Biology subjects

Maki, K.

Publications and source records attributed to Maki, K..

4 recordsLinked to original sources

bioRxiv2025

Distinct dermal fibroblasts direct mechano-chemical signaling to the epidermis during pregnancy

Dermal fibroblasts alter extracellular matrix (ECM) and tissue mechanics dynamically in wound healing and fibrosis, however, are understudied in healthy skin remodeling across life stages. Here, by conducting spatio-temporal transcriptomics, we identified Cdh4+ dermal fibroblast subpopulation that remodels ECM and converts mechano-to-chemical signals to promote epidermal stem cell proliferation in expanding abdominal skin of pregnant mice. Mechanistically, Cdh4+ fibroblasts produce a pregnancy-responsive matrisome, resulting in denser and stiffer dermal fibrils. These fibroblasts then sense the stiffened substrate and convert the mechanical input into a chemical output via the YAP1-TGF{beta}2 axis, leading to the proliferation of epidermal stem cells via TGF{beta} receptor in the expanding skin. Thus, Cdh4+ fibroblasts fine-tune the dermal mechanofield and act as a mechanical-to-chemical signal conversion hub in healthy skin expansion.

developmental biology↗

bioRxiv2023

Sclerostin modulates the degree of mineralization and the stiffness profile of the fibrocartilaginous enthesis for mechanical tissue integrity

Fibrocartilaginous entheses consist of four graded tissue layers including tendon, the unmineralized and mineralized fibrocartilage, and subchondral bone with varying degrees of stiffness. Here we examined the functional role of sclerostin that is expressed in mature mineralized fibrochondrocytes. Following rapid mineralization of the unmineralized fibrocartilage and parallel replacement of epiphyseal hyaline cartilage by bone, the unmineralized fibrocartilage re-expanded after a decline in alkaline phosphatase activity at the mineralization front. Sclerostin was co-expressed with osteocalcin in the bottom of the mineralized fibrocartilage adjacent to subchondral bone. In Scx deficient mice with less mechanical loading due to defects of the Achilles tendon, the number of sclerostin+ fibrochondrocytes was significantly reduced in the defective enthesis where chondrocyte maturation was markedly impaired in both fibrocartilage and hyaline cartilage. Loss of the Sost gene, coding for sclerostin, caused increased mineral density in the mineralized zones of the fibrocartilaginous enthesis. Atomic force microscopy analysis revealed the higher stiffness of fibrocartilage. These lines of evidence suggest that sclerostin in mature mineralized fibrochondrocytes acts as a modulator for mechanical tissue integrity of the fibrocartilaginous enthesis.

developmental biology↗

bioRxiv2023

Cyclic mechanical stretching stimuli promotes angiocrine signals during in vitro liver bud formation from human pluripotent stem cells

Liver organoids derived from human pluripotent stem cells (hPSCs) allow elucidation of liver development and have great potential for drug discovery. However, current methods for generating liver organoids using biochemical substances do not realize the vascular network of the liver lobule, due to the lack of knowledge of the role of in vivo mechanical environments during liver development. Here, we investigate the role of cyclic mechanical stretch (cMS) to angiocrine signals of hepatoblasts (HBs) and endothelial progenitor cells (EPCs) using an organ-on-a-chip platform to emulate in vivo-like mechanical environments and hPSCs to recapitulate hepatic differentiation. RNA sequencing revealed that the expression of angiocrine signal genes, such as HGF and matrix metallopeptidase 9 (MMP9), was increased by cMS in co-cultured HBs and EPCs. The secretion of HGF and MMP9 increased by 3.23-folds and 3.72-folds with cMS in the co-cultured HBs and EPCs but was not increased by cMS in the mono-cultured HBs and EPCs. Immunofluorescence micrographs with anti-KRT19, HGF, and MMP9 antibodies also revealed that cMS increased HGF and MMP9 expression when HBs and EPCs were co-cultured. cMS increased HGF and MMP9 expression and secretion when HBs and EPCs were co-cultured. Our findings provide new insights into the mechanical factors involved in the vascular network of human liver bud formation and liver organoid generation.

bioengineering↗

bioRxiv2019

Combined use of design of experiments and metabolic engineering for optimization of nogalamycin production

Nogalamycin is an anthracycline antibiotic produced from Streptomyces nogalater that exerts its mechanism of action via inhibition of topoisomerase I. Nogalamycin has a unique tetracyclic structure composed of a 7-O-glycosidically linked L-nogalose sugar and a C2-C5\"-linked L-nogalamine residue that forms an epoxyoxacin ring. Nogalamycin was originally developed as an anticancer agent in the 1970s, however, it exhibited dose-limiting cardiotoxicity. Shortly after the discovery of nogalamycin, the semi-synthetic analogue 7-O-methylnogarol, or menogaril, was synthesized and exhibited a mild improvement in cardiotoxicity and anticancer efficacy. Menogaril lacks the 7-O-L-nogalose moiety and functions as a topoisomerase II inhibitor, like most anthracyclines, however this agent still proved too toxic for clinical use. Our laboratory is developing a production platform for microbial synthesis of novel nogalamycin analogs useful for treatment of human cancers or as antibiotics. Our initial hypothesis is that overexpression of structural genes responsible for synthesis of TDP-deoxysugar and polyketide precursor substrates, respectively, will increase carbon flux towards nogalamycin production. In this study, we have employed metabolic engineering to enhance nogalamycin production in Streptomyces nogalater. In this work, we used an optimized soytone glucose production medium to produce nogalamycin. We also overexpressed copies of structural biosynthetic genes to bolster substrate precursor building blocks for nogalamycin production. First, overexpression of the TDP-glucose synthase and TDP-D-glucose-4,6-dehydratase enzymes (mtmDE) resulted in a 50% increase in nogalamycin production (160 mg/L) as compared to wildtype S. nogalater (100 mg/L). Secondly, overexpression of the minimal polyketide synthase genes (snoa123) resulted in a fourfold production increase in nogalamycin (400 mg/L). This production platform will serve as the fundament for production of nogalamycin analogues for future drug development efforts.

microbiology↗