The complement system is a part of the immune system and consists of multiple complement components with biological functions such as defense against pathogens and immunomodulation. The complement system has three activation pathways: the classical pathway, the lectin pathway, and the alternative pathway. Increasing evidence indicates that the complement system plays a role in aging. Complement plays a role in inflammatory processes, metabolism, apoptosis, mitochondrial function, and Wnt signaling pathways. In addition, the complement system plays a significant role in aging-related diseases, including Alzheimer’s disease, age-related macular degeneration, and osteoarthritis. However, the effect of complement on aging and aging-related diseases is still unclear. Thus, a better understanding of the potential relationship between complement, aging, and aging-related diseases will provide molecular targets for treating aging, while focusing on the balance of complement in during treatment. Inhibition of a single component does not result in a good outcome. In this review, we discussed the research progress and effects of complement in aging and aging-related diseases.

Treating Idiopathic pulmonary fibrosis (IPF) remains challenging owing to its relentless progression, grim prognosis, and the scarcity of effective treatment options. Emerging evidence strongly supports the critical role of accelerated senescence in alveolar epithelial cells (AECs) in driving the progression of IPF. Consequently, targeting senescent AECs emerges as a promising therapeutic strategy for IPF. Curcumin analogue EF24 is a derivative of curcumin and shows heightened bioactivity encompassing anti-inflammatory, anti-tumor and anti-aging properties. The objective of this study was to elucidate the therapeutic potential and underlying molecular mechanisms of EF24 in the treatment of IPF. A549 and ATII cells were induced to become senescent using bleomycin. Senescence markers were examined using different methods including senescence-associated β-galactosidase (SA-β-gal) staining, western blotting, and q-PCR. Mice were intratracheally administrated with bleomycin to induce pulmonary fibrosis. This was validated by micro-computed tomography (CT), masson trichrome staining, and transmission electron microscope (TEM). The role and underlying mechanisms of EF24 in IPF were determined in vitro and in vivo by evaluating the expressions of PTEN, AKT/mTOR/NF-κB signaling pathway, and mitophagy using western blotting or flow cytometry. We identified that the curcumin analogue EF24 was the most promising candidate among 12 compounds against IPF. EF24 treatment significantly reduced senescence biomarkers in bleomycin-induced senescent AECs, including SA-β-Gal, PAI-1, P21, and the senescence-associated secretory phenotype (SASP). EF24 also effectively inhibited fibroblast activation which was induced by senescent AECs or TGF-β. We revealed that PTEN activation was integral for EF24 to inhibit AECs senescence by suppressing the AKT/mTOR/NF-κB signaling pathway. Additionally, EF24 improved mitochondrial dysfunction through induction of mitophagy. Furthermore, EF24 administration significantly reduced the senescent phenotype induced by bleomycin in the lung tissues of mice. Notably, EF24 mitigates fibrosis and promotes overall health benefits in both the acute and chronic phases of IPF, suggesting its therapeutic potential in IPF treatment. These findings collectively highlight EF24 as a new and effective therapeutic agent against IPF by inhibiting senescence in AECs.

Accumulating evidence indicates that the increased burden of senescent cells (SCs) in aged organisms plays an important role in many age-associated diseases. The pharmacological elimination of SCs with “senolytics” has been emerging as a new therapy for age-related diseases and extending the healthy lifespan. In the present study, we identified that cycloastragenol (CAG), a secondary metabolite isolated from Astragalus membrananceus, delays age-related symptoms in mice through its senolytic activity against SCs. By screening a series of compounds, we found that CAG selectively kills SCs by inducing SCs apoptosis and that this process is associated with the inhibition of Bcl-2 antiapoptotic family proteins and the PI3K/AKT/mTOR pathway. In addition, CAG treatment also suppressed the development of the senescence-associated secretory phenotype (SASP) in SCs, thereby inhibiting cell migration mediated by the SASP. Furthermore, the administration of CAG for 2 weeks to mice with irradiation-induced aging alleviated the burden of SCs and improved the animals’ age-related physical dysfunction. Overall, our studies demonstrate that CAG is a novel senolytic agent with in vivo activity that has the potential to be used in the treatment of age-related diseases.

Melanoma is a malignant skin tumor that originates from melanocytes. The pathogenesis of melanoma involves a complex interaction that occurs between environmental factors, ultraviolet (UV)-light damage, and genetic alterations. UV light is the primary driver of the skin aging process and development of melanoma, which can induce reactive oxygen species (ROS) production and the presence of DNA damage in the cells, and results in cell senescence. As cellular senescence plays an important role in the relationship that exists between the skin aging process and the development of melanoma, the present study provides insight into the literature concerning the topic at present and discusses the relationship between skin aging and melanoma, including the mechanisms of cellular senescence that drive melanoma progression, the microenvironment in relation to skin aging and melanoma factors, and the therapeutics concerning melanoma. This review focuses on defining the role of cellular senescence in the process of melanoma carcinogenesis and discusses the targeting of senescent cells through therapeutic approaches, highlighting the areas that require more extensive research in the field.

YWHAG is a subtype of the 14-3-3 protein family that regulates the transduction of multiple signaling pathways in cells, such as the phosphoinositide 3-kinase–protein kinase B (PI3K-AKT) and mitogen-activated protein kinase (MAPK) pathways, by recognizing and binding to specific phosphorylated target protein motifs. These signaling pathways are widely found to be abnormally activated or shut down in human diseases, such as cancer and neurodegenerative diseases. Different evidence has shown that the expression levels and functions of YWHAG in different tumors are not the same. Meanwhile, the potential functions of YWHAG in these diseases and its role in regulating abnormal signaling pathways are still unknown. Therefore, further exploration and research are needed to determine YWHAG’s core role in regulating signaling pathways and whether YWHAG can be a therapeutic target for diseases to develop corresponding drugs. This review will revisit the structure and function of YWHAG, elaborate on the newly identified YWHAG-interacting proteins in recent years, summarize the functions of YWHAG in cancer while comparing it with the homologous family member YWHAZ, explore the functions of YWHAG in neurodegenerative diseases, and present our perspectives on drug-screening strategies targeting YWHAG.

Pathological accumulation of senescent cells (SnCs) across tissues drives aging and age-related diseases. Senolytic agents targeting senescent cell anti-apoptotic pathways (SCAPs) hold promise for treating age-related diseases, yet their efficacy is limited by the heterogeneity of SnC survival mechanisms beyond canonical BCL-2 family pathways. Here, we identify intracellular complement C3 (intC3) as a previously unrecognized determinant of senolytic responsiveness. C3 was consistently and markedly upregulated across diverse senescent cell types and aged tissues; however, its depletion via knockout (KO) or knockdown (KD) did not alter canonical senescence phenotypes. Unexpectedly, C3 KD attenuated ABT263- and bortezomib-mediated SnC apoptosis, while sustaining pro-survival AKT/S6K signaling. In aged C3-knockout (C3KO) mice, ABT263 failed to effectively eliminate SnCs, resulting in persistent senescence markers, unresolved senescence-associated secretory phenotype (SASP), and exacerbated fibrosis. Mechanistically, AKT inhibition rescued senolytic sensitivity in C3-KD SnCs, confirming AKT/S6K as the functional downstream mediator. These findings redefine intC3 as an intracellular stress sensor that sensitizes SnCs to apoptotic clearance—transcending its canonical extracellular immune role—and position the intC3–AKT axis as a potential target for overcoming senolytic resistance.