Nitric oxide regulates homeoprotein OTX1 and OTX2 expression in the rat myenteric plexus after intestinal ischemia-reperfusion injury.

Neuronal and inducible nitric oxide synthase (nNOS and iNOS) play a protective and damaging role, respectively, on the intestinal neuromuscular function after ischemia-reperfusion (I/R) injury. To uncover the molecular pathways underlying this dichotomy we investigated their possible correlation with the orthodenticle homeobox proteins OTX1 and OTX2 in the rat small intestine myenteric plexus after in vivo I/R. Homeobox genes are fundamental for the regulation of the gut wall homeostasis both during development and in pathological conditions (inflammation, cancer). I/R injury was induced by temporary clamping the superior mesenteric artery under anesthesia, followed by 24 and 48 h of reperfusion. At 48 h after I/R intestinal transit decreased and was further reduced by Nω-propyl-l-arginine hydrochloride (NPLA), a nNOS-selective inhibitor. By contrast this parameter was restored to control values by 1400W, an iNOS-selective inhibitor. In longitudinal muscle myenteric plexus (LMMP) preparations, iNOS, OTX1, and OTX2 mRNA and protein levels increased at 24 and 48 h after I/R. At both time periods, the number of iNOS- and OTX-immunopositive myenteric neurons increased. nNOS mRNA, protein levels, and neurons were unchanged. In LMMPs, OTX1 and OTX2 mRNA and protein upregulation was reduced by 1400W and NPLA, respectively. In myenteric ganglia, OTX1 and OTX2 staining was superimposed with that of iNOS and nNOS, respectively. Thus in myenteric ganglia iNOS- and nNOS-derived NO may promote OTX1 and OTX2 upregulation, respectively. We hypothesize that the neurodamaging and neuroprotective roles of iNOS and nNOS during I/R injury in the gut may involve corresponding activation of molecular pathways downstream of OTX1 and OTX2.NEW & NOTEWORTHY Intestinal ischemia-reperfusion (I/R) injury induces relevant alterations in myenteric neurons leading to dismotility. Nitrergic neurons seem to be selectively involved. In the present study the inference that both neuronal and inducible nitric oxide synthase (nNOS and iNOS) expressing myenteric neurons may undergo important changes sustaining derangements of motor function is reinforced. In addition, we provide data to suggest that NO produced by iNOS and nNOS regulates the expression of the vital transcription factors orthodenticle homeobox protein 1 and 2 during an I/R damage.

Identification of OTX1 and OTX2 As Two Possible Molecular Markers for Sinonasal Carcinomas and Olfactory Neuroblastomas.

OTX homeobox (HB) genes are expressed during embryonic morphogenesis and during the development of olfactory epithelium in adult organisms. Mutations occurring in these genes are often related to tumorigenesis in human. No data are available today regarding the possible correlation between OTX genes and tumors of the nasal cavity. The aim of this work is to understand if OTX1 and OTX2 can be considered as molecular markers in the development of nasal tumors. We selected nasal and sinonasal adenocarcinomas to investigate the expression of OTX1 and OTX2 genes through immunohistochemical and real-time PCR analyses.Both OTX1 and OTX2 were absent in all the samples of sinonasal Intestinal-Type Adenocarcinomas (ITACs). OTX1 mRNA was identified only in Non-Intestinal Type Adenocarcinomas (NITACs) while OTX2 mRNA was expressed only in Olfactory Neuroblastomas (ONs). We have demonstrated that the differential gene expression for both OTX1 and OTX2 genes might be a useful molecular marker to distinguish the different types of sinonasal tumors.

gDNA qPCR is statistically more reliable than mRNA analysis in detecting leukemic cells to monitor CML.

Chronic Myeloid Leukemia (CML) is a stem cell cancer that arises when t(9;22) translocation occurs in a hematopoietic stem cells. This event results in the expression of the BCR-ABL1 fusion gene, which codes for a constitutively active tyrosine kinase that is responsible for the transformation of a HSC into a CML stem cell, which then gives rise to a clonal myeloproliferative disease. The introduction of Tyrosine Kinase Inhibitors (TKIs) has revolutionized the management of the disease. However, these drugs do not seem to be able to eradicate the malignancy. Indeed, discontinuation trials (STIM; TWISER; DADI) for those patients who achieved a profound molecular response showed 50% relapsing within 12 months. We performed a comparative analysis on 15 CML patients and one B-ALL patient, between the standard quantitative reverse-transcriptase PCR (qRT-PCR) and our genomic DNA patient-specific quantitative PCR assay (gDNA qPCR). Here we demonstrate that gDNA qPCR is better than standard qRT-PCR in disease monitoring after an average follow-up period of 200 days. Specifically, we statistically demonstrated that DNA negativity is more reliable than RNA negativity in indicating when TKIs therapy can be safely stopped.

OTX1 and OTX2 as possible molecular markers of sinonasal carcinomas and olfactory neuroblastomas.

OTX Homeobox genes are involved in embryonic morphogenesis and in the development of olfactory epithelium in adult. Mutations occurring in the OTX genes are reported to be associated to tumorigenisis in human. No reports correlate the expression of OTX genes and neoplasms of the nasal cavity. Thus, through immunohistochemical and Real-time PCR analysis we investigated OTX1 and OTX2 expression in the more frequent types of nasal and sinonasal tumours. Variable expression of both genes were found in normal sinonasal mucosa and in tumours. Interestingly, no expression of both OTX genes were detected in sinonasal intestinal-type adenocarcinomas; only OTX1 was found in non-intestinal-type adenocarcinomas and OTX2 was selectively expressed in olfactory neuroblastomas. In conclusion, OTX1 and OTX2 genes might have a role in the pathogenesis of different types of sinonasal neoplasms.