Jyun-Yuan Huang

Collagen is an important material for biomedical research, but using mammalian tissue-derived collagen carries the risk of zoonotic disease transmission. Marine organisms, such as farmed tilapia, have emerged as a safe alternative source of collagen for biomedical research. However, the tilapia collagen products for biomedical research are rare, and their biological functions remain largely unexamined. In this study, we characterized a commercial tilapia skin collagen using SDS-PAGE and fibril formation assays and evaluated its effects on skin fibroblast adhesion, proliferation, and migration, comparing it with commercial collagen from rat tails, porcine skin, and bovine skin. The results showed that tilapia skin collagen is a type I collagen, similar to rat tail collagen, and has a faster fibril formation rate and better-promoting effects on cell migration than porcine and bovine skin collagen. We also confirmed its application in a 3D culture for kidney cells’ spherical cyst formation, fibroblast-induced gel contraction, and tumor spheroid interfacial invasion. Furthermore, we demonstrated that the freeze-dried tilapia skin collagen scaffold improved wound closure in a mouse excisional wound model, similar to commercial porcine or bovine collagen wound dressings. In conclusion, tilapia skin collagen is an ideal biomaterial for biomedical research.

Adipose-derived stem cells (ADSCs) have been implicated in tumor growth and metastasis in breast cancer. ADSCs exhibit tumor tropism, and are of increasing clinical relevance due to the autologous fat grafting for breast reconstruction. Although we have previously shown that a high level of the adipocytokine visfatin in human breast cancer tissues correlated with tumor progression mediated by cAbl and STAT3, the effects of visfatin in the tumor microenvironment are unclear. To understand how visfatin modulates breast cancer within the tumor-stromal environment, we examined determinants of breast cancer progression using a visfatin-primed ADSCs-tumor co-culture model. ADSCs were isolated from tumor-free adipose tissue adjacent to breast tumors. ADSCs were treated with or without visfatin for 48 h and then collected for co-culture with breast cancer cell line MDA-MB-231 for 72 h in a transwell system. We found that the MDA-MB-231 cells co-cultured with visfatin-treated ADSCs (vADSCs) had higher levels of cell viability, anchorage independent growth, migration, invasion, and tumorsphere formation than that co-cultured with untreated ADSCs (uADSCs). Growth differentiation factor 15 (GDF15) upregulation was found in the co-culture conditioned medium, with GDF15 neutralizing antibody blocking the promoting effect on MDA-MB-231 in co-culture. In addition, a GDF15-induced AKT pathway was found in MDA-MB-231 and treatment with PI3K/AKT inhibitor also reversed the promoting effect. In an orthotopic xenograft mouse model, MDA-MB-231 co-injected with vADSCs formed a larger tumor mass than with uADSCs. Positive correlations were noted between visfatin, GDF15, and phosphor-AKT expressions in human breast cancer specimens. In conclusion, visfatin activated GDF15-AKT pathway mediated via ADSCs to facilitate breast cancer progression.

Nucleotide-binding oligomerization domain (NACHT), leucine rich repeat (LRR) and pyrin domain (PYD) 7 containing protein, NLRP7, is a member of the NLR family which serves as innate immune sensors. Mutations and genetic variants of NLRP7 have been found in women with infertility associated conditions, such as recurrent hydatidiform mole, recurrent miscarriage, and preeclampsia. Decidualization of endometrial stromal cells is a hallmark of tissue remodeling to support embryo implantation and proper placental development. Given defective decidualization has been implicated in miscarriage as well as preeclampsia, we aimed to explore the link between the NLRP7 gene and decidualization. Endometrial samples obtained from pregnant women in the first trimester and non-pregnant women were used to study NLRP7 expression pattern. The human telomerase reverse transcriptase (hTERT)-immortalized human endometrial stromal cells (T-HESCs) were used to study the effect of NLRP7 on decidualization. Decidualization of T-HESCs was induced with 1 μM medroxyprogesterone acetate (MPA) and 0.5 mM 8-bromoadenosine 3':5'-cyclic monophosphate (8-Br-cAMP). siRNA was used to knock down NLRP7 while lentiviral vectors were used to overexpress NLRP7 in cells. NLRP7 expression was detected by immunofluorescence, qRT-PCR, and Western blotting. Decidualization markers, Insulin-like growth factor-binding protein 1 (IGFBP-1) and prolactin (PRL), were detected by qRT-PCR and ELISA. Nuclear translocation of NLRP7 was detected by the subcellular fractionation and confocal microscopy. The effect of NLRP7 on progesterone receptor (PR) activity was evaluated by a reporter system. NLRP7 was up-regulated in the decidual stromal cells of human first-trimester endometrium. After in vitro decidualization, T-HESCs presented with the swollen phenotype and increased expressions of IGFBP-1 and PRL. Knockdown or over-expression of NLRP7 reduced or enhanced the decidualization, respectively, according to the expression level of IGFBP-1. NLRP7 was found to translocate in the nucleus of decidualized T-HESCs and able to promote PR activity. NLRP7 was upregulated and translocated to the nucleus of the endometrial stromal cells in an in vitro decidualization model. Overexpressed NLRP7 promoted the IGFBP-1 expression and PR reporter activation. IGFBP-1 expression decreased with the knockdown of NLRP7. Therefore, we suggest that NLRP7 contributes to in vitro decidualization of endometrial stromal cells.

The development and differentiation of steroidogenic organs are controlled by Ad4BP/SF-1 (adrenal 4 binding protein/steroidogenic factor 1). Besides, lysosomal activity is required for steroidogenesis and also enables adrenocortical cell to survive during stress. However, the role of lysosomal activity on steroidogenic cell growth is as yet unknown. Here, we showed that lysosomal activity maintained Ad4BP/SF-1 protein stability for proper steroidogenic cell growth. Treatment of cells with lysosomal inhibitors reduced steroidogenic cell growth in vitro. Suppression of autophagy did not affect cell growth indicating that autophagy was dispensable for steroidogenic cell growth. When lysosomal activity was inhibited, the protein stability of Ad4BP/SF-1 was reduced leading to reduced S phase entry. Interestingly, treatment of cells with lysosomal inhibitors reduced glycolytic gene expression and supplying the cells with pyruvate alleviated the growth defect. ChIP-sequence/ChIP studies indicated that Ad4BP/SF-1 binds to the upstream region of Ccne1 (cyclin E1) gene during G1/S phase. In addition, treatment of zebrafish embryo with lysosomal inhibitor reduced the levels of the interrenal (adrenal) gland markers. Thus lysosomal activity maintains steroidogenic cell growth via stabilizing Ad4BP/SF-1 protein.

PROK1-V67I has been shown to play a role as a modifier gene in the PROK1-PROKR system of human early pregnancy. To explore the related modifier mechanism of PROK1-V67I, we carried out a comparison study at the gene expression level and the cell function alternation of V67I, and its wild-type (WT), in transiently-transfected cells. We, respectively, performed quantitative RT-PCR and ELISA assays to evaluate the protein and/or transcript level of V67I and WT in HTR-8/SV neo, JAR, Ishikawa, and HEK293 cells. Transiently V67I- or WT-transfected HTR-8/SV neo and HEK293 cells were used to investigate cell function alternations. The transcript and protein expressions were down-regulated in all cell lines, ranging from 20% to 70%, compared with WT. There were no significant differences in the ligand activities of V67I and WT with regard to cell proliferation, cell invasion, calcium influx, and tubal formation. Both PROK1 alleles promoted cell invasion and intracellular calcium mobilization, whereas they had no significant effects on cell proliferation and tubal formation. In conclusion, the biological effects of PROK1-V67I on cell functions are similar to those of WT, and the common variant of V67I may act as a modifier in the PROK1-PROKR system through down-regulation of PROK1 expression. This study may provide a general mechanism that the common variant of V67I, modifying the disease severity of PROK1-related pathophysiologies.

Do gene polymorphisms of two members of the human innate immune sensor nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing proteins (NLRP) family, NLRP2 and NLRP7, confer susceptibility to idiopathic recurrent miscarriage (RM)? We found a significant association of a tag single-nucleotide polymorphism (SNP) of NLRP7 (rs26949) with idiopathic RM, while a tag SNP of NLRP2 (rs127868) showed a marginally significant association. Human NLRP2 and NLRP7 have been suggested to be maternal effect genes, regulating early embryonic development and establishment of maternal imprints. Anecdotal evidence showed women who had experienced at least three consecutive miscarriages without hydatidiform mole carried non-synonymous NLRP7 variants. Whether these two genes are associated with idiopathic RM remains obscure. In this case-controlled study, 143 women who had experienced at least two consecutive spontaneous miscarriages (n = 91 women with two miscarriages, n = 52 with three or more) and 149 controls were included between 2004 and 2010. A total of five tag SNPs of NLRP2 and eight tag SNPs of NLRP7 were genotyped using the primer extension analysis. The deviation from the Hardy–Weinberg equilibrium was checked using χ² analysis. The logistic odds ratios (ORs) of RM were estimated with a 95% confidence interval (CI) in multivariate analysis after maternal age adjustment. The false discovery rate (FDR) was used to adjust for multiple testing. Tests for haplotype association with RM were performed. Gene–gene interactions among loci of the two genes were evaluated by using the multifactor dimensionality reduction (MDR) method. One tag SNP rs269949 of NLRP7 showed significant difference between patients and controls in a recessive model (FDR P = 0.0456, age-adjusted OR (AOR) = 16.49, 95% CI = 2.00–136.11 for the GG genotype). The difference was significant in patients with two consecutive miscarriages and also in those with three or more consecutive miscarriages. Meanwhile, one tag SNP of NLRP2 (rs12768) showed marginal significance between patients and controls in a co-dominant model (FDR P = 0.0505, AOR = 2.15, 95% CI = 1.29–3.58 for the AC genotype). In the haplotype analysis, NLRP2 and NLRP7 did not show any significant difference between the patients and controls. MDR test revealed that there is no significant gene–gene interaction among loci of NLRP2 and NLRP7. The results may be biased by heterogeneous ethnicities of the Taiwanese Han and a small sample size. The genetic loci responsible for the disease as well as their functional significance also await further investigation. Our study suggests the role of the NLRP family proteins in RM. This study was supported by grants from the National Science Council of the Republic of China (NSC-100-2314-B-006-011-MY3). None of the authors have any conflicts of interest.

Dense accumulations of T cells are often found in peritumoral areas, which reduce the efficiency of contact-dependent lysis of tumor cells. We demonstrate in this study that the extracellular matrix (ECM) produced by tumors can directly regulate T cell migration. The transmigration rate of several T cells including peripheral blood primary T cell, Jurkat, and Molt-4 measured for glioma cells or glioma ECM was consistently low. Jurkat cells showed reduced amoeba-like shape formation and delayed ERK activation when they were in contact with monolayers or ECM of glioma cells as compared with those in contact with HepG2 and MCF-7 cells. Phospho-ERK was located at the leading edge of migrating Jurkat cells. Glioma cells, but not MCF-7 and HepG2 cells, expressed tenascin-C. Knocking down the tenascin-C gene using the short hairpin RNA strategy converted glioma cells to a transmigration-permissive phenotype for Jurkat cells regarding ERK activation, transmigration, and amoeba-like shape formation. In addition, exogenous tenascin-C protein reduced the amoeba-like shape formation and transmigration of Jurkat cells through MCF-7 and HepG2 cell monolayers. A high level of tenascin-C was visualized immunohistochemically in glioma tumor tissues. CD3⁺ T cells were detected in the boundary tumor area and stained strongly positive for tenascin-C. In summary, glioma cells can actively paralyze T cell migration by the expression of tenascin-C, representing a novel immune suppressive mechanism achieved through tumor ECM.