capacity. 2D-DIGE analysis of serum proteins showed that T(3) treated rats had increased ApoA-I, ApoA-IV and fetuin A levels with decreased Apo E levels.

Peroxisome proliferator activated receptor alpha (PPARalpha) and PPAR gamma coactivator (PGC-1alpha) induce carnitine palmitoyltransferase IA (CPT-1A) via independent gene elements.

Long chain fatty acids and pharmacologic ligands for the peroxisome proliferator activated receptor alpha (PPARalpha) activate expression of genes involved in fatty acid and glucose oxidation including carnitine palmitoyltransferase-1A (CPT-1A) and pyruvate dehydrogenase kinase 4 (PDK4). CPT-1A catalyzes the transfer of long chain fatty acids from acyl-CoA to carnitine for translocation across the mitochondrial membranes and is an initiating step in the mitochondrial oxidation of long chain fatty acids. PDK4 phosphorylates and inhibits the pyruvate dehydrogenase complex (PDC) which catalyzes the conversion of pyruvate to acetyl-CoA in the glucose oxidation pathway.

In vivo identification of promoter elements and transcription factors mediating activation of hepatic HMG-CoA reductase by T3.

The promoter elements and transcription factors necessary for triiodothyronine (T3) induction of hepatic HMG-CoA reductase (HMGR) were investigated by transfecting rat livers with wild type and mutant HMGR promoter-luciferase constructs using in vivo electroporation. Mutations in the sterol response element (SRE), nuclear factor-y (NF-Y) site, and the newly identified upstream transcription factor-2 (USF-2) site essentially abolished the T3 response. Chromatin immunoprecipitation (ChIP) analysis demonstrated that T(3) treatment caused a 4-fold increase in in vivo binding of USF-2 to the HMGR promoter.

Technological advances in the study of HLA-DRA promoter regulation: extending the functions of CIITA, Oct-1, Rb, and RFX.

Several advances were established in examining the interaction of transcriptional factors with the HLA-DRA promoter. First, hydrodynamic injection was used to demonstrate the activation of the promoter by class II transactivator in a live mouse. Second, the Oct-1 DNA-binding site in the HLA-DRA promoter is a negative element in many cells, but here we show that Oct-1 activates the promoter independently of the Oct-1-binding site.

Rescue of major histocompatibility-DR surface expression in retinoblastoma-defective, non-small cell lung carcinoma cells by the MS-275 histone deacetylase inhibitor.

Major histocompatibility (MHC) class II expression is ordinarily inducible by interferon-gamma (IFN-gamma), but the induction is repressed in retinoblastoma protein (Rb)-defective cells. The repression can be rescued by histone deacetylase (HDAC) inhibitor treatment, but this has never been shown for an HDAC inhibitor that is suitable for clinical trials and eventual patient therapy. Here we demonstrate that the HDAC inhibitor, MS-275, can rescue the IFN-gamma inducibility of human leukocyte antigen (HLA)-DR in non-small cell lung cancer cells.

Linkage of a tumor immune function and cell cycle de-regulation via a gene regulatory network subcircuit.

Gene regulatory network (GRN) subcircuits have been described for cell fate progressions in animal development. The hallmark of these subcircuits is the integration of promoters, and positive- and negative-acting promoter binding proteins, such that an alteration in function of any one member of the defined subcircuit, occurring with a change in cell fate, defines a change in status for all other members of the subcircuit. Here we describe a GRN subcircuit that links a tumor immune function with cell cycle de-regulation.

A direct mechanistic link between growth control and a tumor cell immune function: increased interleukin-8 secretion accounts for elimination of Oct-1 antisense transformants from scid mice.

Background: Tumorigenesis involves the aberrant function of proteins that regulate growth control, including Oct-1. Oct-1 is a DNA binding transcription factor that activates genes that encode proteins required for S-phase and cell growth. For example, Oct-1 activates the histone H2B promoter and the promoters for the snRNPs.

Activation of a methylated promoter mediated by a sequence-specific DNA-binding protein, RFX.

The roles of eukaryotic DNA methylation in the repression of mRNA transcription and in the formation of heterochromatin have been extensively elucidated over the past several years. However, the role of DNA methylation in transcriptional activation remains a mystery. In particular, it is not known whether the transcriptional activation of methylated DNA is promoter-specific, depends directly on sequence-specific DNA-binding proteins, or is facilitated by the methylation.

Oct-1 maintains an intermediate, stable state of HLA-DRA promoter repression in Rb-defective cells: an Oct-1-containing repressosome that prevents NF-Y binding to the HLA-DRA promoter.

The cell surface HLA-DR molecule binds foreign peptide antigen and forms an intercellular complex with the T cell receptor in the course of the development of an immune response against or immune tolerance to the antigen represented by the bound peptide. The HLA-DR molecule also functions as a receptor that mediates cell signaling pathways, including as yet poorly characterized pathway(s) leading to apoptosis. Expression of HLA-DR mRNA and protein is ordinarily inducible by interferon-gamma but is not inducible in tumor cells defective for the retinoblastoma tumor suppressor protein (Rb).