A new model of myofibroblast-cardiomyocyte interactions and their differences across species

Although coupling between cardiomyocytes and myofibroblasts is well known to affect the physiology and pathophysiology of cardiac tissues across species, relating these observations to humans is challenging because the effect of this coupling varies across species and because the sources of these effects are not known. To identify the sources of cross-species variation, we built upon previous mathematical models of myofibroblast electrophysiology and developed a mechanoelectrical model of cardiomyocyte-myofibroblast interactions as mediated by electrotonic coupling and transforming growth factor-β1. The model, as verified by experimental data from the literature, predicted that both electrotonic coupling and transforming growth factor-β1 interaction between myocytes and myofibroblast prolonged action potential in rat myocytes but shortened action potential in human myocytes. This variance could be explained by differences in the transient outward K⁺ current associated with differential Kv4.2 gene expression across species. Results are useful for efforts to extrapolate the results of animal models to the predicted effects in humans and point to potential therapeutic targets for fibrotic cardiomyopathy.     

Molecular guidance cues in the development of visual pathway

70%–80% of our sensory input comes from vision. Light hit the retina at the back of our eyes and the visual information is relayed into the dorsal lateral geniculate nuclei (dLGN) and primary visual cortex (V1) thereafter, constituting the image-forming visual circuit. Molecular cues are one of the key factors to guide the wiring and refinement of the image-forming visual circuit during pre- and post-embryonic stages. Distinct molecular cues are involved in different developmental stages and nucleus, suggesting diverse guidance mechanisms. In this review, we summarize molecular guidance cues throughout the image-forming visual circuit, including chiasm determination, eye-specific segregation and refinement in the dLGN, and at last the reciprocal connections between the dLGN and V1.     

Level of habitat fragmentation determines its non-linear relationships with plant speciesn richness,frequency and density at desertified grasslands in Inner Mongolia,China

Aims This study aimed to examine the changes in plant species richness, frequency and density along a habitat fragmentation gradient (with varied degrees of habitat fragmentation [DHFs]) in a desertified grassland of Horqin Sandy Land, northeastern Inner Mongolia, China.     

Umbilical cord-derived mesenchymal stem cell transplantation for treating elderly vascular dementia

This study aimed to determine the efficacy and safety of human umbilical cord-derived mesenchymal stem cell (HUC-MSC) transplantation for treating elderly vascular dementia (VaD). Ten VaD patients (average age, 73.88 years old) were treated. HUC-MSCs were isolated, cultured, stem cell-marked, and qualified and administered as a 3-course intravenous infusion to these patients. The Mini-Mental State Exam (MMSE) and the Activities of Daily Living Index (Barthel Index scoring system) were used to assess the cognitive function and daily living activity improvements in these patients before transplantation (T0), 3 months after transplantation (T1), and 6 months after transplantation (T2). The MMSE and Barthel Index scores were 15.80 ± 5.49 and 42.00 ± 9.33 points at T0, respectively, and were significantly different when compared with those at T1 (19.20 ± 6.39 and 49.20 ± 10.86 points, respectively, P < 0.05), whereas there was no difference when compared with those at T2 (14.00 ± 6.55 and 40.70 ± 10.37 points, respectively, P > 0.05). HUC-MSC transplantation was safe and feasible for VaD and improved early cognitive functions and daily living activities in VaD patients to a certain extent, thus improving patients’ quality of life.     

ADP‐glucose pyrophosphorylase genes,associated with kernel weight,underwent selection during wheat domestication and breeding

ADP‐glucose pyrophosphorylase, comprising two small subunits and two large subunits, is considered a key enzyme in the endosperm starch synthesis pathway in wheat (Triticum aestivum L.). Two genes, TaAGP‐S1‐7A and TaAGP‐L‐1B, were investigated in this study. Haplotypes of these genes were associated with thousand kernel weight (TKW) in different populations. Mean TKWs of favoured haplotypes were significantly higher than those of nonfavoured ones. Two molecular markers developed to distinguish these haplotypes could be used in molecular breeding. Frequencies of favoured haplotypes were dramatically increased in cultivars released in China after the 1940s. These favoured haplotypes were also positively selected in six major wheat production regions globally. Selection of AGP‐S1 and AGP‐L‐1B in wheat mainly occurred during and after hexaploidization. Strong additive effects of the favoured haplotypes of with other genes for starch synthesis were also detected in different populations.     

Dual-drug loaded nanoneedles with targeting property for efficient cancer therapy

Background

Since the anticancer drugs have diverse inhibited mechanisms to the cancer cells, the use of two or more kinds of anticancer agents may achieve excellent therapeutic effects, especially to the drug-resistant tumors.

Results

In this study, we developed a kind of dual drug [methotrexate (MTX) and 10-hydroxycamptothecine (HCPT)] loaded nanoneedles (DDNDs) with pronounced targeting property, high drug loading and prolonged drug release. The anti-solvent precipitation of the HCPT and MTX modified PEG-b-PLGA (PEG-b-PLGA-MTX, PPMTX) leads to nucleation of nanoneedles with nanocrystalline HCPT as the core wrapped with PPMTX as steric stabilizers. In vitro cell uptake studies showed that the DDNDs revealed an obviously targeting property and entered the HeLa cells easier than the nanoneedles without MTX modification. The cytotoxicity tests illustrated that the DDNDs possessed better killing ability to HeLa cells than the individual drugs or their mixture in the same dose, indicating its good synergistic effect and targeting property. The in vivo studies further confirmed these conclusions.

Conclusions

This approach led to a promising sustained drug delivery system for cancer diagnosis and treatment.

     

Research Progress on Karst Tiankeng Ecosystems

The geomorphologic features called tiankengs were first discovered and named at the end of the twentieth century in karst areas of China. They have enjoyed increasing attention owing to their unusual geologic processes and unique ecological communities. However, the understanding of classification, geomorphic evolution, developmental conditions, geological dating and ecological environments of tiankengs are still extensively disputed by geomorphologists and geologists. This article focuses on combining all main areas of recent research activities from three aspects: development, evolution and transformation of karst tiankengs; biodiversity of karst tiankeng forests; and the impact of human activities on karst tiankeng ecosystems. Finally, we suggest future direction for research on karst tiankeng ecosystems: (1) multidisciplinary systematic study; (2) processes of ecological change and environmental effects under the influence of both natural and human impacts; (3) research on their protection, rational utilization, and sustainable management.     

Cx43 deficiency confers EMT-mediated tamoxifen resistance to breast cancer via c-Src/PI3K/Akt pathway

Tamoxifen (TAM) resistance has indicated a significant challenge during endocrine therapy for hormone-sensitive breast cancer. Thus, it is significant to elucidate the molecular events endowing TAM resistance to endocrine therapy. In this study, we found that epithelial-mesenchymal transition (EMT) was an important event to confer TAM resistance, and attenuating EMT by elevating connexin (Cx) 43 expression could reverse TAM resistance. Specifically, Cx43 overexpression improved TAM sensitivity, while Cx43 depletion facilitated TAM insensitivity by modulating EMT in T47D TAM-resistant and -sensitive cells, and transplanted xenografts. Importantly, we found a novel reciprocal regulation between Cx43 and c-Src/PI3K/Akt pathway contributing to EMT and TAM resistance in breast cancer. Moreover, we identified that Cx43 deficiency was significantly correlated with poor relapse-free survival in patients undergoing TAM treatment. Therefore, Cx43 represents a prognostic marker and an attractive target for breast cancer treatments. Therapeutic strategies designed to increase or maintain Cx43 function may be beneficial to overcome TAM resistance.