Host susceptibility to severe influenza A virus infection.

Most people exposed to a new flu virus do not notice any symptoms. A small minority develops critical illness. Some of this extremely broad variation in susceptibility is explained by the size of the initial inoculum or the influenza exposure history of the individual; some is explained by generic host factors, such as frailty, that decrease resilience following any systemic insult. Some demographic factors (pregnancy, obesity, and advanced age) appear to confer a more specific susceptibility to severe illness following infection with influenza viruses. As with other infectious diseases, a substantial component of susceptibility is determined by host genetics. Several genetic susceptibility variants have now been reported with varying levels of evidence. Susceptible hosts may have impaired intracellular controls of viral replication (e.g. IFITM3, TMPRS22 variants), defective interferon responses (e.g. GLDC, IRF7/9 variants), or defects in cell-mediated immunity with increased baseline levels of systemic inflammation (obesity, pregnancy, advanced age). These mechanisms may explain the prolonged viral replication reported in critically ill patients with influenza: patients with life-threatening disease are, by definition, abnormal hosts. Understanding these molecular mechanisms of susceptibility may in the future enable the design of host-directed therapies to promote resilience.

Distinct developmental origins and regulatory mechanisms for GABAergic neurons associated with dopaminergic nuclei in the ventral mesodiencephalic region.

GABAergic neurons in the ventral mesodiencephalic region are highly important for the function of dopaminergic pathways that regulate multiple aspects of behavior. However, development of these neurons is poorly understood. We recently showed that molecular regulation of differentiation of the GABAergic neurons associated with the dopaminergic nuclei in the ventral midbrain (VTA and SNpr) is distinct from the rest of midbrain, but the reason for this difference remained elusive. Here, we have analyzed the developmental origin of the VTA and SNpr GABAergic neurons by genetic fate mapping. We demonstrate that the majority of these GABAergic neurons originate outside the midbrain, from rhombomere 1, and move into the ventral midbrain only as postmitotic neuronal precursors. We further show that Gata2, Gata3 and Tal1 define a subpopulation of GABAergic precursors in ventral rhombomere 1. A failure in GABAergic neuron differentiation in this region correlates with loss of VTA and SNpr GABAergic neurons in Tal1 mutant mice. In contrast to midbrain, GABAergic neurons of the anterior SNpr in the diencephalon are not derived from the rhombomere 1. These results suggest unique migratory pathways for the precursors of important GABAergic neuron subpopulations, and provide the basis for understanding diversity within midbrain GABAergic neurons.

GATA factors in human neuroblastoma: distinctive expression patterns in clinical subtypes.

BACKGROUND: The aim of this study is to elucidate the expression patterns of GATA transcription factors in neuroblastoma and the developing sympathetic nervous system (SNS). METHODS: GATA-2, -3 and -4 and their cofactor friend-of-GATA (FOG)-2 were investigated in primary neuroblastoma by immunohistochemistry, real-time RT-PCR (n=73) and microarray analysis (n=251). In addition, GATA-2, -3 and FOG-2 expression was determined by northern-blot hybridisation. In the developing murine SNS, Gata-4 and Fog-2 were examined by immunohistochemistry. RESULTS: Although Gata-2, -3 and Fog-2 are expressed in the developing nervous system, Gata-4 was not detected. In contrast, protein expression of all factors was observed in human neuroblastoma. Northern-blot hybridisation and real-time RT-PCR suggested specific expression patterns of the four genes in primary neuroblastoma, but did not show unequivocal results. In the large cohort examined by microarrays, a significant association of GATA-2, -3 and FOG-2 expression with low-risk features was observed, whereas GATA-4 mRNA levels correlated with MYCN-amplification. CONCLUSION: The transcription factors GATA-2 and -3, which are essential for normal SNS development, and their cofactor FOG-2 are downregulated in aggressive but not in favourable neuroblastoma. In contrast, upregulation of GATA-4 appears to be a common feature of this malignancy and might contribute to neuroblastoma pathogenesis.

Clinical significance of Gata-1, Gata-2, EKLF, and c-MPL expression in acute myeloid leukemia.

The aim of this study was to evaluate the biological correlation and prognostic impact of Gata-1, Gata-2, EKLF, and c-MPL transcript level in a group of 41 acute myeloid leukemia (AML) patients. Gata-1 overexpression was related to advanced age and a low percentage of bone marrow blasts and was associated with the expression of CD34 antigen and lymphoid T markers. The negative impact of Gata-1 expression on the probability of achieving complete remission has been confirmed. Gata-2 overexpression was associated with a low percentage of blasts in BM and males. Expression of c-MPL was associated with CD34+ AML and M2 FAB AML subtype. A higher expression of EKLF was found in secondary AML versus primary AML. Nevertheless, patients expressing EKLF had a longer overall survival and event free survival than those patients that did not express EKLF. Our study has identified expression of EKLF as a factor with a favorable impact on prognosis in AML.

A comparison of inflammatory mediators released by basophils of asthmatic and control subjects in response to high-affinity IgE receptor aggregation.

BACKGROUND: In human blood basophils, cross-linking the high-affinity IgE receptor Fc epsilonRI with multivalent antigen activates a signaling pathway leading to secretion of inflammatory mediators and cytokine production. Basophils are known to play an important role in the pathogenesis of asthma but there has been no comprehensive examination of the effectors these cells produce. Here a study of the transcription and release of a selection of chemokines and cytokines from basophils was undertaken. METHODS: A Cartesian antibody array provided an effective method of assaying for multiple cytokines and chemokines simultaneously. Results were verified by RT-PCR and ELISA assays. This allowed the comparison of freshly prepared peripheral blood basophil responses to cross-linking of the high-affinity IgE receptor, with and without preincubation with IL-3. RESULTS: Evidence that human blood basophils produce the chemokines MIP-5, eotaxin and GM-CSF was provided by antibody array and RT-PCR analyses. Preincubation with IL-3 enhanced the expression and release of IL-13, IL-8 and mRNA transcripts encoding MIP-5 and GATA2 in basophils from both asthmatic and control subjects. Leptin mRNA transcription, storage and release in basophils are described for the first time. CONCLUSIONS: Surveying cytokine and chemokines stored and released by peripheral blood basophils shows that asthmatic and control subjects share similar profiles even when their degranulation responses are distinct. Evidence is provided for the production of leptin, GM-CSF, eotaxin and MIP-5 by peripheral blood basophils. IL-3 preincubation enhances the production and release of IL-8 upon IgE receptor cross-linking.

Upregulation of gingival tissue miR-200b in obese periodontitis subjects.

Increased local immune and inflammatory responses in obese individuals with periodontitis may explain the aggressive clinical presentation and altered treatment response when compared to that of normal weight subjects. Our goal was to identify any differences in microRNA (miRNA) expression profiles of gingival tissue in periodontitis when obesity is present, which may suggest novel molecular pathways that this miRNA network may affect. Total RNA was extracted from gingival tissue biopsies collected from normal weight and obese individuals with periodontitis; miRNA expression profiling was performed with Affymetrix GeneChip miRNA 3.0 arrays; and results were validated with quantitative reverse transcription polymerase chain reaction (qRT-PCR). In silico identification of previously confirmed miRNA gene targets was conducted through miRTarBase and miRWalk databases, and pathway enrichment analysis identified enriched miRNA gene sets. Expression of selected genes in the same biopsy samples was tested with qRT-PCR. The gingival tissue miRNA profile of obese patients, compared to that of normal weight patients, showed 13 upregulated and 22 downregulated miRNAs, among which miR-200b was validated by qRT-PCR to be significantly increased in obesity. Functional analysis of 51 experimentally validated miR-200b gene targets identified enrichment of genes involved in cell motility, differentiation, DNA binding, response to stimulus, and vasculature development pathways not previously identified in the obesity-specific disease profile. Furthermore, the expression of the miR-200b gene targets ZEB1/2, GATA2, and KDR was confirmed by qRT-PCR as being lower in obese patients with periodontitis versus normal weight patients, suggesting a role of miR-200b in regulation of a set of gene targets and biological pathways relevant to wound healing and angiogenesis. Functional studies to explore the role of miR-200b in the above processes may offer new insights on putative therapeutic targets for this group of patients.

Elevated TIM3+ hematopoietic stem cells in untreated myelodysplastic syndrome displayed aberrant differentiation, overproliferation and decreased apoptosis.

TIM3, as a negative regulator of anti-tumor immunity, is highly expressed on LSCs, but not on normal HSCs. TIM3 on HSCs in MDS patients has not been clarified. Here, both the percentage of TIM3 on HSCs and the MFI of TIM3+ HSCs were higher in untreated MDS than control and were closed to AML, and excessive TIM3+ HSCs was closely related to clinical parameters: WPSS score, karyotype analysis, morphologic blasts, the number of cytopenia involving hematopoietic lineages, anemia and granulocytopenia. TIM3+ HSCs expressed lower CD11b, TpoR, EpoR, G-CSFR and Annexin V, and higher CD71 and GATA2. TIM3+ HSCs displayed aberrant differentiation, overproliferation and decreased apoptosis. TIM3 might be a promising marker for identifying malignant clone cells in MDS and a candidate for targeted therapy.

A role for GATA-2 in transition to an aggressive phenotype in prostate cancer through modulation of key androgen-regulated genes.

GATA-2, a member of the GATA family of transcription factors, is involved in androgen receptor (AR) signaling, however, little is known regarding its role in prostate cancer. Here, we report that GATA-2 is expressed in a substantial proportion of prostate cancers and that high expression of GATA-2 is associated with biochemical recurrence and distant metastatic progression in a validation set of 203 cancers. In vitro data show that GATA-2 is directly recruited to the promoter region of the AR upon androgen stimulation of LNCaP prostate cancer cells with 5alpha-dihydroxytestosterone (DHT) for 24 h. Ectopic GATA-2 expression causes the induction of AR transcript levels under androgen-depleted conditions (P<0.05). The expression of the AR target gene, AZGP1, is induced upon androgen stimulation and this effect is repressed by GATA-2. In contrast, GATA-2 significantly increases transcript levels of KLK2, which increases further in a time-dependent manner on DHT treatment and in the presence of GATA-2. These results indicate that upregulation of GATA-2 may contribute to the progression to aggressive prostate cancer through modulation of expression of AR and key androgen-regulated genes, one of which, AZGP1, is associated with the progression to metastatic disease.

Clinicopathological characterization of TSH-producing adenomas: special reference to TSH-immunoreactive but clinically non-functioning adenomas.

Thyrotropin (thyroid-stimulating hormone (TSH))-producing pituitary adenomas have been known to be quite variable in clinical features covering from typical functioning TSH-producing adenomas (FTSHomas) associated with hyperthyroidism to clinically silent TSH cell adenomas (STAs) that are apparently unassociated with hyperthyroidism. It is important to distinguish STAs from other types of clinically non-functioning adenomas for adequate postoperative managements. However, because of rareness of TSH-producing adenomas, their histopathological features linking to the clinical manifestations have not been well characterized. Herein, we investigated clinical and histopathological findings to characterize 29 TSH-producing adenomas including 20 FTSHomas and nine STAs. Clinical symptoms of the patients with STAs included headache, visual defect, vertigo, and nausea. All STAs and 19 FTSHomas were macroadenoma. The average tumor size of STAs was significantly larger than that of FTSHomas (P < 0.05). The invasiveness was detected in 33% STAs and in 20% FTSHomas. Both STAs and FTSHomas showed a variety of morphological features and immunohistochemical profiles. Chromophobic polygonal or short-spindled tumor cells usually proliferated in a diffuse pattern, while they exhibited globoid or whorl-like appearance with intertwined cytoplasmic processes in both subgroups. Stromal fibrosis and calcification were often noted. Their nuclei were somehow pleomorphic. Ultrastructural features of all four STAs examined were similar to those of normal thyrotrophs. Thus, STAs and FTSHomas were indistinguishable by histology alone. Immunohistochemically, the number of TSH-positive cells in individual FTSHomas was highly various. Six tumors showed only a few TSH-positive cells (1-5%), and three were negative for TSH by conventional method without antigen retrieval. After proteinase K treatment, these tumors turned out TSH positive. As defined, STAs were TSH positive in more than 20% of tumor cells and three of them in more than 50%. Growth hormone- and/or prolactin-positive cells were detected in 55% STAs and 63% FTSHomas. Both pituitary-specific transcription factor 1 and GATA-binding protein 2 were expressed in all STAs and 20 FTSHomas. Membranous somatostatin receptor (SSTR)-2A immunoreactivity was found in 89% STAs and 94% FTSHomas, whereas SSTR5 was positive in 78% of both STAs and FTSHomas. MIB-1 labeling index was related to tumor invasiveness and tumor size (P < 0.05, P = 0.09, respectively). Thus, although both STAs and FTSHomas showed unique histopathological features distinct from other type adenomas, these two subgroups were indistinguishable by histopathology. Immunohistochemistry for TSH by use of antigen retrieval, transcription factors, and SSTRs may be useful to confirm STAs and to determine the postoperative therapy among various kinds of clinically non-functioning adenomas.