Upregulated Kynurenine Pathway Enzymes in Aortic Atherosclerotic Aneurysm: Macrophage Kynureninase Downregulates Inflammation.

AIMS: Inflammation and hypertension contribute to the progression of atherosclerotic aneurysm in the aorta. Vascular cell metabolism is regarded to modulate atherogenesis, but the metabolic alterations that occur in atherosclerotic aneurysm remain unknown. The present study aimed to identify metabolic pathways and metabolites in aneurysmal walls and examine their roles in atherogenesis. METHODS: Gene expression using microarray and metabolite levels in the early atherosclerotic lesions and aneurysmal walls obtained from 42 patients undergoing aortic surgery were investigated (early lesion n=11, aneurysm n=35) and capillary electrophoresis-time-of-flight mass spectrometry (early lesion n=14, aneurysm n=38). Using immunohistochemistry, the protein expression and localization of the identified factors were examined (early lesion n=11, non-aneurysmal advanced lesion n=8, aneurysm n=11). The roles of the factors in atherogenesis were analyzed in macrophages derived from human peripheral blood mononuclear cells. RESULTS: Enrichment analysis using 35 significantly upregulated genes (log2 ratio, ＞3) revealed the alteration of the kynurenine pathway. Metabolite levels of tryptophan, kynurenine, and quinolinic acid and the kynurenine-to-tryptophan ratio were increased in the aneurysmal walls. Gene and protein expression of kynureninase and kynurenine 3-monooxygenase were upregulated and localized in macrophages in the aneurysmal walls. The silencing of kynureninase in the cultured macrophages enhanced the expression of interleukin-6 and indoleamine 2,3-dioxygenase 1. CONCLUSION: Our study suggests the upregulation of the kynurenine pathway in macrophages in aortic atherosclerotic aneurysm. Kynureninase may negatively regulate inflammation via the kynurenine pathway itself in macrophages.

Identification of a novel human gene, ZFP91, involved in acute myelogenous leukemia.

To elucidate mechanisms leading to acute myelogenous leukemia (AML), to find sensitive markers and novel targets for drug therapy, and to allow choice of suitable chemotherapy for each affected individual, we previously compared expression of mRNA from mononuclear cells of AML patients with that of normal controls using a cDNA microarray. Data from that study identified many genes that were commonly up- or down-regulated in AML cells. Of these, we report here the identification of a novel gene whose expression was increased in 27 (93%) of the 29 AML cases whose PBMC preparations include >70% leukemia cells. The gene product, localized in nuclei, showed several characteristics of transcription factors: five zinc-finger domains, a leucine zipper, and several nuclear localization signals. Its 92.5% identity in amino-acid sequence to the murine penta zinc finger protein (mPZf; gene symbol Zfp91), led us to term it ZFP91. Anti-sense oligonucleotides inhibited expression of ZFP91, suppressed cell growth, and induced apoptosis. Our results suggest that ZFP91 is likely to play an important role in cell proliferation and/or anti-apoptosis, and may serve as a molecular marker for AML.

Jun dimerization protein 2 (JDP2), a member of the AP-1 family of transcription factor, mediates osteoclast differentiation induced by RANKL.

Osteoclasts are multinucleated cells that resorb bones, and are derived from hematopoietic cells of the monocyte/macrophage lineage. The receptor activator of NF-kappaB ligand (RANKL, also called ODF/TRANCE/OPGL) stimulates both osteoclast differentiation from osteoclast progenitors and activation of mature osteoclasts. To identify genes responsible for osteoclast differentiation, we used a molecular indexing technique. Here, we report a clone of one of these genes whose transcription is induced by soluble RANKL (sRANKL) in both the RAW264.7 cells of the mouse macrophage cell line and the mouse primary bone marrow cells. The predicted protein was found to be a mouse homologue of Jun dimerization protein 2 (JDP2), a member of the AP-1 family of transcription factors, containing a basic region-leucine zipper motif. Transient transfection experiments revealed that overexpression of JDP2 leads to activation of both tartrate-resistant acid phosphatase (TRAP) and cathepsin K gene promoters in RAW264.7 cells. Infection of mouse primary bone marrow cells with retroviruses expressing JDP2-facilitated sRANKL-mediated formation of TRAP-positive multinuclear osteoclasts. Importantly, antisense oligonucleotide to JDP2 strongly suppressed sRANKL-induced osteoclast formation of RAW264.7 cells. Our findings suggest that JDP2 may play an important role in the RANK-mediated signal transduction system, especially in osteoclast differentiation.

Prediction of chemosensitivity for patients with acute myeloid leukemia, according to expression levels of 28 genes selected by genome-wide complementary DNA microarray analysis.

To identify genes involved in the sensitivity of acute myeloid leukemia (AML) cells to chemotherapy, we monitored gene-expression profiles of cancer cells from 76 AML patients using a cDNA microarray consisting of 23,040 genes. We identified 63 genes that were commonly overexpressed and 372 genes suppressed in AML. Because these genes represent key molecules for disclosing the molecular mechanisms of AML, they may be potential targets for drug development. We also found 28 that revealed different expression levels between good and poor responders to chemotherapy and appeared to be associated with chemosensitivity. On that basis, we developed a "Drug Response Scoring" system that was correlated well with individual sensitivity to an anticancer drug regimen. Among the 44 cases with positive drug-response scores by our definition, 40 achieved complete remission after treatment, whereas the only 3 of the 20 cases with negative scores responded well to the treatment. An ability to predict chemosensitivity should eventually lead to achievement of our goal of "personalized therapy."