SSR-LDs

Bioluminescent and fluorescent imaging xenograft models use tumor cells engineered to express optical reporters so tumor engraftment, growth, dissemination, and treatment response can be monitored longitudinally in living animals and validated ex vivo. Bioluminescence imaging usually measures luciferase activity after substrate administration and is commonly used as a surrogate for viable reporter-expressing tumor burden, while fluorescence imaging measures reporter or probe emission and can support tumor localization, ex vivo confirmation, or complementary multimodal analysis.

AMP-activated protein kinase, AMPK, is a conserved cellular energy sensor that responds to reduced cellular energy status and coordinates metabolism by increasing ATP-generating catabolic pathways while suppressing ATP-consuming anabolic processes. In metabolic disease research, the AMPK pathway is experimentally relevant because it regulates hepatic lipid synthesis, fatty acid oxidation, glucose production, skeletal-muscle glucose disposal, mTORC1-linked biosynthesis, autophagy, mitochondrial homeostasis, and whole-body energy balance. The central pathway logic is that energy stress, metformin, exercise-like stimulation, or direct AMPK activators increase AMPKα Thr172 phosphorylation and downstream substrate phosphorylation, including ACC and RAPTOR. Phosphorylation of ACC suppresses lipogenesis and supports fatty acid oxidation, whereas phosphorylation of RAPTOR suppresses mTORC1 signaling and links cellular energy status to growth and protein synthesis control. The pathway is linked

Lipid droplets are intracellular organelles with a neutral-lipid core that stores triacylglycerols and sterol esters, and Oil Red O or Sudan dyes detect these hydrophobic lipid deposits by partitioning into retained lipids in fresh or frozen specimens. Oil Red O stains neutral triglycerides and lipids in frozen tissue sections or air-dried cytologic preparations, while Sudan Black B has also been used as a histochemical fat stain for lipid-rich tissue structures.

Directly induced neuron culture converts somatic cells, most commonly fibroblasts, into induced neurons without passing through a pluripotent or neural progenitor stage; classic evidence shows that mouse fibroblasts can be converted by Ascl1, Brn2/Pou3f2, and Myt1l, human fibroblasts can be converted by defined neuronal transcription factors, and human fibroblasts can also be converted by miR-9/9-124 with neurogenic or subtype-specifying transcription factors. The readout is acquisition of neuronal identity and function, assessed by neuronal morphology, neuronal markers such as Tuj1/βIII-tubulin, MAP2, synapsin, and subtype markers when relevant, together with functional assays such as action-potential firing, synaptic activity, and electrophysiology.