Browsing by Author "Ho, Ping-Chih"

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alpha-ketoglutarate orchestrates macrophage activation through metabolic and epigenetic reprogramming
(2017-09-01)
Liu, Pu-Ste
;
Wang, Haiping
;
Li, Xiaoyun
;
Chao, Tung
;
Teav, Tony
Glutamine metabolism provides synergistic support for macrophage activation and elicitation of desirable immune responses; however, the underlying mechanisms regulated by glutamine metabolism to orchestrate macrophage activation remain unclear. Here we show that the production of alpha-ketoglutarate (alpha KG) via glutaminolysis is important for alternative (M2) activation of macrophages, including engagement of fatty acid oxidation (FAO) and Jmjd3-dependent epigenetic reprogramming of M2 genes. This M2-promoting mechanism is further modulated by a high alpha KG/succinate ratio, whereas a low ratio strengthens the proinflammatory phenotype in classically activated (M1) macrophages. As such, aKG contributes to endotoxin tolerance after M1 activation. This study reveals new mechanistic regulations by which glutamine metabolism tailors the immune responses of macrophages through metabolic and epigenetic reprogramming.
Tape-Stripping Electrochemical Detection of Melanoma
(2019-10-15)
Darvishi, Sorour
;
Pick, Horst
;
Lin, Tzu-En
;
Zhu, Yingdi
;
Li, Xiaoyun
A noninvasive electrochemical melanoma detection approach based on using adhesive tapes for collecting and fixing cells from a suspicious skin area and transferring the cells into a scanning electrochemical microscope (SECM) is presented. The adhesive layer collects the cells reproducibly and keeps them well adhered on the tape during experiments in an electrolyte solution. A melanoma biomarker, here the intracellular enzyme tyrosinase (TYR), was imaged on the tape-collected cells without further cell lysing using antibodies that were labeled with horseradish peroxidase (HRP). The HRP labels catalyzed the oxidation of a dissolved redox-active species, which was detected at a soft microelectrode, gently brushed in contact mode over the tape. The melanoma biomarker was first detected on tape-stripped samples with murine melanoma cells of different concentrations. Thereafter, increasing levels of TYR were recorded in cells that were collected from the skin of melanoma mouse models representing three different stages of tumor growth. Additionally, SECM results of tape-stripped different human melanoma cell lines were confirmed by previous studies based on traditionally fixed and permeabilized cells.