Development of bioabsorbable polylactide membrane with controllable hydrophilicity for adjustment of cell behaviours

Cell functions can be mediated through their interactions with the microenvironments, which highly depend on the surface state of the substrate. However, how to finely adjust the surface of biomaterials is still very challenging. In this study, poly(D,L-lactide) (PDLLA) with high molecular weight was synthesized via ring opening polymerization, which was hot-pressed into PDLLA membrane. In order to modify the hydrophobicity of the membrane (a limiting factor for its biomedical application), an amphiphilic monomethoxyl poly(ethylene glycol)-b-poly(D,L-lactide) (PEG-PDLLA) was selected to improve its surface hydrophilicity through a simple self-assembly approach. It was found that the contact angles of the modified membrane can be well controlled by variation of PEG-PDLLA concentrations. In vitro cell biological study indicates that optimized cell adhesion can be achieved on the modified membrane with a contact angle of around 50° via its self-assembly with an ethanol/water solution of PEG-PDLA (35 mg ml−1). The surface modification of the membrane also changed its biodegradation property in the process of its incubation period up to 240 days. The surface modification method may afford an effective way for adjustment of the surface (interface) of membrane (scaffolds) of different biomaterials, beyond polylactide.info:eu-repo/semantics/publishedVersio

A critical role for hepatic protein arginine methyltransferase 1 isoform 2 in glycemic control

Appropriate control of hepatic gluconeogenesis is essential for the organismal survival upon prolonged fasting and maintaining systemic homeostasis under metabolic stress. Here, we show protein arginine methyltransferase 1 (PRMT1), a key enzyme that catalyzes the protein arginine methylation process, particularly the isoform encoded by Prmt1 variant 2 (PRMT1V2), is critical in regulating gluconeogenesis in the liver. Liver‐specific deletion of Prmt1 reduced gluconeogenic capacity in cultured hepatocytes and in the liver. Prmt1v2 was expressed at a higher level compared to Prmt1v1 in hepatic tissue and cells. Gain‐of‐function of PRMT1V2 clearly activated the gluconeogenic program in hepatocytes via interactions with PGC1α, a key transcriptional coactivator regulating gluconeogenesis, enhancing its activity via arginine methylation, while no effects of PRMT1V1 were observed. Similar stimulatory effects of PRMT1V2 in controlling gluconeogenesis were observed in human HepG2 cells. PRMT1, specifically PRMT1V2, was stabilized in fasted liver and hepatocytes treated with glucagon, in a PGC1α‐dependent manner. PRMT1, particularly Prmt1v2, was significantly induced in the liver of streptozocin‐induced type 1 diabetes and high fat diet‐induced type 2 diabetes mouse models and liver‐specific Prmt1 deficiency drastically ameliorated diabetic hyperglycemia. These findings reveal that PRMT1 modulates gluconeogenesis and mediates glucose homeostasis under physiological and pathological conditions, suggesting that deeper understanding how PRMT1 contributes to the coordinated efforts in glycemic control may ultimately present novel therapeutic strategies that counteracts hyperglycemia in disease settings.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163465/10/fsb221018-sup-0005-FigS5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163465/9/fsb221018-sup-0001-FigS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163465/8/fsb221018-sup-0003-FigS3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163465/7/fsb221018-sup-0008-FigS8.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163465/6/fsb221018-sup-0002-FigS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163465/5/fsb221018_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163465/4/fsb221018.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163465/3/fsb221018-sup-0007-FigS7.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163465/2/fsb221018-sup-0006-FigS6.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163465/1/fsb221018-sup-0004-FigS4.pd

Identification of crucial modules and genes associated with backfat tissue development by WGCNA in Ningxiang pigs

Fat deposition is an economically important trait in pigs. Ningxiang pig, one of the four famous indigenous breeds in China, is characterized by high fat content. The underlying gene expression pattern in different developmental periods of backfat tissue remains unclear, and the purpose of this investigation is to explore the potential molecular regulators of backfat tissue development in Ningxiang pigs. Backfat tissue (three samples for each stage) was initially collected from different developmental stages (60, 120, 180, 240, 300, and 360 days after birth), and histological analysis and RNA sequencing (RNA-seq) were then conducted. Fragments per kilobase of transcript per million (FPKM) method was used to qualify gene expressions, and differentially expressed genes (DEGs) were identified. Furthermore, strongly co-expressed genes in modules, which were named by color, were clustered by Weighted gene co-expression network analysis (WGCNA) based on dynamic tree cutting algorithm. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment were subsequently implemented, and hub genes were described in each module. Finally, QPCR analysis was employed to validate RNA-seq data. The results showed that adipocyte area increased and adipocyte number decreased with development of backfat tissue. A total of 1,024 DEGs were identified in five comparison groups (120 days vs. 60 days, 180 days vs. 120 days, 240 days vs. 180 days, 300 days vs. 240 days, and 360 days vs. 300 days). The turquoise, red, pink, paleturquoise, darkorange, and darkgreen module had the highest correlation coefficient with 60, 120, 180, 240, 300, and 360 days developmental stage, while the tan, black and turquoise module had strong relationship with backfat thickness, adipocyte area, and adipocyte number, respectively. Thirteen hub genes (ACSL1, ACOX1, FN1, DCN, CHST13, COL1A1, COL1A2, COL6A3, COL5A1, COL14A1, OAZ3, DNM1, and SELP) were recognized. ACSL1 and ACOX1 might perform function in the early developmental stage of backfat tissue (60 days), and FN1, DCN, COL1A1, COL1A2, COL5A1, COL6A3, and COL14A1 have unignorable position in backfat tissue around 120 days developmental stage. Besides, hub genes SELP and DNM1 in modules significantly associated with backfat thickness and adipocyte area might be involved in the process of backfat tissue development. These findings contribute to understand the integrated mechanism underlying backfat tissue development and promote the progress of genetic improvement in Ningxiang pigs

Prolonged administration of total glucosides of paeony improves intestinal immune imbalance and epithelial barrier damage in collagen-induced arthritis rats based on metabolomics-network pharmacology integrated analysis

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovial inflammation and joint damage with complex pathological mechanisms. In recent years, many studies have shown that the dysregulation of intestinal mucosal immunity and the damage of the epithelial barrier are closely related to the occurrence of RA. Total glucosides of paeony (TGP) have been used clinically for the treatment of RA in China for decades, while the pharmacological mechanism is still uncertain. The purpose of this study was to investigate the regulatory effect and mechanism of TGP on intestinal immunity and epithelial barrier in RA model rats. The results showed that TGP alleviated immune hyperfunction by regulating the ratio of CD3+, CD4+ and CD8+ in different lymphocyte synthesis sites of the small intestine, including Peyer’s patches (PPs), intraepithelial lymphocytes (IELs), and lamina propria lymphocytes (LPLs). Specially, TGP first exhibited immunomodulatory effects on sites close to the intestinal lumen (IELs and LPLs), and then on PPs far away from the intestinal lumen as the administration time prolonged. Meanwhile, TGP restores the intestinal epithelial barrier by upregulating the ratio of villi height (V)/crypt depth (C) and expression of tight junction proteins (ZO-1, occludin). Finally, the integrated analysis of metabolomics-network pharmacology was also used to explore the possible regulation mechanism of TGP on the intestinal tract. Metabolomics analysis revealed that TGP reversed the intestinal metabolic profile disturbance in CIA rats, and identified 32 biomarkers and 163 corresponding targets; network pharmacology analysis identified 111 potential targets for TGP to treat RA. By intersecting the results of the two, three key targets such as ADA, PNP and TYR were determined. Pharmacological verification experiments showed that the levels of ADA and PNP in the small intestine of CIA rats were significantly increased, while TGP significantly decreased their ADA and PNP levels. In conclusion, purine metabolism may play an important role in the process of TGP improving RA-induced intestinal immune imbalance and impaired epithelial barrier

Numerical analysis of temperature field and thermal stress associated with dual-phase-lag heat conduction

A numerical method for generalized dual-phase-lag (DPL) heat conduction is proposed. Differential equations including the third-order derivative in time are obtained by using finite element space discretization and are solved by the finite difference method. The backward difference has less numerical oscillation but the central difference can better describe the sharp temperature change near the thermal wave front. In generality, the backward difference is an ideal method for the transient solution of the temperature field associated with the DPL model. However, the time step must be small enough so that the temperature field near the thermal wave front can be obtained accurately

A conductive line inclusion in thermoelectric materials : the thermoelectric fields and the effective thermoelectric properties

This paper studies a finite thermoelectric (TE) medium with an internal line inclusion which is electrically and thermal conductive. Exact solutions are obtained for the coupling and nonlinear thermoelectric fields. Based on the derived thermal and electrical fields, the effective thermoelectric properties (including thermal conductivity, electrical conductivity, Seebeck coefficient and figure-of-merit) of the inclusion/TE-medium system are expressed in explicit forms. It is found that there are upper bounds of the effective thermoelectric properties that the inclusion can enhance. Specifically, the effective thermal and electrically conductivities can be increased by 100%, the effective Seebeck coefficient and the figure-of-merit can be increased by 18% and 38%, respectively, by the inclusion. Since all the results are given in closed and explicit forms, they can be applied to the optimization of thermoelectric performance of thermoelectric materials in an effective and convenient way

Numerical modeling of elastic modulus and bucking load of honeycombs

In this paper, both equivalent Young's modulus and bucking load of the honeycombs are calculated using the finite element method. Honeycombs consisting of either regular hexagonal, equilateral triangular or square cells are considered. Numerical results are systematically compared with theoretical results from other literature. It is found that honeycombs display orthotropic properties. Such a fact is different from that reported in open literature. Moreover, the buckling modes are discussed, and the modified expressions of the equivalent modulus and bucking load are given

Strain gradient fracture of a mode III crack in an elastic layer on a substrate

This paper studies the problem of a mode III crack in an elastic layer on a substrate under the framework of strain gradient elasticity theory. The effects of volumetric and surface strain gradient parameters on the crack tip asymptotic stress and crack shape are investigated. Due to strain gradient effect, the crack opening, the magnitude of the stress ahead of the crack tip, and the stress intensity factor are significantly higher than those in classical linear elastic fracture mechanics. More significantly, the direction of the stress ahead of the crack tip with strain gradient is opposite to that in the classical linear elastic fracture mechanics. The conventional linear elastic fracture mechanics results are recovered when the gradient parameter reduces to zero. The influence of the substrate on the fracture mechanics parameters is very significant when the strain gradient effect of the materials is considered

Fracture mechanics analysis of an anti-plane crack in gradient elastic sandwich composite structures

The strain gradient elasticity theory is applied to the solution of a mode III crack in an elastic layer sandwiched by two elastic layers of infinite thickness. The model includes volumetric and surface strain gradient characteristic length parameters. Both the near-tip asymptotic stresses and the crack displacement are obtained. Due to stain gradient effects, the magnitudes of the stress ahead of the crack tip are significantly higher than those in the classical linear elastic fracture mechanics. When the gradient parameters reduce to sufficiently small, all results reduce to the conventional linear elastic fracture mechanics results. In addition to the single crack in the finite layer, the solution and the results for two collinear cracks are also established and given