Invariant NKT Cells Act as an Adjuvant to Enhance Th2 Inflammatory Response in an OVA-Induced Mouse Model of Asthma

Background

Invariant natural killer T cells (iNKT cells) are a unique subset of T lymphocytes and are considered to play an important role in the development of allergic bronchial asthma. Recently, iNKT cells were shown to play an immunoregulatory role in CD4⁺ and CD8⁺ T cell-mediated adaptive immune response. Allergen-specific Th2 inflammatory responses are an important part of the adaptive immune response in asthma. However, the regulatory functions of the Th2 inflammatory response in asthma have not been studied in detail.

Method

In this study, we have investigated the regulatory functions of iNKT cells on the Th2 inflammatory response in an ovalbumin (OVA)-induced murine model of asthma.

Results

Our results demonstrate that α-Galactosylceramide (α-GalCer) administration activated iNKT cells but could not induce the Th2 inflammatory response in wild-type (WT) mice. In the OVA-induced asthma model, α-GalCer administration and adoptive transfer of iNKT cells significantly augmented the Th2 inflammatory responses, including elevated inflammatory cell infiltration in the lung and bronchoalveolar lavage fluid (BALF); increased levels of IL-4, IL-5, and IL-13 in the BALF and splenocyte culture supernatant; and increased serum levels of OVA-specific IgE and IgG1. In addition, the Th2 inflammatory response was reduced, but not completely abrogated in CD1d^-/- mice immunized and challenged with OVA, compared with WT mice.

Conclusion

These results suggest that iNKT cells may serve as an adjuvant to enhance Th2 inflammatory response in an OVA-induced murine model of asthma.     

Prevalence of Post-Stroke Cognitive Impairment in China: A Community-Based,Cross-Sectional Study

International hospital-based studies have indicated a high risk of cognitive impairment after stroke, evidence from community-based studies in China is scarce. To determine the prevalence of post-stroke cognitive impairment (PSCI) and its subtypes in stroke survivors residing in selected rural and urban Chinese communities, we conducted a community-based, cross-sectional study in 599 patients accounting for 48% of all stroke survivors registered in the 4 communities, who had suffered confirmed strokes and had undergone cognitive assessments via the Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), and Hachinski Ischemia Scale (HIS). Detection of PSCI was based on scores in these neuropsychological scales. Factors potentially impacting on occurrence of PSCI were explored by comparing demographic characteristics, stroke features, and cardiovascular risk factors between patients with and without PSCI. The overall prevalence of PSCI was 80.97% (95%CI: 77.82%-84.11%), while that of non-dementia PSCI (PSCI-ND) and post-stroke vascular dementia (PSD) was 48.91% (95%CI: 44.91%-52.92%) and 32.05% (95%CI: 28.32%-35.79%), respectively. Prior stroke and complications during the acute phase were independent risk factors for PSCI. The risk of recurrent stroke survivors having PSCI was 2.7 times higher than for first-episode survivors, and it was 3 times higher for those with complications during the acute phase than for those without. The higher prevalence of PSCI in this study compared with previous Chinese studies was possibly due to the combined effects of including rural stroke survivors, a longer period from stroke onset, and different assessment methods. There is an urgent need to recognize and prevent PSCI in stroke patients, especially those with recurrent stroke and complications during the acute phase.     

Climatic Factors Drive Population Divergence and Demography: Insights Based on the Phylogeography of a Riparian Plant Species Endemic to the Hengduan Mountains and Adjacent Regions

Quaternary climatic factors have played a significant role in population divergence and demography. Here we investigated the phylogeography of Osteomeles schwerinae, a dominant riparian plant species of the hot/warm-dry river valleys of the Hengduan Mountains (HDM), Qinling Mountains (QLM) and Yunnan-Guizhou Plateau (YGP). Three chloroplast DNA (cpDNA) regions (trnD-trnT, psbD-trnT, petL-psbE), one single copy nuclear gene (glyceraldehyde 3-phosphate dehydrogenase; G3pdh), and climatic data during the Last Interglacial (LIG; c. 120–140 ka), Last Glacial Maximum (LGM; c. 21 ka), and Current (c. 1950–2000) periods were used in this study. Six cpDNA haplotypes and 15 nuclear DNA (nDNA) haplotypes were identified in the 40 populations of O. schwerinae. Spatial Analysis of Molecular Variance, median-joining networks, and Bayesian phylogenetic trees based on the cpDNA and nDNA datasets, all suggested population divergence between the QLM and HDM-YGP regions. Our climatic analysis identified significant heterogeneity of the climatic factors in the QLM and HDM-YGP regions during the aforementioned three periods. The divergence times based on cpDNA and nDNA haplotypes were estimated to be 466.4–159.4 ka and 315.8–160.3 ka, respectively, which coincide with the time of the weakening of the Asian monsoons in these regions. In addition, unimodal pairwise mismatch distribution curves, expansion times, and Ecological Niche Modeling suggested a history of population expansion (rather than contraction) during the last glaciation. Interestingly, the expansion times were found being well consistent with the intensification of the Asian monsoons during this period. We inferred that the divergence between the two main lineages is probably caused by disruption of more continuous distribution because of weakening of monsoons/less precipitation, whilst subsequent intensification of the Asian monsoons during the last glaciation facilitated the expansion of O. schwerinae populations.     

Gender effects on trapezius surface EMG during delayed onset muscle soreness due to eccentric shoulder exercise.

The purpose of this study was to investigate gender-specific motor control strategies during eccentric exercise and delayed onset muscle soreness (DOMS) in the shoulder region. Twelve healthy males and females participated in the study. Eccentric shoulder exercises were conducted on the dominant shoulder while the other side served as control. The exerted force, range of shoulder elevation, rating of perceived exertion, pain intensity, and surface electromyography (EMG) from the trapezius muscles were recorded and analyzed. A significant decrease in exerted force during exercise was only found in males despite similar rating of perceived exertion among genders. During eccentric exercise: males showed increasing root mean square (RMS) of the EMG while a decrease occurred for females, no difference between genders in mean power frequency of the EMG were seen. During static and dynamic contractions: no differences between genders in pain intensity or RMS were observed; RMS of the exercised side were lower than that of the control side (P<0.05) at 24 h after exercise. The results indicated a more prominent muscle fatigue resistance in females compared with males and mobilization of different muscle activation strategies during eccentric exercise. A protective adaptation to DOMS, i.e. decrease in RMS values was found with no gender differences.     

Direct interaction of focal adhesion kinase with p190RhoGEF

Focal adhesion kinase (FAK) is a protein-tyrosine kinase that associates with multiple cell surface receptors and signaling proteins through which it can modulate the activity of several intracellular signaling pathways. FAK activity can influence the formation of distinct actin cytoskeletal structures such as lamellipodia and stress fibers in part through effects on small Rho GTPases, although the molecular interconnections of these events are not well defined. Here, we report that FAK interacts with p190RhoGEF, a RhoA-specific GDP/GTP exchange factor, in neuronal cells and in brain tissue extracts by co-immunoprecipitation and co-localization analyses. Using a two-hybrid assay and deletion mutagenesis, the binding site of the FAK C-terminal focal adhesion targeting (FAT) domain was identified within the C-terminal coiled-coil domain of p190RhoGEF. Binding was independent of a LD-like binding motif within p190RhoGEF, yet FAK association was disrupted by a mutation (Leu-1034 to Ser) that weakens the helical bundle structure of the FAK FAT domain. Neuro-2a cell binding to laminin increased endogenous FAK and p190RhoGEF tyrosine phosphorylation, and co-transfection of a dominant-negative inhibitor of FAK activity, termed FRNK, inhibited lamininstimulated p190RhoGEF tyrosine phosphorylation and p21 RhoA GTP binding. Overexpression of FAK in Neuro-2a cells increased both endogenous p190RhoGEF tyrosine phosphorylation and RhoA activity, whereas these events were inhibited by FRNK co-expression. Because insulin-like growth factor 1 treatment of Neuro-2a cells increased FAK tyrosine phosphorylation and enhanced p190RhoGEF-mediated activation of RhoA, our results support the conclusion that FAK association with p190RhoGEF functions as a signaling pathway downstream of integrins and growth factor receptors to stimulate Rho activity.     

肺炎链球菌溶血素的研究进展

肺炎链球菌溶血素(Pneumolysin,PLY)是肺炎链球菌的一种重要毒力因子,包含4个结构域,是胆固醇依赖性细胞溶血素(CDCs)的家族成员之一。PLY可广泛作用于宿主组织细胞,发挥细胞毒性作用。PLY可活化补体经典途径,诱导巨噬细胞和单核细胞等产生细胞因子,介导机体免疫应答过程。PLY是肺炎链球菌蛋白疫苗和相关小分子药物研制的重要靶标。本文就PLY的结构、功能及相关疫苗的最新研究进展进行综述。     

Sulfur dioxide derivatives modulate Na/Ca exchange currents and cytosolic [Ca2+]i in rat myocytes

We have recently shown that sulfur dioxide (SO(2)) derivatives (bisulfite and sulfite, 1:3 M/M) modulated L-type calcium, sodium, and potassium channels in rat myocytes. The aim of this study was to investigate whether SO(2) derivatives could alter Na/Ca exchanger current and the intracellular free [Ca(2+)]. The nickel-sensitive Na/Ca exchanger current was measured in rat myocytes exposed to ramp pulses in Tyrode's solution containing ouabain, nifedipine, and +/-Ni (5 mmol/l). Myocytes were loaded with the fluorescent Ca(2+) indicator Fura-2/AM to estimate intracellular Ca(2+) concentration. SO(2) derivatives significantly inhibited both outward and inward Ni-sensitive Na/Ca exchanger currents without a shift in the reversal potential. The intracellular free [Ca(2+)] was raised by SO(2) derivatives in several concentrations. SO(2) derivatives increased [Ca(2+)](i) in rat myocytes and its mechanism might involve SO(2) derivatives significantly inhibiting Na/Ca exchanger current and enhancing L-type calcium channel.     

Roles of alternative splicing in the functional properties of inner ear-specific KCNQ4 channels

The function of the KCNQ4 channel in the auditory setting is crucial to hearing, underpinned by the finding that mutations of the channel result in an autosomal dominant form of nonsyndromic progressive high frequency hearing loss. The precise function of KCNQ4 in the inner ear has not been established. However, recently we demonstrated that there is differential expression among four splice variants of KCNQ4 (KCNQ4_v1-v4) along the tonotopic axis of the cochlea. Alternative splicing specifies the outcome of functional channels by modifying the amino acid sequences within the C terminus at a site designated as the membrane proximal region. We show that variations within the C terminus of splice variants produce profound differences in the voltage-dependent phenotype and functional expression of the channel. KCNQ4_v4 lacks exons 9-11, resulting in deletion of 54 amino acid residues adjacent to the S6 domain compared with KCNQ4_v1. Consequently, the voltage-dependent activation of KCNQ4_v4 is shifted leftward by approximately 20 mV, and the number of functional channels is increased severalfold compared with KCNQ4_v1. The properties of KCNQ4_v2 and KCNQ4_v3 fall between KCNQ4_v1 and KCNQ4_v4. Because of variations in the calmodulin binding domains of the splice variants, the channels are differentially modulated by calmodulin. Co-expression of these splice variants yielded current magnitudes suggesting that the channels are composed of heterotetramers. Indeed, a dominant negative mutant of KCNQ4_v1 cripples the currents of the entire KCNQ4 channel family. Furthermore, the dominant negative KCNQ4 mutant stifles the activity of KCNQ2-5, raising the possibility of a global disruption of KCNQ channel activity and the ensuing auditory phenotype.     

Achieving stable myocardial regeneration after apical resection in neonatal mice

The neonatal heart completely regenerates after apical resection (AR), providing a desirable research model to study the mechanism of cardiac regeneration and cardiomyocyte proliferation. However, AR-induced neonatal heart regenerative phenomenon is controversial due to the variation of operative details in different laboratories. Here, we provide an optimized AR operation procedure with stable regeneration and high survival rate by achieving heart exposure, normalizing myocardium cut-offs, and reducing operation duration. We also established a whole-heart-slice approach to estimate the myocardial regeneration after the AR operation, which ensures no false-negative/positive results. The combination of the optimized AR operation and the whole-heart-slice analysis provides a stable system to study neonatal heart regeneration and cardiomyocyte proliferation in situ.