Antrodia salmonea-induced oxidative stress abrogates HER-2 signaling cascade and enhanced apoptosis in ovarian carcinoma cells.

Antrodia salmonea is well known in Taiwan as a traditional Chinese medicinal fungus and has demonstrated antioxidant, anti-inflammatory, and anticancer effects. However, the anticancer activity of A. salmonea against human ovarian cancer is still elusive. Therefore, we investigated the antiovarian tumor activity of a fermented culture broth of A. salmonea and exhibits its underlying molecular mechanism. A. salmonea shows a significant effect on cell viability in human ovarian carcinoma (SKOV-3 or A2780) cell lines with an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Increased terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells and annexin V-propidium iodide stained cells indicate that A. salmonea induces late apoptosis in SKOV-3 cells. Notably, treatment with A. salmonea induced the following events: Apoptosis; caspase-3, -8, -9 and poly(ADP-ribose) polymerase activation; first apoptosis signal (Fas) and Fas ligand activation; Bid cleavage; and Bax2-B-cell lymphoma 2 dysregulation. The results show that A. salmonea-induced apoptosis was mediated by both mitochondrial and death receptor pathways. An increase in intracellular reactive oxygen species (ROS) was also observed in A. salmonea-treated cells, whereas the antioxidant N-acetylcysteine (NAC) prevented A. salmonea-induced cell death and DNA fragmentation, indicating that A. salmonea-induced apoptosis was mediated by ROS generation. Interestingly, A. salmonea-induced apoptosis is associated with the suppression of human epidermal growth factor receptor-2 (HER-2/neu) and phosphoinositide 3-kinase (PI3K)-protein kinase B (AKT) expression in HER-2/neu overexpressing SKOV-3 cells. NAC significantly prevented A. salmonea-induced HER-2/neu depletion and PI3K/AKT inactivation, indicating that A. salmonea-triggered apoptosis is mediated by ROS-inhibited HER-2/neu signaling cascades. To our knowledge, this is the first report describing the anticancer activity of this potentially beneficial mushroom against human ovarian carcinoma.

Trans-acting oligodeoxythymidine phosphorothioate triester reagents for transient transfection optimized and facilitated by a high-throughput microbioreactor system.

A rapid and cost-effective transient transfection method for mammalian cells is essential for screening biopharmaceuticals in early stages of development. A library of 25 amphipathic trans-acting oligodeoxythymidine phosphorothioate triester (dTtaPS) transfection reagents, carrying positively charged and lipophilic groups, has been constructed for this purpose. High-throughput screening of the library, using an imaging cytometer and an automated microbioreactor system, has led to the identification of dTtaPS10+ as a potent transfection reagent. This reagent efficiently delivers a plasmid encoding enhanced green fluorescent protein in adherent HeLa cells while exhibiting low cytotoxicity. The microbioreactor system has been particularly useful for assessing the ability of dTtaPS10+ to deliver a plasmid encoding immunoglobulin IgG1 in a fed-batch serum-free suspension CHO cell culture; dTtaPS10+ -mediated transfection resulted in the production of IgG1 in yields comparable to or better than those obtained with commercial lipid-based transfection reagents under similar conditions. The ability of dTtaPS10+ to deliver plasmids is essentially unaffected by the presence of a silicone-based antifoaming reagent, which is commonly used in bioreactor cell cultures. The transfection efficiency of lyophilized dTtaPS10+ -plasmid complexes has been significantly restored upon aqueous reconstitution when compared to that achieved while using commercial transfection reagent complexes under similar conditions. The results of all experiments underscore the potential of dTtaPS10+ for transient transfection of plasmids into adherent cells and fed-batch serum-free suspension CHO cells and rapid screening of reagents in a microbioreactor system.

Impact of media and antifoam selection on monoclonal antibody production and quality using a high throughput micro-bioreactor system.

Monoclonal antibody production in commercial scale cell culture bioprocessing requires a thorough understanding of the engineering process and components used throughout manufacturing. It is important to identify high impact components early on during the lifecycle of a biotechnology-derived product. While cell culture media selection is of obvious importance to the health and productivity of mammalian bioreactor operations, other components such as antifoam selection can also play an important role in bioreactor cell culture. Silicone polymer-based antifoams were known to have negative impacts on cell health, production, and downstream filtration and purification operations. High throughput screening in micro-scale bioreactors provides an efficient strategy to identify initial operating parameters. Here, we utilized a micro-scale parallel bioreactor system to study an IgG1 producing CHO cell line, to screen Dynamis, ProCHO5, PowerCHO2, EX-Cell Advanced, and OptiCHO media, and 204, C, EX-Cell, SE-15, and Y-30 antifoams and their impacts on IgG1 production, cell growth, aggregation, and process control. This study found ProCHO5, EX-Cell Advanced, and PowerCHO2 media supported strong cellular growth profiles, with an IVCD of 25-35 × 106 cells-d/mL, while maintaining specific antibody production (Qp > 2 pg/cell-d) for our model cell line and a monomer percentage above 94%. Antifoams C, EX-Cell, and SE-15 were capable of providing adequate control of foaming while antifoam 204 and Y-30 noticeably stunted cellular growth. This work highlights the utility of high throughput micro bioreactors and the importance of identifying both positive and negative impacts of media and antifoam selection on a model IgG1 producing CHO cell line. © 2017 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 34:262-270, 2018.

Efficacy and safety of secukinumab in Taiwanese patients with moderate to severe plaque psoriasis: Subanalysis from ERASURE phase III study.

The efficacy and safety of secukinumab, a fully human anti-interleukin-17A monoclonal antibody, has been evaluated for moderate to severe plaque psoriasis in global trials which have included a low proportion of Asian subjects. We analyzed the efficacy and safety of secukinumab in Taiwanese patients in a phase III global clinical trial (ERASURE). Fifty-one Taiwanese patients were randomized into s.c. placebo, 150 and 300 mg secukinumab treatment groups. The proportions of patients who achieved 75% or more improvement in Psoriasis Area and Severity Index (PASI-75) at week 12 were 87.5% with 300 mg secukinumab, 70% with 150 mg secukinumab, 0% with placebo. Of the patients receiving 300 mg secukinumab, 68.8% achieved PASI-90 at week 12. Analysis of overall patients receiving 300 mg secukinumab for 12 weeks showed that the proportion of PASI-75 responders was less in patients with body mass index of 25 or more than less than 25. During the entire 52 weeks, the incidence of adverse events (AE) was consistent with the overall population in ERASURE. The most common AE (cases/per 100 patient-year) during the entire treatment period were upper respiratory tract infection and pruritus. The duration of upper respiratory tract infection per 100 patient-year was approximately 399 days in placebo, 1261 days in 150 mg secukinumab and 1805 days in 300 mg secukinumab. The safety and efficacy of secukinumab in Taiwanese patients was compatible with the global phase III study in the treatment of moderate to severe plaque psoriasis.

Toona sinensis Inhibits Murine Leukemia WEHI-3 Cells and Promotes Immune Response In Vivo.

Toona sinensis (TS) is one of the most popular vegetarian dishes in Taiwan. It has been shown to exhibit antioxidant, antiangiogenic, antiatherosclerotic, and anticancer properties. In this study, we demonstrated the ability of aqueous leaf extracts from TS to promote immune responses in BALB/c mice and to exhibit anti-leukemia activity in murine WEHI-3 cells. BALB/c mice were injected intravenously with WEHI-3 cells and then treated orally with TS (50 mg/kg). In vivo study showed that TS treatment reduced liver and spleen enlargement in WEHI-3 bearing mice compared with the untreated group. Furthermore, TS also decreased white blood cells (WBC), indicating inhibition of differentiation of the precursor of macrophages in WEHI-3 bearing mice. Treatment of WEHI-3 cells with TS (0-75 µg/mL for 24 hours) significantly reduced cell viability. Furthermore, TS treatment-induced late apoptosis was confirmed by Annexin-V/PI staining. Western blot analyses revealed that treatment of WEHI-3 cells with TS statistically increased the protein expression level of cytochrome c in the cytoplasm and activates caspase-3. Notably, TS treatment caused a dramatic reduction in Bcl-2 and increase in Bax protein levels. TS may disturb the Bcl-2 and Bax protein ratio and induce apoptosis. This reports confirms the antitumor activity of this nutritious vegetable potentially against leukemia.

A Case Report of Majocchi's Granuloma Associated with Combined Therapy of Topical Steroids and Adalimumab.

Currently, tumor necrosis factor alpha (TNF-alpha) inhibitors are widely used for many autoimmune disorders. However, they cause an immunocompromised status that sometimes leads to many cutaneous side effects including atypical infections. Herein, we report the first case of adalimumab-related Majocchi's granuloma.A 43-year-old Taiwanese male patient with chronic plaque-type psoriasis developed numerous tender nodules 1 month after adalimumab injection. The nodules responded poorly to bacterial folliculitis treatment. After repeated skin biopsies for pathology and tissue fungal culture, Majocchi's granuloma was confirmed. Adalimumab was withheld, and 12 weeks of terbinafine treatment was given. On completion of treatment, the nodular skin lesions and dystrophic nail lesions improved dramatically.The information, including time span, clinical features, histological findings, and improvement following withdrawal of adalimumab and treatment with an oral antifungal agent, indicates that Majocchi's granuloma was adalimumab-related. Psoriasis patients are more susceptible to dermatophyte infection due to local and systemic immunosuppressant therapy. It is important to perform a thorough examination for latent dermatophyte infection, including skin and nail lesions, before treatment with TNF-alpha inhibitors and during traditional psoriasis treatment. When atypical presentation together with treatment failure is noted in psoriasis patients prescribed biologics, clinicians should investigate evidence of dermatophyte infection and provide proper treatment. Sometimes, multiple skin biopsies and tissue fungal cultures are required to establish a correct diagnosis.

Wnt pathway activation and ABCB1 expression account for attenuation of proteasome inhibitor-mediated apoptosis in multidrug-resistant cancer cells.

Multiple drug resistance (MDR) is a major obstacle to attenuating the effectiveness of chemotherapy to many human malignancies. Proteasome inhibition induces apoptosis in a variety of cancer cells and is recognized as a novel anticancer therapy approach. Despite its success, some multiple myeloma patients are resistant or become refractory to ongoing treatment by bortezomib suggesting that chemoresistant cancer cells may have developed a novel mechanism directed against the proteasome inhibitor. The present study aimed to investigate potential mechanism(s) of attenuation in a MDR cell line, MES-SA/Dx5. We found that compared to the parental human uterus sarcoma cell line MES-SA cells, MES-SA/Dx5 cells highly expressed the ABCB1 was more resistant to MG132 and bortezomib, escaping the proteasome inhibitor-induced apoptosis pathway. The resistance was reversed by co-treatment of MG132 and the ABCB1 inhibitor verapamil. The data indicated that ABCB1 might play a role in the efflux of MG132 from the MES-SA/Dx5 cells to reduce MG132-induced apoptosis. Furthermore, the canonical Wnt pathway was found activated only in the MES-SA/Dx5 cells through active ß-catenin and related transactivation activities. Western blot analysis demonstrated that Wnt-targeting genes, including c-Myc and cyclin D1, were upregulated and were relevant in inhibiting the expression of p21 in MES-SA/Dx5 cells. On the other hand, MES-SA cells expressed high levels of p21 and downregulated cyclin D1 and caused cell cycle arrest. Together, our study demonstrated the existence and participation of ABCB1 and the Wnt pathway in an MDR cell line that attenuated proteasome inhibitor-induced apoptosis.

Intradimer/Intermolecular interactions suggest autoinhibition mechanism in endophilin A1.

Endophilin A1 is a homodimeric membrane-binding endocytic accessory protein with a high dimerization affinity. Its function has been hypothesized to involve autoinhibition. However, the autoinhibition mechanism, as well as the physicochemical basis for the high dimerization affinity of endophilin in solution, have remained unclear. In this contribution, we use a Förster resonance energy transfer (FRET) method to investigate the homodimerization mechanism and intradimer molecular interactions in endophilin. For the endophilin N-BAR domain (which lacks the SH3 domain including a linker region of the full length protein), we observe a large temperature dependence of the dimerization affinity and dimer dissociation kinetics, implying large dimerization enthalpy and dissociation activation enthalpy, respectively. Our evaluation of the protein concentration dependence of dimer dissociation kinetics implies that endophilin reversibly forms monomers via a dissociation/reassociation mechanism. Furthermore, we use a kinetic method that allows us to compare the dissociation kinetics of full-length endophilin to that of truncated mutants. We find that mutants that lack either H0 helix or SH3 domain show significantly faster dissociation kinetics relative to full-length endophilin. This observation supports the presence of an intradimer, intermonomer cross-interaction between H0 helix and SH3 domain from different subunits within a homodimer. Because the H0 helix is known to play a significant role in endophilin's membrane interactions, our measurements support a syngergistic model where these interactions are inhibited in the absence of SH3 domain binding ligands such as dynamin's prolin rich domains, and where the binding of these ligands may be suppressed for non-membrane-bound endophilin.

Curvature sorting of peripheral proteins on solid-supported wavy membranes.

Cellular membrane deformation and the associated redistribution of membrane-bound proteins are important aspects of membrane function. Current model membrane approaches for studying curvature sensing are limited to positive curvatures and often require complex and delicate experimental setups. To overcome these challenges, we fabricated a wavy substrate by imposing a range of curvatures onto an adhering lipid bilayer membrane. We examined the curvature sorting of several peripheral proteins binding to the wavy membrane and observed them to partition into distinct regions of curvature. Furthermore, single-molecule imaging experiments suggested that the curvature sensing of proteins on low-curvature substrates requires cooperative interactions.

Ligand mobility modulates immunological synapse formation and T cell activation.

T cell receptor (TCR) engagement induces clustering and recruitment to the plasma membrane of many signaling molecules, including the protein tyrosine kinase zeta-chain associated protein of 70 kDa (ZAP70) and the adaptor SH2 domain-containing leukocyte protein of 76 kDa (SLP76). This molecular rearrangement results in formation of the immunological synapse (IS), a dynamic protein array that modulates T cell activation. The current study investigates the effects of apparent long-range ligand mobility on T cell signaling activity and IS formation. We formed stimulatory lipid bilayers on glass surfaces from binary lipid mixtures with varied composition, and characterized these surfaces with respect to diffusion coefficient and fluid connectivity. Stimulatory ligands coupled to these surfaces with similar density and orientation showed differences in their ability to activate T cells. On less mobile membranes, central supramolecular activation cluster (cSMAC) formation was delayed and the overall accumulation of CD3ζ at the IS was reduced. Analysis of signaling microcluster (MC) dynamics showed that ZAP70 MCs exhibited faster track velocity and longer trajectories as a function of increased ligand mobility, whereas movement of SLP76 MCs was relatively insensitive to this parameter. Actin retrograde flow was observed on all surfaces, but cell spreading and subsequent cytoskeletal contraction were more pronounced on mobile membranes. Finally, increased tyrosine phosphorylation and persistent elevation of intracellular Ca(2+) were observed in cells stimulated on fluid membranes. These results point to ligand mobility as an important parameter in modulating T cell responses.

An unusual complication related to acupuncture point catgut embedding treatment of obesity.

Treatment of obesity by embedding catgut in acupuncture points has a satisfactory therapeutic effect in many patients. Even though results of its effectiveness are mixed, serious complications are rarely reported with this Chinese traditional therapy. Here an unusual complication of the treatment is reported: multiple tender subcutaneous nodules developed where the catgut was embedded over the lower abdomen and both medial thighs 1 month after treatment. Clinicians should be alert to this possible cause of a rather strange presenting physical sign.

Spatial association of signaling proteins and F-actin effects on cluster assembly analyzed via photoactivation localization microscopy in T cells.

Recognition of antigens by T cell receptors (TCRs) triggers cellular signaling cascades initiated by recruitment to the plasma membrane of numerous effector molecules to form signaling microclusters (MCs). Here we show that the method of high-resolution photoactivation localization microscopy (PALM) imaging can be used to analyze the spatial correlation between kinase ZAP70 and adaptor SLP76 MCs at the cell periphery and the effects of F-actin on MC assembly. We first determined the photophysical rate constants of Dronpa and tdEos fluorescence probes, which allowed us to optimize our dual-color PALM imaging method. We next analyzed the degrees of spatial association through determination of Mander's colocalization coefficients from PALM images, which revealed increasing spatial segregation of ZAP70 and SLP76 MCs at the cell periphery after initiation of signaling. We showed that this spatial segregation at the cell periphery occurred in parallel with the reduction of MC phosphorylation levels. Furthermore, we used Ripley's K function to analyze spatial randomness, and determined average radii of clusters as a function of activation time. The average radii of SLP76 and LAT MCs were found to decrease, whereas ZAP70 MC radii remained relatively constant. Finally, effects of F-actin depolymerization on MC morphology were studied by determining radial distributions of cluster circularity. Our data suggest that MC morphology is affected by actin polymerization. The quantitative analysis of sub-diffraction PALM images may provide a starting point for a molecular interpretation of cluster-cluster interactions and of the regulation of T cell signaling MCs by the cytoskeleton.

Independent and cooperative roles of adaptor molecules in proximal signaling during FcepsilonRI-mediated mast cell activation.

Activation through FcepsilonRI, a high-affinity IgE-binding receptor, is critical for mast cell function during allergy. The formation of a multimolecular proximal signaling complex nucleated by the adaptor molecules SLP-76 and LAT1 is required for activation through this receptor. Based on previous T-cell studies, current dogma dictates that LAT1 is required for plasma membrane recruitment and function of SLP-76. Unexpectedly, we found that the recruitment and phosphorylation of SLP-76 were preserved in LAT1(-/-) mast cells and that SLP-76(-/-) and LAT1(-/-) mast cells harbored distinct functional and biochemical defects. The LAT1-like molecule LAT2 was responsible for the preserved membrane localization and phosphorylation of SLP-76 in LAT1(-/-) mast cells. Although LAT2 supported SLP-76 phosphorylation and recruitment to the plasma membrane, LAT2 only partially compensated for LAT1-mediated cell signaling due to its decreased ability to stabilize interactions with phospholipase Cgamma (PLCgamma). Comparison of SLP-76(-/-) LAT1(-/-) and SLP-76(-/-) mast cells revealed that some functions of LAT1 could occur independently of SLP-76. We propose that while SLP-76 and LAT1 depend on each other for many of their functions, LAT2/SLP-76 interactions and SLP-76-independent LAT1 functions also mediate a positive signaling pathway downstream of FcepsilonRI in mast cells.

Type I collagen-functionalized supported lipid bilayer as a cell culture platform.

The supported phospholipid bilayer serves as an important biomimetic model for the cell membrane in both basic and applied scientific research. We have constructed a biomimetic platform based on a supported phospholipid bilayer that is functionalized with type I collagen to serve as a substrate for cell culture. To create the type I collagen-functionalized lipid bilayer assembly, a simple chemical approach was employed: lipid vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(glutaryl) (DP-NGPE), a carboxylic acid-functionalized phospholipid, were prepared and then fused onto an SiO(2) substrate to form a supported lipid bilayer. Subsequently, type I collagen molecules were introduced to form stable collagen-lipid conjugates via amide linkages with activated DP-NGPE lipids. The binding kinetics of the conjugation process and the resultant changes in film thickness and viscoelasticity were followed using the quartz crystal microbalance with dissipation (QCM-D) monitoring. The morphology of the conjugated collagen adlayer was investigated with atomic force microscopy (AFM). We observed that the adsorbed collagen molecules tended to self-assemble into fibrillar structures. Fluorescence recovery after photobleaching (FRAP) was utilized to estimate lateral lipid mobility, which was reduced by up to 20% after the coupling of type I collagen to the underlying lipid bilayer. As a cell culture platform, the collagen-conjugated supported lipid bilayer showed promising results. Smooth muscle cells (A10) retained normal growth behavior on the collagen-functionalized platform, unlike the bare POPC lipid bilayer and the POPC/DG-NGPE bilayer without collagen. The biomimetic functionalized lipid system presented here is a simple, yet effective approach for constructing a cell culture platform to explore the interactions between extracellular matrix components and cells.

Antigen-driven bystander effect accelerates epicutaneous sensitization with a new protein allergen.

Exposure to protein allergen epicutaneously, inducing a Th2-dominant immune response, sensitizes the host to the development of atopic disease. Antigen-driven bystander effect demonstrates that polarized T cells could instruct naïve T cells to differentiate into T cells with similar phenotype. In this study, we aimed to determine the contribution of antigen-driven bystander effect on epicutaneous sensitization with a newly introduced protein allergen. BALB/c mice were immunized intraperitoneally with BSA emulsified in alum, known to induce a Th2 response, three weeks before given BSA and OVA epicutaneously. Lymph node cells from these mice restimulated with OVA secreted higher levels IL-4, IL-5 and IL-13 as compared with cells from mice without BSA immunization. In addition, BALB/c mice immunized subcutaneously with BSA emulsified in complete Freund's adjuvant, known to induce a Th1-predominant response, also induced higher Th1 as well as Th2 cytokine response when restimulated with OVA as compared with mice without immunization. We demonstrated that subcutaneous immunization with BSA in CFA induced Th2 as well as Th1 response. The threshold of epicutaneous sensitization to OVA was also reduced, possibly due to increased expressions of IL-4 and IL-10 in the draining lymph nodes during the early phase of sensitization. In conclusion, antigen-driven bystander effect, whether it is of Th1- or Th2-predominant nature, can accelerate epicutaneous sensitization by a newly introduced protein allergen. These results provide a possible explanation for mono- to poly-sensitization spread commonly observed in atopic children.

Low-energy visible light irradiation modulates immune responses induced by epicutaneous sensitization with protein antigen.

Epicutaneous sensitization has been an important route for protein allergen sensitization in atopic disease. Although the skin is irradiated by sunlight daily, the influence of visible light on epicutaneous sensitization has not been explored. In this study, by using a well-established murine protein-patch model, we show that low-energy visible light (LEVL) irradiation could differentially modulate the predominant Th2 immune response induced by epicutaneous sensitization with protein antigen. When the induced Th2 response was strong, as usually observed in BALB/c mice, LEVL irradiation suppressed the response. In contrast, LEVL irradiation enhanced the weaker Th2 response in C57BL/6 mice. Increased IL-18 and decreased TGF-beta expression in draining lymph nodes after LEVL irradiation was observed in BALB/c mice, but not in C57BL/6 mice. LEVL irradiation also enhanced IL-18 expression in skin and reduced the downregulation of CD24 expression on epidermal Langerhans cells in draining lymph nodes of BALB/c mice. Collectively, these results provide evidence for immunomodulatory effects of LEVL irradiation and will help us develop a useful strategy for prevention of allergen sensitization.

Epicutaneous sensitization with a protein antigen induces Th17 cells.

BACKGROUND: Th17 is a newly identified effector T cell lineage which plays a central role in many human inflammatory diseases and experimental animal models. Epicutaneous sensitization with a protein antigen has been proven to induce a Th2-predominant immune response and lead to development of atopic diseases in a murine protein-patch model. OBJECTIVE: We sought to assess the generation of Th17 cells in epicutaneous sensitization with a protein antigen and its regulation by environmental elements and genetic background. METHODS: BALB/c, C57BL/6, and DO11.10 mice were epicutaneously immunized by patch application of the following: ovalbumin alone, or co-administration of one of TLR ligands, irritant, hapten or superantigens. IL-17 and IL-22 contents in supernatants of in vitro reactivation culture of lymph nodes cells were determined by ELISA. Frequency of IL-17-secreting CD4 T cells was measured by ELISPOT. RESULTS: Small but significant amounts of IL-17 and IL-22 could be detected in supernatants of in vitro reactivation culture of lymph nodes cells of mice receiving patch application of ovalbumin. ELISPOT assay for IL-17 also revealed low frequency of IL-17-secreting CD4 T cells in lymph nodes cells in ovalbumin group. All TLR ligands tested including agonists for TLR2, TLR3, TLR4, TLR5, TLR7 and TLR9 as well as many environmental elements including irritant, hapten and superantigen could further promote the generation of Th17 cells. In addition, C57BL/6 mice generate less Th17 cells than BALB/c mice in epicutaneous sensitization. CONCLUSION: This study demonstrates Th17 generation and its regulation by environmental elements and genetic background to a protein antigen by epicutaneous route.

Self-assembly of dermal papilla cells into inductive spheroidal microtissues on poly(ethylene-co-vinyl alcohol) membranes for hair follicle regeneration.

Self-aggregation is key to hair follicle (HF) induction ability of dermal papilla (DP) cells and neogenesis of HF can be achieved by transplanting DP microtissues. However, there is currently lack of a suitable system that allows efficient production of DP microtissues and analysis of DP self-aggregation in vitro. We demonstrate that, at a higher seeding cell density, poly(ethylene-co-vinyl alcohol) (EVAL) membranes facilitate DP self-assembly into many compact spheroidal microtissues that are able to induce new HFs. This self-assembling process is associated with an enhanced cell movement and a declined cell-substrate adhesivity on EVAL. A compromised cell growth is also revealed on EVAL. On the contrary, a more adherent surface allows faster cell expansion but maintains DP cells in a flat morphology. Dynamically, cell migration, intercellular collision and intercellular adhesion contribute to DP microtissue formation on EVAL. Our results suggest that, for large-scale production of DP microtissues for HF regeneration, an adhesive surface is needed for quick cell expansion and a biomaterial with a lower adhesivity is required for self-aggregation. In addition, this system can be a model for investigation of DP self-aggregation in vitro.