Glycogen synthase kinase-3β (GSK-3β), a serine/threonine protein kinase, has been reported to show essential roles in molecular pathophysiology of many diseases. Mitochondrion is a dynamic organelle for producing cellular energy and determining cell fates. Stress-induced translocated GSK-3β may interact with mitochondrial proteins, including PI3K-Akt, PGC-1α, HK II, PKCε, components of respiratory chain, and subunits of mPTP. Mitochondrial pool of GSK-3β has been implicated in mediation of mitochondrial functions. GSK-3β exhibits the regulatory effects on mitochondrial biogenesis, mitochondrial bioenergetics, mitochondrial permeability, mitochondrial motility, and mitochondrial apoptosis. The versatile functions of GSK-3β might be associated with its wide range of substrates. Accumulative evidence demonstrates that GSK-3β inactivation may be potentially developed as the promising strategy in management of many diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). Intensive efforts have been made for exploring GSK-3β inhibitors. Natural products provide us a great source for screening new lead compounds in inactivation of GSK-3β. The key roles of GSK-3β in mediation of mitochondrial functions are discussed in this review.
Nobiletin (NOB) chemically known as 5,6,7,8,3′,4′-hexamethoxyflavone is a dietary polymethoxylated flavonoid found in Citrus fruits. Recent evidences show that NOB is a multifunctional pharmaceutical agent. The various pharmacological activities of NOB include neuroprotection, cardiovascular protection, antimetabolic disorder, anticancer, anti-inflammation, and antioxidation. These events may be underpinned by modulation of signaling cascades, including PKA/ERK/MEK/CREB, NF-κB, MAPK, Ca2+/CaMKII, PI3K/Akt1/2, HIF-1α, and TGFβ signaling pathways. The metabolites may exhibit stronger beneficial effects than NOB on diseases pathogenesis. The biological activities of NOB have been clarified on many systems. This review aims to discuss the pharmacological effects of NOB with specific mechanisms of actions. NOB may become a promising candidate for potential drug development. However, further investigations of NOB on specific intracellular targets and clinical trials are still needed, especially for in vivo medical applications.
Osteoarthritis (OA) constitutes a major health problem. Different signaling pathways are involved that impair homeostasis, but the cross-talk between them (although well investigated and partly understood), remains unclear. HIF-1α promotes chondrocyte differentiation and survival, while HIF-2α coactivates with β-catenin and NF-κB pathways to promote chondrocyte apoptosis and endochondral ossification. Depending on the ALK1/ALK5 ratio in chondrocytes, the TGFβ pathway can play an anabolic or catabolic role. TGFβ1 can activate the β-catenin signaling pathway via ALK5, Smad3, PI3K, and PKA pathways. The mediator Axins balance TGF-β and Wnt/β-catenin signaling during chondrocyte proliferation and maturation. However, the biological functions of Wnt/β-catenin signaling are still controversial. Both excessive and insufficient β-catenin levels may impair the homeostasis of articular chondrocytes by enhancing pathological maturation and apoptosis, respectively; loss- and gain-of-functions of β-catenin cause apoptosis at the center of the joint and chondrocyte maturation at the periphery, depending on the vascularity. The NF-κB transcription factor can be triggered by a host of stress-related stimuli including pro-inflammatory cytokines. The recent discovery of functional cross-regulation between these pathways has shown complex roles for HIF-1α/HIF-2α, TGFβ/BMP, Wnt/β-catenin, and NF-κB signaling pathways in the pathogenesis of OA. This has important implications for potential therapeutic agents directed at these pathways. This review attempts to cover the literature of the past three years dealing with the biology and pathology of the HIF-1α/-2α, TGFβ/BMP, Wnt/β-catenin, and NF-κB/cytokines signaling pathways in OA.
Osteoarthritis (OA) is a chronic degenerative joint disease characterized by articular cartilage destruction, synovial inflammation, and osteophyte formation. No effective treatments are available. The current pharmacological medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) and analgesics, accompanied by possible adverse effects, might ameliorate OA symptoms. But they do not arrest the progression of OA. Traditional Chinese medicine (TCM) provides medical value by modification of disease and symptoms in OA. Valuable work on exploring TCM merits for OA patients has been investigated using modern technologies, although the complicated interacting network among the numerous components indicates the uncertainty of target specification. This review will provide an overview of the action mechanism of TCM in the last 5 years, discussing the TCM activities of anti-inflammation, antiapoptosis, antioxidation, anticatabolism, and proliferation in OA. TCM is a proposed medical option for OA treatment.
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