👤 Yee Siew Choong

Alginate oligosaccharides (AOS) have recently shown promising activities in inhibiting tumour growth in osteosarcomas. It is, however, unknown if AOS is also effective against nasopharyngeal carcinoma (NPC). To this end, the antiproliferation activities of enzymatically derived AOS were investigated against the EBV-positive NPC cell line, C666-1. MTT cytotoxicity assays revealed an antiproliferation effect against the C666-1 cell line, albeit at concentrations above 10 mg/mL, but promoting growth at lower concentrations. As a potential heparin sulfate analog, which also demonstrates a similar biphasic effect on cell proliferation, it was hypothesized that AOS may act on fibroblast growth factors (FGFs) and their receptors (FGFR) like heparin. This hypothesis was supported by in silico molecular docking, which discovered a similar binding pattern between AOS pentasaccharide and heparin pentasaccharide on FGF2, FGFR1 and FGF2-FGFR1 complex. Furthermore, all-atomic molecular dynamics simulations revealed that only the AOS pentasaccharide can pre-form the FGFR1 dimer for binding by FGF2 when one AOS molecule per FGFR1 dimer was simulated, while other AOS models (DP2-DP4) deformed the FGFR1 dimer to disfavour FGF2 binding during the simulations. In contrast, all AOS models (DP2-DP5) deformed the FGFR1 dimer when two AOS molecules per FGFR1 dimer were simulated without FGF2. These results suggest that the observed biphasic effects on cell proliferation by the AOS mixture may be attributed to the binding of the AOS pentasaccharide to the FGFR1/FGF2 proteins, although further experiments to validate this in silico observation are warranted. Show less

Lipoprotein lipase (LPL) is a blood vessel lipase that regulates and removes plasma lipoprotein triglycerides from blood circulation. It is important in the control of hypertriglyceridemia. LPL dysregulation can lead to hypertriglyceridemia and increase the risk of atherosclerosis cardiovascular disease. Therefore, the biochemical characterization of LPL could help understand the LPL dysregulation mechanism. However, active LPL enzyme acquisition via bacterial expression is challenging, as studies have reported that LPL could only be co-expressed in the presence of a chaperone. Therefore, this work intends to investigate the possibility of bacterial expression of human LPL (hLPL) with active lipase activity. The hLPL protein has been produced in SHuffle® T7 cells, and the optimal refolding conditions of the hLPL protein have been described here. The addition of 4% glycerol, 0.5-M NaCl, and 0.5-mM CaCl Show less

In adult skin wounds, collagen expression rapidly re-establishes the skin barrier, although the resultant scar is aesthetically and functionally inferior to unwounded tissue. Although TGFβ signaling and fibroblasts are known to be responsible for scar-associated collagen production, there are currently no prophylactic treatments for scar management. Fibroblasts in crosstalk with wound keratinocytes orchestrate collagen expression, although the precise paracrine pathways involved remain poorly understood. Herein, we showed that the matricellular protein, angiopoietin-like 4 (ANGPTL4), accelerated wound closure and reduced collagen expression in diabetic and ANGPTL4-knockout mice. Similar observations were made in wild-type rat wounds. Using human fibroblasts as a preclinical model for mechanistic studies, we systematically elucidated that ANGPTL4 binds to cadherin-11, releasing membrane-bound β-catenin which translocate to the nucleus and transcriptionally upregulate the expression of Inhibitor of DNA-binding/differentiation protein 3 (ID3). ID3 interacts with scleraxis, a basic helix-loop-helix transcription factor, to inhibit scar-associated collagen types 1α2 and 3α1 production by fibroblasts. We also showed ANGPTL4 interaction with cadherin-11 in human scar tissue. Our findings highlight a central role for matricellular proteins such as ANGPTL4 in the attenuation of collagen expression and may have a broader implication for other fibrotic pathologies. Show less