Gut-liver microphysiological systems revealed potential crosstalk mechanism modulating drug metabolism

The small intestine and liver play important role in determining oral drug's fate. Both organs are also interconnected through enterohepatic circulation, which imply there are crosstalk through circulating factors such as signaling molecules or metabolites that may affect drug metabolism. Coculture of hepatocytes and intestinal cells have shown to increase hepatic drug metabolism, yet its crosstalk mechanism is still unclear. In this study, we aim to elucidate such crosstalk by coculturing primary human hepatocytes harvested from chimeric mouse (PXB-cells) and iPSc-derived intestinal cells in a microphysiological systems (MPS). Perfusion and direct oxygenation from the MPS were chosen and confirmed to be suitable features that enhanced PXB-cells albumin secretion, cytochrome P450 (CYP) enzymes activity while also maintaining barrier integrity of iPSc-derived intestine cells. Results from RNA-sequencing showed significant upregulation in gene ontology terms related to fatty acids metabolism in PXB-cells. One of such fatty acids, arachidonic acid, enhanced several CYP enzyme activity in similar manner as coculture. From the current evidences, it is speculated that the release of bile acids from PXB-cells acted as stimuli for iPSc-derived intestine cells to release lipoprotein which was ultimately taken by PXB-cells and enhanced CYP activity.

Enhanced restoration of in situ-damaged hairs by intradermal transplantation of trichogenous dermal cells

We developed a nude rat model for determining the capacity of trichogenous cells to restore in vivo-damaged hair follicles (HFs). A surgical scalpel was inserted into the rat's dermis to generate the in vivo-damaged pelage HFs, the HFs whose lower parts were lost, but the upper parts containing sebaceous and bulge regions remained intact. Dermal papilla cells (DPCs) and dermal sheath cells (DSCs) from EGFP transgenic rat vibrissae were propagated in culture, and each alone (DPC or DSC) or a mixture (DPC/DSC) was transplanted into the intradermal path made by a scalpel. It was found that the in vivo-damaged HFs had hair self-restoration ability, and the transplanted trichogenic dermal cells prominently enhanced this ability, DPC/DSC transplants being more effective in enhancement than DPC or DSC alone. The restored bulbs contained EGFP-positive cells, shed their original straight shafts, generated new shafts, and further developed into hairs with a sebaceous gland and bulge structures by ~6 weeks post-transplantation. Compared to the preceding animal models, this model is less invasive, requires fewer donor cells and allows repeated operations with higher reproducibility and accuracy. The present study suggests that conditions causing in situ-damaged HFs, such as androgenic alopecia, in which HFs are damaged and miniaturized, can be restored by functional trichogenous dermal cell transplantation therapy. Copyright © 2015 John Wiley & Sons, Ltd.

Restorative effect of hair follicular dermal cells on injured human hair follicles in a mouse model

No model is available for examining whether in vivo-damaged human hair follicles (hu-HFs) are rescued by transplanting cultured hu-HF dermal cells (dermal papilla and dermal sheath cells). Such a model might be valuable for examining whether in vivo-damaged hu-HFs such as miniaturized hu-HFs in androgenic alopecia are improvable by auto-transplanting hu-HF dermal cells. In this study, we first developed mice with humanized skin composed of hu-keratinocytes and hu-dermal fibroblasts. Then, a 'humanized scalp model mouse' was generated by transplanting hu-scalp HFs into the humanized skin. To demonstrate the usability of the model, the lower halves of the hu-HFs in the model were amputated in situ, and cultured hu-HF dermal cells were injected around the amputated area. The results demonstrated that the transplanted cells contributed to the restoration of the damaged HFs. This model could be used to explore clinically effective technologies for hair restoration therapy by autologous cell transplantation.

Embryonic dermal condensation and adult dermal papilla induce hair follicles in adult glabrous epidermis through different mechanisms

Hair induction in the adult glabrous epidermis by the embryonic dermis was compared with that by the adult dermis. Recombinant skin, composed of the adult sole epidermis and the embryonic dermis containing dermal condensations (DC), was transplanted onto the back of nude mice. The epidermis of transplants formed hairs. Histology on the induction process demonstrated the formation of placode-like tissues, indicating that the transplant produces hair follicles through a mechanism similar to that underlying hair follicle development in the embryonic skin. An isolated adult rat sole skin piece, inserted with either an aggregate of cultured dermal papilla (DP) cells or an intact DP between its epidermis and dermis, was similarly transplanted. The transplant produced hair follicles. Histology showed that the epidermis in both cases surrounded the aggregates of DP cells. The epidermis never formed placode-like tissues. Thus, it was concluded that the adult epidermal cells recapitulate the embryonic process of hair follicle development when exposed to DC, whereas they get directly into the anagen of the hair cycle when exposed to DP. The expression pattern of Edar and Shh genes, and P-cadherin protein during the hair follicle development in the two types of transplants supported the above conclusion.

In vitro reconstruction of a three-dimensional middle ear mucosal organ and its in vivo transplantation

CONCLUSIONS

These experimental findings suggest the feasibility of artificial middle ear mucosa grafting as an effective treatment for achieving mucosal regeneration after middle ear surgery.

OBJECTIVES

Postoperative mucosal regeneration of tympanic cavity and mastoid cavity is of great importance after middle ear surgery. We reconstructed in vitro a three-dimensional middle ear mucosal organ, and assessed its feasibility for regenerative medicine of middle ear-related diseases.

MATERIALS AND METHODS

Epithelial cells and fibroblasts were isolated from the middle ear mucosa of rats and propagated by subculturing. An artificial middle ear mucosal organ was reconstructed by overlaying the middle ear epithelial cells on three-dimensional lattices of a collagen gel that had been repopulated with the fibroblasts. In addition, the artificial organ was implanted in the middle ear cavity of rats.

RESULTS

The artificial middle ear mucosa consisted of the single layer of epithelial cells, the basal membrane, and the underlying connective tissue. Electron microscopy revealed the presence of tight junctions and adherence junctions on the apical side, and adhesion complexes made of desmosomes. The reconstituted mucosa expressed genes of mucin, strongly suggesting that the artificial middle ear mucosa was capable of secreting mucus proteins. The DiI-labeled artificial middle ear mucosa implanted into the middle ear cavity was well engrafted and associated with host tissues.

Mapping of phosphorylated proteins on two-dimensional polyacrylamide gels using protein phosphatase

This study developed an enzymatic method for high-throughput mapping of phosphoproteins on two-dimensional (2-D) polyacrylamide gels. Proteins of cultured rat skin fibroblasts were divided into two aliquots, one of which was dephosphorylated using recombinant lambda protein phosphatase and the other was not treated with the enzyme. The two aliquots were then subjected to 2-D electrophoresis. Phosphoproteins could be mapped on the 2-D gel of the nontreated aliquot by comparing the gels of the two aliquots, because the phosphoproteins in the treated aliquot shifted to more basic positions on the gel. This technique revealed that approximately 5% of the detectable proteins were phosphorylated. Fourteen phosphoproteins were identified by mass spectrometry, including proteasome component C8 and small glutamine-rich tetratricopeptide repeat-containing protein. Furthermore, the extent of phosphorylation of two actin modulating proteins, destrin and cofilin, was found to be significantly reduced when the cells were chemically or enzymatically detached from the culture dishes. The method developed by this study can generally be applied to all biological materials and is useful for high-throughput mapping of phosphoproteins in proteome research.

Kdap, a novel gene associated with the stratification of the epithelium

The skin develops and differentiates during embryogenesis, which is concertedly regulated by a variety of genes. The present study isolated from the rat embryonic skin a novel differentiation-associated gene named Kdap (keratinocyte differentiation-associated protein) by suppression subtractive hybridization between the skin of 14day postcoitus (dpc) embryo (the prehair-germ stage) and that of 17dpc embryo (the hair-germ stage). Its mRNA contained four spliced forms in these tissues. The gene encoded a protein of total 98 amino acids with a calculated molecular mass of 11kDa and an isoelectric point of 6.1 as an unspliced form. The two splicing zones were well conserved among rat, mouse, and human. This protein had a high hydrophobic N-terminal region, a possible signal sequence, and contained two putative N-myristoylation sites and two casein kinase II phosphorylation sites. In situ hybridization experiments detected Kdap transcripts exclusively in the suprabasal cell layers of the embryonic epidermis. Intense expression was also seen in suprabasal cells in regions of infundibulum of the hair follicle. These results indicated that Kdap provides a new insight into the mechanism of differentiation and the maintenance of stratified epithelia.

Establishment of rat dermal papilla cell lines that sustain the potency to induce hair follicles from afollicular skin

Dermal papilla cells in culture show a lower proliferative capacity compared with dermal fibroblasts, and lose their in situ potency to induce hair follicles in the epidermis at more than 10 passage numbers. This study overcomes these limitations of cultured papilla cells and for the first time demonstrates that papilla cells can be serially cultured for a long period without losing their hair-inductive potency. Outgrowth and the ensuing proliferation of papilla cells were markedly stimulated when explants of rat vibrissa papillae were cultured with rat sole-derived keratinocytes. Such feeder effects of the keratinocytes could be replaced to some extent with conditioned medium of the cells. Serial cultivation of papilla cells was established by maintaining them in the conditioned medium in which they were subcultured for more than 90 passages with an approximate population doubling time of 30 h, a value similar to that of rat dermal fibroblasts. During the subculture, they showed morphologic characteristics and phenotypic expressions of original papilla cells. Even after at least 70 passages, papilla cells sustained the innate hair follicle inductive ability at a level comparable with that of intact dermal papillae. The established cell lines did not show tumorigenicity when they were subcutaneously implanted into nude mice. The culture method developed in this study should facilitate the search for a biochemical entity of dermal papilla cells.

Elution concentration of proteins cut from two-dimensional polyacrylamide gels using Pasteur pipettes

The present study devised a new procedure for concentrating proteins cut from primary two-dimensional polyacrylamide gels prior to their structural characterization. Gel spots containing a protein were cut from several identical two-dimensional gels and loaded on the top of a high tensile strength stacking gel in a Pasteur pipette. The protein was concentrated electrophoretically into a small volume in the narrow tip of the pipette. The concentrated protein was then blotted from the stacking gel onto a polyvinylidene difluoride membrane, where the protein was subjected to tryptic on-membrane digestion. Utilizing this system, we identified 22 proteins chosen randomly from two-dimensional gels of proteins from rat dermal papilla cells by internal microsequencing. As much as 1.5 mL volume (cut gel spots in protein sample buffer) could be loaded onto the Pasteur pipettes, generally yielding a final on-membrane area of approximately 2 mm2 after elution concentration and electroblotting onto polyvinylidene difluoride membranes. We concluded that this newly devised system is effective and useful for concentrating proteins prior to structural characterization, and that larger volumes than previously recommended can be effectively concentrated, with little or no effect on the final on-membrane area occupied by the concentrated proteins.

The upper dermal sheath has a potential to regenerate the hair in the rat follicular epidermis

It has been established that the dermal papilla and the lower dermal sheath of a hair follicle can induce a new hair bulb in follicular epidermis. However, the upper dermal sheath has been believed not to have such an inductive capacity. In contrast to this generally accepted notion, the present study claims the inductive capacity of the upper dermal sheath of a rat vibrissa follicle, as pelage-type hairs were autonomously produced in the amputated upper halves of the follicles when implanted under the kidney capsule for 8 weeks. The study with monoclonal antibodies specific to different follicular tissues clearly revealed the regeneration of small hair bulbs in these implants and suggested that the fine hairs were formed as a result of the interaction between the upper dermal sheath cells and the follicular basal cells. Newly formed bulbs located at two separate sites, one at the amputated end and the other in the upper region of the follicles. No bulb was formed near the bulge area where follicular stem cells had been reported to locate. However, the possibility of involvement of the stem cells in the bulb formation remains, as migration and rearrangement of epidermal cells had occurred in the implants. Together with the comparative experiments on the inductive potential of various dermal compartments, the present study showed that the upper dermal sheath possesses a hair-inducing ability which is weak, as compared to the lower dermal compartments, but sufficient to induce the follicular epidermis to differentiate into the pelage-like hair-producing bulb, and would be activated only under this specific condition.

A cytotoxic substance from Sangre de Grado

Taspine has been isolated as a cytotoxic substance from Sangre de Grado, sap of Croton palanostigma (Euphorbiaceae), by bioassay guided fractionation. The cytotoxicity (IC50) of taspine was found to be 0.39 microgram/ml against KB cells and 0.17 microgram/ml against V-79 cells.

A quantitative structure-activity relationship for antitumor activity of long-chain phenols from Ginkgo biloba L

With the aim of obtaining compounds with strong antitumor activity, a quantitative structure-activity relationship (QSAR) of antitumor phenolic compounds (long-chain phenols) was derived using the Hansch-Fujita equation. The ED50 values against Chinese hamster V-79 cells were analyzed in terms of log P as the hydrophobic parameter and the energy of the lowest unoccupied molecular orbital (ELUMO) calculated by using the modified neglect of differential overlap (MNDO) method as the electronic parameter, by means of multiple regression analysis. It was found that the activities mainly depended on log P (an optimum log P of 8.3) and a low-lying ELUMO value. 4-Undecylcatechol, selected on the basis of the above results, exhibited strong antitumor activity against Sarcoma 180 ascites and P-388 lymphocytic leukemia.