It is well established that extracellular matrix (ECM) stiffness plays a significant role in regulating the phenotypes and behaviors of many cell types. However, the mechanism underlying the sensing of mechanical cues and subsequent elasticity-triggered pathways remains largely unknown. We observed that stiff ECM significantly enhanced the expression level of several members of the Wnt/β-catenin pathway in both bone marrow mesenchymal stem cells and primary chondrocytes. The activation of β-catenin by stiff ECM is not dependent on Wnt signals but is elevated by the activation of integrin/ focal adhesion kinase (FAK) pathway. The accumulated β-catenin then bound to the wnt1 promoter region to up-regulate the gene transcription, thus constituting a positive feedback of the Wnt/β-catenin pathway. With the amplifying effect of positive feedback, this integrin-activated β-catenin/Wnt pathway plays significant roles in mediating the enhancement of Wnt signal on stiff ECM and contributes to the regulation of mesenchymal stem cell differentiation and primary chondrocyte phenotype maintenance. The present integrin-regulated Wnt1 expression and signaling contributes to the understanding of the molecular mechanisms underlying the regulation of cell behaviors by ECM elasticity.
Abstract. Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and inaccessible regions in the world,
Abstract. The Tibetan Plateau (TP) plays a critical role in influencing regional and global climate, via
both thermal and dynamical mechanisms. Meanwhile, as the largest high-elevation part of the
cryosphere outside the polar regions, with vast areas of mountain glaciers, permafrost and
seasonally frozen ground, the TP is characterized as an area sensitive to global climate
change. However, meteorological stations are biased and sparsely distributed over the TP, owing to
the harsh environmental conditions, high elevations, complex topography and heterogeneous
surfaces. Moreover, due to the weak representation of the stations, atmospheric conditions and the
local land–atmosphere coupled system over the TP as well as its effects on surrounding regions are
poorly quantified. This paper presents a long-term (2005–2016) in situ observational dataset of
hourly land–atmosphere interaction observations from an integrated high-elevation and cold-region
observation network, composed of six field stations on the TP. These in situ observations contain
both meteorological and micrometeorological measurements including gradient meteorology, surface
radiation, eddy covariance (EC), soil temperature and soil water content profiles. Meteorological
data were monitored by automatic weather stations (AWSs) or planetary boundary layer (PBL)
observation systems. Multilayer soil temperature and moisture were recorded to capture vertical
hydrothermal variations and the soil freeze–thaw process. In addition, an EC system consisting of
an ultrasonic anemometer and an infrared gas analyzer was installed at each station to capture the
high-frequency vertical exchanges of energy, momentum, water vapor and carbon dioxide within the
atmospheric boundary layer. The release of these continuous and long-term datasets with hourly
resolution represents a leap forward in scientific data sharing across the TP, and it has been
partially used in the past to assist in understanding key land surface processes. This dataset is
described here comprehensively for facilitating a broader multidisciplinary community by enabling
the evaluation and development of existing or new remote sensing algorithms as well as geophysical
models for climate research and forecasting. The whole datasets are freely available at the Science
Data Bank (https://doi.org/10.11922/sciencedb.00103; Ma et al., 2020) and additionally at
the National Tibetan Plateau Data Center
(https://doi.org/10.11888/Meteoro.tpdc.270910, Ma 2020).
Background: In planning a randomized controlled trial of acupuncture, we conducted a pilot study using validated outcome measures to assess the feasibility of the protocol, and to obtain preliminary data on efficacy and tolerability of 3 different forms of acupuncture treatment as an adjunct for the treatment of chronic pain in patients with Rheumatoid arthritis (RA).
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