Simple Analysis of Lipid Inhibition Activity on an Adipocyte Micro-Cell Pattern Chip

Facile and Rapid Microcontact Printing of Additive-Free Polydimethylsiloxane for Biological Patterning Diversity

The development and application of micropatterning technology play a promising role in the manipulation of biological substances and the exploration of life sciences at the microscale. However, the universally adaptable micropatterning method with user-friendly properties for acceptance in routine laboratories remains scarce. Herein, a green, facile, and rapid microcontact printing method is reported for upgrading popularization and diversification of biological patterning. The three-step printing can achieve high simplicity and fidelity of additive-free polydimethylsiloxane (PDMS) micropatterning and chip fabrication within 8 min as well as keep their high stability and diversity. A detailed experimental report is provided to support the advanced microcontact printing method. Furthermore, the applications of easy-to-operate PDMS-patterned chips are extensively validated to complete microdroplet array assembly with spatial control, cell pattern formation with high efficiency and geometry customization, and microtissue assembly and biomimetic tumor construction on a large scale. This straightforward method promotes diverse micropatternings with minimal time, effort, and expertise and maximal biocompatibility, which might broaden its applications in interdisciplinary scientific communities. This work also offers an insight into the establishment of popularized and market-oriented microtools for biomedical purposes such as biosensing, organs on a chip, cancer research, and bioscreening.

Biofabrication of vascularized adipose tissues and their biomedical applications

Recent advances in adipose tissue engineering and cell biology have led to the development of innovative therapeutic strategies in regenerative medicine for adipose tissue reconstruction. To date, the many in vitro and in vivo models developed for vascularized adipose tissue engineering cover a wide range of research areas, including studies with cells of various origins and types, polymeric scaffolds of natural and synthetic derivation, models presented using decellularized tissues, and scaffold-free approaches. In this review, studies on adipose tissue types with different functions, characteristics and body locations have been summarized with 3D in vitro fabrication approaches. The reason for the particular focus on vascularized adipose tissue models is that current liposuction and fat transplantation methods are unsuitable for adipose tissue reconstruction as the lack of blood vessels results in inadequate nutrient and oxygen delivery, leading to necrosis in situ. In the first part of this paper, current studies and applications of white and brown adipose tissues are presented according to the polymeric materials used, focusing on the studies which could show vasculature in vitro and after in vivo implantation, and then the research on adipose tissue fabrication and applications are explained.

Caffeic and Chlorogenic Acids Synergistically Activate Browning Program in Human Adipocytes: Implications of AMPK- and PPAR-Mediated Pathways

Caffeic acid (CA) and chlorogenic acid (CGA) are phenolic compounds claimed to be responsible for the metabolic effects of coffee and tea consumption. Along with their structural similarities, they share common mechanisms such as activation of the AMP-activated protein kinase (AMPK) signaling. The present study aimed to investigate the anti-obesity potential of CA and CGA as co-treatment in human adipocytes. The molecular interactions of CA and CGA with key adipogenic transcription factors were simulated through an in silico molecular docking approach. The expression levels of white and brown adipocyte markers, as well as genes related to lipid metabolism, were analyzed by real-time quantitative PCR and Western blot analyses. Mechanistically, the CA/CGA combination induced lipolysis, upregulated AMPK and browning gene expression and downregulated peroxisome proliferator-activated receptor γ (PPARγ) at both transcriptional and protein levels. The gene expression profiles of the CA/CGA-co-treated adipocytes strongly resembled brown-like signatures. Major pathways identified included the AMPK- and PPAR-related signaling pathways. Collectively, these findings indicated that CA/CGA co-stimulation exerted a browning-inducing potential superior to that of either compound used alone which merits implementation in obesity management. Further, the obtained data provide additional insights on how CA and CGA modify adipocyte function, differentiation and lipid metabolism.

Molecular Characterization of a Novel Cold-Active Hormone-Sensitive Lipase (HaHSL) from Halocynthiibacter Arcticus

Bacterial hormone-sensitive lipases (bHSLs), which are homologous to the catalytic domains of human HSLs, have received great interest due to their uses in the preparation of highly valuable biochemicals, such as drug intermediates or chiral building blocks. Here, a novel cold-active HSL from Halocynthiibacter arcticus (HaHSL) was examined and its enzymatic properties were investigated using several biochemical and biophysical methods. Interestingly, HaHSL acted on a large variety of substrates including tertiary alcohol esters and fish oils. Additionally, this enzyme was highly tolerant to high concentrations of salt, detergents, and glycerol. Furthermore, immobilized HaHSL retained its activity for up to six cycles of use. Homology modeling suggested that aromatic amino acids (Trp²³, Tyr⁷⁴, Phe⁷⁸, Trp⁸³, and Phe²⁴⁵) in close proximity to the substrate-binding pocket were important for enzyme activity. Mutational analysis revealed that Tyr⁷⁴ played an important role in substrate specificity, thermostability, and enantioselectivity. In summary, the current study provides an invaluable insight into the novel cold-active HaHSL from H. arcticus, which can be efficiently and sustainably used in a wide range of biotechnological applications.