Estrogen-dependent MicroRNA-504 Expression and Related Baroreflex Afferent Neuroexcitation via Negative Regulation on KCNMB4 and KCa1.1 ß4-subunit Expression.

Large conductance of Ca2+-activated K+ channel (KCa1.1) plays an inhibitory role in neuroexcitation. However, the expression of KCNMB4/ß4-subunit in the nodose ganglia (NG) and nucleus tractus solitarius (NTS), and its effect and regulation on baroreflex afferent function at post-transcriptional level of female rats remains unknown. Here, we demonstrated that the expression of ß4-subunit encoded by KCNMB4 was significantly lower in females vs. males and ovariectomized (OVX) rats in the NG. Although all baroreceptor neurons (BRNs) expressed ß4-subunit, altered discharge characteristics were only observed in Ah-type neurons after ovariectomy. Notably, the decreased excitability of Ah-types was restored by paxilline and further enhanced by iberiotoxin. The consistent changes were observed in excitatory post-synaptic currents. The level of miR-504 was higher in females, which was predicted to bind to the 3'UTR of KCNMB4. In consistent, an inverse expression pattern between miR-504 and KCNMB4 was observed in baroreflex afferents. The paxilline-sensitive ß4-subunits is less in Ah-types and up-regulated by ovariectomy. These data indicated that KCa1.1 ß4-subunit is the key regulator in neuroexcitation of Ah-types and sexual-dimorphism in baroreflex afferent function through estrogen-dependent inhibition of KCNMB4 expression via miR-504.

[Analysis of Correlation between Gene Mutation and Age in Patients with MDS and MDS/AML].

OBJECTIVE: To study the correlation between tumor-associated somatic gene mutation and age in patients with myelodysplastic syndromes (MDS) and acute myeloid leukemia transformed from myelodysplastic syndrome (MDS/AML). METHODS: A total of 111 patients primarily diagnosed as MDS or MDS/AML were selected. Bone marrow samples from patients were collected or bone marrow smears prepared at the initial diagnosis were used for detecting the somatic gene mutations of 58 genes related with hematologic tumors by high-throughput gene sequencing. And the correlation of gene mutations with the age of patients was analyzed. RESULTS: The positive rate of total gene mutation was 87.39% (97/111) in 111 patients, and 231 mutations in 28 different genes were detected in the patients with positive gene mutation. The patients of mutation-positive group were significantly older than that of the mutation-negative group (P＜0.001). Among the mutation-positive patients, the mutation rate in the senile group (≥60 years) was 100% (14/14), followed by 89.04% (74/85) in the adult group (15-59 years) and 75% (9/12) in the children group (≤14 years). The average number of mutations in the children group, the adult group and the senile group were respectively 1.44, 2.47 and 2.5; the number of mutations in the adult group was greater than that in the children group (P＜0.05).The most common mutations in the children group occurred in signal transduction gene (46.15%, 6/13); The most common mutations in both the adult group (22.40%, 41/183) and the senile group (34.29%, 12/35) occurred in epigenetic regulatory gene; the mutation rate of transcription factor gene in the senile group was higher than that in the children group (50.00% vs 8.33%) (P＜0.05); the mutation rates of the splicing factor gene in the adult group and the senile group were higher than that in the children group (44.71% vs 8.33%) (P＜0.05), (47.06% vs 8.33%) (P＜0.05). CONCLUSION: The tumor-associated somatic gene mutations in patients with MDS and MDS/AML are significantly different between the different age groups, especially the children group and the adults group as well as the senile group, suggesting that the occurrence of MDS in children may involve genetic factors that are significantly different from those of adults and the senile.

Increase in neuroexcitability of unmyelinated C-type vagal ganglion neurons during initial postnatal development of visceral afferent reflex functions.

BACKGROUND: Baroreflex gain increase up closely to adult level during initial postnatal weeks, and any interruption within this period will increase the risk of cardiovascular problems in later of life span. We hypothesize that this short period after birth might be critical for postnatal development of vagal ganglion neurons (VGNs). METHODS: To evaluate neuroexcitability evidenced by discharge profiles and coordinate changes, ion currents were collected from identified A- and C-type VGNs at different developmental stages using whole-cell patch clamping. RESULTS: C-type VGNs underwent significant age-dependent transition from single action potential (AP) to repetitive discharge. The coordinate changes between TTX-S and TTX-R Na(+) currents were also confirmed and well simulated by computer modeling. Although 4-AP or iberiotoxin age dependently increased firing frequency, AP duration was prolonged in an opposite fashion, which paralleled well with postnatal changes in 4-AP- and iberiotoxin-sensitive K(+) current activity, whereas less developmental changes were verified in A-types. CONCLUSION: These data demonstrate for the first time that the neuroexcitability of C-type VGNs increases significantly compared with A-types within initial postnatal weeks evidenced by AP discharge profiles and coordinate ion channel changes, which explain, at least in part, that initial postnatal weeks may be crucial for ontogenesis in visceral afferent reflex function.