Search Results (3)

Candida albicans is an opportunistic pathogenic yeast that can survive in both normoxic and hypoxic environments. The involvement of C. albicans secretome on host biological processes has been demonstrated. However, the immunoregulatory function of C. albicans secretome released under hypoxic condition remains unclear. This study demonstrated the differences in cytokine responses and protein profiles between secretomes prepared under normoxic and hypoxic conditions. Furthermore, the immunoregulatory effects of heat shock protein SSA1(Ssa1), a protein candidate enriched in the hypoxic secretome, were investigated. Stimulation of mouse bone marrow-derived macrophages (BMMs) with Ssa1 resulted in the significant production of interleukin (IL)-10, IL-6, and tumor necrosis factor (TNF)-α as well as the significant expression of M2b macrophage markers (CD86, CD274 and tumor necrosis factor superfamily member 14), suggesting that C. albicans Ssa1 may promote macrophage polarization towards an M2b-like phenotype. Proteomic analysis of Ssa1-treated BMMs also revealed that Ssa1 reduced inflammation-related factors (IL-18-binding protein, IL-1 receptor antagonist protein, OX-2 membrane glycoprotein and cis-aconitate decarboxylase) and enhanced the proteins involved in anti-inflammatory response (CMRF35-like molecule 3 and macrophage colony-stimulating factor 1 receptor). Based on these results, we investigated the effect of Ssa1 on C. albicans infection and showed that Ssa1 inhibited the uptake of C. albicans by BMMs. Taken together, our results suggest that C. albicans alters its secretome, particularly by promoting the release of Ssa1, to modulate host immune response and survive under hypoxic conditions. Full article

Engineering the yeast Yarrowia lipolytica as an efficient host to produce recombinant proteins remains a longstanding goal for applied biocatalysis. During the protein overproduction, the accumulation of unfolded and misfolded proteins causes ER stress and cell dysfunction in Y. lipolytica. In this study, we evaluated the effects of several potential ER chaperones and translocation components on relieving ER stress by debottlenecking the protein synthetic machinery during the production of the endogenous lipase 2 and the E. coli β-galactosidase. Our results showed that improving the activities of the non-dominant translocation pathway (SRP-independent) boosted the production of the two proteins. While the impact of ER chaperones is protein dependent, the nucleotide exchange factor Sls1p for protein folding catalyst Kar2p is recognized as a common contributor enhancing the secretion of the two enzymes. With the identified protein translocation components and ER chaperones, we then exemplified how these components can act synergistically with Hac1p to enhance recombinant protein production and relieve the ER stress on cell growth. Specifically, the yeast overexpressing Sls1p and cytosolic heat shock protein Ssa8p and Ssb1p yielded a two-fold increase in Lip2p secretion compared with the control, while co-overexpressing Ssa6p, Ssb1p, Sls1p and Hac1p resulted in a 90% increase in extracellular β-galp activity. More importantly, the cells sustained a maximum specific growth rate (μ_max) of 0.38 h⁻¹ and a biomass yield of 0.95 g-DCW/g-glucose, only slightly lower than that was obtained by the wild type strain. This work demonstrated engineering ER chaperones and translocation as useful strategies to facilitate the development of Y. lipolytica as an efficient protein-manufacturing platform. Full article

Despite the importance of the early detection of glaucoma, most patients with progressive glaucoma show minimal symptoms. We aimed to evaluate biomarkers for glaucoma diagnosis in Korea. Forty-two volunteers with/without open-angle glaucoma were enrolled from January through October 2015—divided into a control or open-angle glaucoma group, which was further divided into normal-tension glaucoma (NTG) and high-tension glaucoma (HTG) groups—and underwent assessments for myelin basic protein (MBP), heat shock protein 60, anti-Sjögren’s-syndrome-related antigen A (SSA) and antigen B (SSB), anti-α-fodrin, and anti-nucleic acid. The glaucoma group showed a higher serum MBP level and lower serum anti-α-fodrin antibody level than the control group (p < 0.05). The NTG group showed higher serum anti-SSA and anti-SSB levels and lower anti-α-fodrin IgG/IgA levels than the HTG group. In the receiver operating characteristic curve analysis, the area under the curve (AUC) for serum MBP level was 0.917 in discriminating between controls and patients with glaucoma. Between the NTG and HTG groups, anti-SSA, anti-SSB, and anti-α-fodrin IgG/IgA levels showed an AUC above 0.8. Thus, these biomarkers were useful for diagnosing glaucoma and discriminating between controls and patients with glaucoma, and patients with NTG and HTG. Full article