ABSTRACT. Tissue development is orchestrated by the coordinated activities of both chemical and physical regulators. While much attention has been given to the role that chemical regulators play in driving development, researchers have recently begun to elucidate the important role that the mechanical properties of the extracellular environment play. For instance, the stiffness of the extracellular environment has a role in orienting cell division, maintaining tissue boundaries, directing cell migration, and driving differentiation. In addition, extracellular matrix stiffness is important for maintaining normal tissue homeostasis, and when matrix mechanics become imbalanced, disease progression may ensue. In this article, we will review the important role that matrix stiffness plays in dictating cell behavior during development, tissue homeostasis, and disease progression.
Targeted protein degradation (TPD) technology has drawn significant attention from researchers in both academia and industry. It is rapidly evolved as a new therapeutic modality and also a useful chemical tool in selectively depleting various protein targets. As most efforts focus on cytosolic proteins using PROteolysis TArgeting Chimera (PROTAC), LYsosome TArgeting Chimera (LYTAC) recently emerged as a promising technology to deliver extracellular protein targets to lysosome for degradation through the cation-independent mannose-6-phosphate receptor (CI-M6PR). In this study, we exploited the potential of the asialoglycoprotein receptor (ASGPR), a lysosomal targeting receptor specifically expressed on liver cells, for the degradation of extracellular proteins including membrane proteins. The ligand of ASGPR, triantennary N -acetylgalactosamine (tri-GalNAc), was conjugated to biotin, antibodies, or fragments of antibodies to generate a new class of degraders. We demonstrated that the extracellular protein targets could be successfully internalized and delivered into lysosome for degradation in liver cell lines specifically by these degraders. This work will add a new dimension to TPD with cell type specificity.
We present a simple descriptive study of maternal health care utilization among ethnic minority women in a remote region of China. Factors that affect women obtaining care and their decision-making are explored. Results show that utilization of maternal health care services is associated with a range of social, economic, cultural and geographic factors as well as the policies of the state and the delivery of services. Utilization is not necessarily increased through easy access to a health facility. We identify potential for improving utilization through developing the role of village-based health care workers, expanding mobile antenatal care clinics and changing the way township hospital services are provided and funded. This would include modifications to rural health insurance schemes. Several of these changes are achievable at the township or county level. The findings of this study provide insights that can be used by local health providers, planners and decision-makers to improve the provision of maternal health care services to ethnic minority women.
This paper reports the results of exploratory research on reproductive and sexual health knowledge and sexual behaviour of young, unmarried women who migrate to cities from rural areas for work, and their access to and needs in relation to family planning in Beijing, Guangzhou, Shanghai, Guiyang and Taiyuan, in China. Focus group discussions were conducted with 146 young women aged 16-25 and 58 in-depth interviews with key informants. Some of the young female migrant workers were sexually active and living with their boyfriends, most of whom expected to marry each other. Most of the women lacked basic information about reproduction and contraception, and did not know where or how to obtain contraception. There were social, psychological and economic barriers to accessing services. Only a small proportion of those who were unmarried were using contraception, so induced abortion was often the outcome of unprotected premarital sex. Pleasing male partners also played an important role in unprotected sex. The training, attitudes and approach of the entire family planning service system in relation to unmarried and young people in China, including this migrant population, needs to be reorientated so as to provide them with appropriate and adequate services.
Mesenchymal stem cells (MSCs) have been extensively used for cell therapies and tissue engineering. The current MSC strategy requires a large quantity of cells for such applications, which can be achieved through cell expansion in culture. In the body, stem cell fate is largely determined by their microenvironment, known as the niche. The complex and dynamic stem cell niche provides physical, mechanical, and chemical cues to collaboratively regulate cell activities. It remains a great challenge to maintain the properties of MSCs in culture. Constructing a microenvironment as an engineered stem cell niche in culture to maintain MSC phenotypes, properties, and functions is a viable strategy to address the issue. Here, we review the current understanding of MSC behavior in the bone marrow niche, describe different strategies to engineer an in vitro microenvironment for maintaining MSC properties and functions, and discuss previous findings on environmental factors critical to the modulation of MSC activities in engineered microenvironments.
Each year malaria kills hundreds of thousands of people and infects hundreds of millions of people despite current control measures. An effective malaria vaccine will likely be necessary to aid in malaria eradication. Vaccination using whole sporozoites provides an increased repertoire of immunogens compared to subunit vaccines across at least two life cycle stages of the parasite, the extracellular sporozoite, and intracellular liver stage. Three potential whole sporozoite vaccine approaches are under development and include genetically attenuated parasites, radiation attenuated sporozoites, and wild-type sporozoites administered in combination with chemoprophylaxis. Pre-clinical and clinical studies have demonstrated whole sporozoite vaccine immunogenicity, including humoral and cellular immunity and a range of vaccine efficacy that depends on the pre-exposure of vaccinated individuals. While whole sporozoite vaccines can provide protection against malaria in some cases, more recent studies in malaria-endemic regions demonstrate the need for improvements. Moreover, challenges remain in manufacturing large quantities of sporozoites for vaccine commercialization. A promising solution to the whole sporozoite manufacturing challenge is in vitro culturing methodology, which has been described for several Plasmodium species, including the major disease-causing human malaria parasite, Plasmodium falciparum. Here, we review whole sporozoite vaccine immunogenicity and in vitro culturing platforms for sporozoite production.
Stiffness of biomaterial substrates plays a critical role in regulation of cell behavior. Although the effect of substrate stiffness on cell behavior has been extensively studied, molecular mechanisms of regulation rather than those involving cytoskeletal activities still remain elusive. In this study, we fabricated aligned ultrafine fibers and treated the fiber with different annealing temperatures to produce fibrous substrates with different stiffness. Human mesenchymal stem cells (hMSCs) were then cultured on these fibrous substrates. Our results showed that annealing treatment did not change the diameter of electrospun fibers but increased their polymer crystallinity and mechanical properties. The mRNA expression of RUNX2 was upregulated while the mRNA expression of scleraxis was downregulated in response to an increase in substrate stiffness, suggesting that increased stiffness favorably drives hMSCs into the osteogenic lineage. With subsequent induction of osteogenic differentiation, osteogenesis of hMSCs on stiffer substrates was increased compared to that of the cells on control substrates. Cells on stiffer substrates increasingly activated AKT and YAP and upregulated transcript expression of YAP target genes compared to those on control substrates, and inhibition of AKT led to decreased expression of YAP and RUNX2. Furthermore, macrophage migration inhibitory factor (MIF) was increasingly produced by the cell on stiffer substrates, and knocking down MIF by siRNA resulted in decreased AKT phosphorylation. Taken together, we hereby demonstrate that simply using the annealing approach can manipulate stiffness of an aligned fibrous substrate without altering the material chemistry, and substrate stiffness dictates hMSC differentiation through the MIF-mediated AKT/YAP/RUNX2 pathway.
This paper comments on the provision of birthing services in Sichuan and Shanxi Provinces in China within a policy context. The goal was to understand possible unintended and harmful health outcomes for women in the light of international evidence, to better inform practice and policy development. Data were collected from October 2005 to April 2007 in 25 hospitals across 13 counties and one city. Normal and caesarean birth records were audited, observations made of facilities and interviews conducted with officials, administrators, health workers, women who delivered in hospital facilities and women who delivered at home. We argue that in the context of a neo-liberal health economy with poorly developed government regulatory policies, those with the power to pay for maternity care may be vulnerable to a new range of risks to their health from those positioned to make a profit. While poor communities may lack access to basic services, wealthier socio-economic groups may risk an increase in maternal morbidity and mortality through the overuse of avoidable intervention. We recommend a stronger evidence base for hospital maternity services and changes to the role of the State in countering systemic problems.
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