FOXO4-DRI improves spermatogenesis in aged mice through reducing senescence-associated secretory phenotype secretion from Leydig cells.

Male ageing is always accompanied by decreased fertility. The forkhead O (FOXO) transcription factor FOXO4 is reported to be highly expressed in senescent cells. Upon activation, it binds p53 in the nucleus, preventing senescent cell apoptosis and maintaining senescent cells in situ. Leydig cells play key roles in assisting spermatogenesis. Leydig cell senescence leads to deterioration of the microenvironment of the testes and impairs spermatogenesis. In this study, we observed that FOXO4-DRI, a specific FOXO4- p53 binding blocker, induced apoptosis in senescent Leydig cells, reduced the secretion of certain Senescence-Associated Secretory Phenotype and improved the proliferation of cocultured GC-1 SPG cells. In naturally aged mice, FOXO4-DRI-treated aged mice exhibited increased sperm quality and improved spermatogenesis.

FOXO4-D-Retro-Inverso targets extracellular matrix production in fibroblasts and ameliorates bleomycin-induced pulmonary fibrosis in mice.

Pulmonary fibrosis (PF) occurs in various end stages of lung disease, and it is characterized by persistent scarring of the lung parenchyma with excessive deposition of extracellular matrix (ECM), leading to degressive quality of life and earlier mortality. FOXO4-D-Retro-Inverso (FOXO4-DRI), a synthesis peptide as a specific FOXO4 blocker, selectively induced dissociation of the FOXO4-p53 complex and nuclear exclusion of p53. Simultaneously, the p53 signaling pathway has been reported to activate in fibroblasts isolated from IPF fibrotic lung tissues and the p53 mutants cooperate with other factors that have the ability to disturb the synthesis of ECM. Yet, whether FOXO4-DRI influences the nuclear exclusion of p53 and then obstructs PF progress is still unknown. In this research, we explored the effect of FOXO4-DRI on bleomycin (BLM)-induced PF mouse model and activated fibroblasts model. The animal group of FOXO4-DRI therapeutic administration shows a milder pathologic change and less collagen deposition compared with the BLM-induced group. We also found the FOXO4-DRI resets the distribution of intranuclear p53 and concurrently decreased the total ECM proteins content. After further validation, FOXO4-DRI may well be a promising therapeutic approach to treating pulmonary fibrosis.

Targeting Multiple Homeostasis-Maintaining Systems by Ionophore Nigericin Is a Novel Approach for Senolysis.

Within the present study we proposed a novel approach for senolysis based on the simultaneous disturbance of the several homeostasis-maintaining systems in senescent cells including intracellular ionic balance, energy production and intracellular utilization of damaged products. Of note, we could not induce senolysis by applying ouabain, amiloride, valinomycin or NH4Cl-compounds that modify each of these systems solely. However, we found that ionophore nigericin can disturb plasma membrane potential, intracellular pH, mitochondrial membrane potential and autophagy at once. By affecting all of the tested homeostasis-maintaining systems, nigericin induced senolytic action towards stromal and epithelial senescent cells of different origins. Moreover, the senolytic effect of nigericin was independent of the senescence-inducing stimuli. We uncovered that K+ efflux caused by nigericin initiated pyroptosis in senescent cells. According to our data, the higher sensitivity of senescent cells compared to the control ones towards nigericin-induced death was partially mediated by the lower intracellular K+ content in senescent cells and by their predisposition towards pyroptosis. Finally, we proposed an interval dosing strategy to minimize the negative effects of nigericin on the control cells and to achieve maximal senolytic effect. Hence, our data suggest ionophore nigericin as a new senotherapeutic compound for testing against age-related diseases.

FOXO4 peptide targets myofibroblast ameliorates bleomycin-induced pulmonary fibrosis in mice through ECM-receptor interaction pathway.

Pulmonary fibrosis (PF) is a progressive interstitial lung disease with limited treatment options. The incidence and prevalence of PF is increasing with age, cell senescence has been proposed as a pathogenic driver, the clearance of senescent cells could improve lung function in PF. FOXO4-D-Retro-Inverso (FOXO4-DRI), a synthesis peptide, has been reported to selectively kill senescent cells in aged mice. However, it remains unknown if FOXO4-DRI could clear senescent cells in PF and reverse this disease. In this study, we explored the effect of FOXO4-DRI on bleomycin (BLM)-induced PF mouse model. We found that similar as the approved medication Pirfenidone, FOXO4-DRI decreased senescent cells, downregulated the expression of senescence-associated secretory phenotype (SASP) and attenuated BLM-induced morphological changes and collagen deposition. Furthermore, FOXO4-DRI could increase the percentage of type 2 alveolar epithelial cells (AEC2) and fibroblasts, and decrease the myofibroblasts in bleomycin (BLM)-induced PF mouse model. Compared with mouse and human lung fibroblast cell lines, FOXO4-DRI is inclined to kill TGF-ß-induced myofibroblast in vitro. The inhibited effect of FOXO4-DRI on myofibroblast lead to a downregulation of extracellular matrix (ECM) receptor interaction pathway in BLM-induced PF. Above all, FOXO4-DRI ameliorates BLM-induced PF in mouse and may be served as a viable therapeutic option for PF.

Senolytic Peptide FOXO4-DRI Selectively Removes Senescent Cells From in vitro Expanded Human Chondrocytes.

Autologous chondrocyte implantation (ACI) is a procedure used to treat articular cartilage injuries and prevent the onset of post-traumatic osteoarthritis. In vitro expansion of chondrocytes, a necessary step in ACI, results in the generation of senescent cells that adversely affect the quality and quantity of newly formed cartilage. Recently, a senolytic peptide, fork head box O transcription factor 4-D-Retro-Inverso (FOXO4-DRI), was reported to selectively kill the senescent fibroblasts. In this study, we hypothesized that FOXO4-DRI treatment could remove the senescent cells in the expanded chondrocytes, thus enhancing their potential in generating high-quality cartilage. To simulate the in vitro expansion for ACI, chondrocytes isolated from healthy donors were expanded to population doubling level (PDL) 9, representing chondrocytes ready for implantation. Cells at PDL3 were also used to serve as the minimally expanded control. Results showed that the treatment of FOXO4-DRI removed more than half of the cells in PDL9 but did not significantly affect the cell number of PDL3 chondrocytes. Compared to the untreated control, the senescence level in FOXO4-DRI treated PDL9 chondrocytes was significantly reduced. Based on the result from standard pellet culture, FOXO4-DRI pre-treatment did not enhance the chondrogenic potential of PDL9 chondrocytes. However, the cartilage tissue generated from FOXO4-DRI pretreated PDL9 cells displayed lower expression of senescence-relevant secretory factors than that from the untreated control group. Taken together, FOXO4-DRI is able to remove the senescent cells in PDL9 chondrocytes, but its utility in promoting cartilage formation from the in vitro expanded chondrocytes needs further investigation.

FOXO4-DRI alleviates age-related testosterone secretion insufficiency by targeting senescent Leydig cells in aged mice.

Male late-onset hypogonadism is an age-related disease, the core mechanism of which is dysfunction of senescent Leydig cells. Recent studies have shown that elimination of senescent cells can restore proper homeostasis to aging tissue. In the present study, we found that the fork head box O (FOXO) transcription factor FOXO4 was specially expressed in human Leydig cells and that its translocation to the nucleus in the elderly was related to decreased testosterone synthesis. Using hydrogen peroxide-induced senescent TM3 Leydig cells as an in vitro model, we observed that FOXO4 maintains the viability of senescent Leydig cells and suppresses their apoptosis. By disrupting the FOXO4-p53 interaction, FOXO4-DRI, a specific FOXO4 blocker, selectively induced p53 nuclear exclusion and apoptosis in senescent Leydig cells. In naturally aged mice, FOXO4-DRI improved the testicular microenvironment and alleviated age-related testosterone secretion insufficiency. These findings reveal the therapeutic potential of FOXO4-DRI for the treatment of male late-onset hypogonadism.

FOXO4 D-retro-inverso peptide increases radiosensitivity of non-small cell lung cancer cells / 中华放射医学与防护杂志

Objective To explore the effects of FOXO4 D-retro-inverso peptide (FOXO4-DRI)on the radiosensitivity of non-small cell lung cancer (NSCLC) cells.Methods To detect the effect of FOXO4-DRI on NSCLC cells,H460 and A549 human lung cancer cells were divided into four groups,including untreated control,FOXO4-DRI,γ-ray irradiation and FOXO4-DRI + γ-ray groups.A sigle dose rate of 0.99 Gy γ-rays was used for radiation.H460 cells were administered with 6 μmol/L FOXO4-DRI and A549 cells were adiminstered with 30 μmol/L FOXO4-DRI at 10 min before radiation.Cell viability and survival were detected by CCK-8 assay and colony formation assay,respectively.Cell migration was detected by wound healing assay.Apoptosis and cell cycle arrest were detected with flow cytometry.Results FOXO4-DRI inhibited growth of H460 and A549 cells (t =1.06-50.75,P＜ 0.05),and decreased cell mobility (t =33.37-139.10,P＜0.05) and colony formation (t =5.20-93.48,P＜0.05).FOXO4-DRI also increased apoptosis (t=2.95-42.00,P＜0.05) and caused a cell cycle arrest at G0/G1 phase accompanied with a decreased proportion of G2/M phase (t =3.50-3 1.59,P＜0.05).Furthermore,FOXO4-DRI increased radiosensitivity of both H460 cells and A549 cells (t =2.94-23.40,P＜0.05),caused a Further Decrease of radiation-mediated mobility (t =5.25,7.56,P＜0.05) and colony formation (t =8.43-34.00,P＜ 0.05) and a more increase of radiation-induced apoptosis (t =9.20-11.52,P ＜0.05).FOXO4-DRI also further decreased the proportion of G2/M phase cells but increased the proportion of S phase cells (t =3.85-17.62,P ＜ 0.05).Conclusion FOXO4-DRI increases radiosensitivity of NSCLC cells by inducing apoptosis and suppressing cell proliferation.

FOXO4 D-retro-inverso peptide increases radiosensitivity of non-small cell lung cancer cells / 中华放射医学与防护杂志

Objective@#To explore the effects of FOXO4 D-retro-inverso peptide (FOXO4-DRI) on the radiosensitivity of non-small cell lung cancer (NSCLC) cells.@*Methods@#To detect the effect of FOXO4-DRI on NSCLC cells, H460 and A549 human lung cancer cells were divided into four groups, including untreated control, FOXO4-DRI, γ-ray irradiation and FOXO4-DRI + γ-ray groups. A sigle dose rate of 0.99 Gy γ-rays was used for radiation. H460 cells were administered with 6 μmol/L FOXO4-DRI and A549 cells were adiminstered with 30 μmol/L FOXO4-DRI at 10 min before radiation. Cell viability and survival were detected by CCK-8 assay and colony formation assay, respectively. Cell migration was detected by wound healing assay. Apoptosis and cell cycle arrest were detected with flow cytometry.@*Results@#FOXO4-DRI inhibited growth of H460 and A549 cells (t=1.06-50.75, P<0.05), and decreased cell mobility (t=33.37-139.10, P<0.05) and colony formation (t=5.20-93.48, P<0.05). FOXO4-DRI also increased apoptosis (t=2.95-42.00, P<0.05) and caused a cell cycle arrest at G0/G1 phase accompanied with a decreased proportion of G2/M phase (t=3.50-31.59, P<0.05). Furthermore, FOXO4-DRI increased radiosensitivity of both H460 cells and A549 cells (t=2.94-23.40, P<0.05), caused a Further Decrease of radiation-mediated mobility (t=5.25, 7.56, P<0.05) and colony formation (t=8.43-34.00, P<0.05) and a more increase of radiation-induced apoptosis (t=9.20-11.52, P<0.05). FOXO4-DRI also further decreased the proportion of G2/M phase cells but increased the proportion of S phase cells (t=3.85-17.62, P<0.05).@*Conclusion@#FOXO4-DRI increases radiosensitivity of NSCLC cells by inducing apoptosis and suppressing cell proliferation.

Cellular senescence as a therapeutic target to improve renal transplantation outcome.

Kidney transplants from aged donors are more vulnerable to ischemic injury, suffer more from delayed graft function and have a lower graft survival compared to kidneys from younger donors. On a cellular level, aging results in an increase in cells that are in a permanent cell cycle arrest, termed senescence, which secrete a range of pro-inflammatory cytokines and growth factors. Consequently, these senescent cells negatively influence the local milieu by causing inflammaging, and by reducing the regenerative capacity of the kidney. Moreover, the oxidative damage that is inflicted by ischemia-reperfusion injury during transplantation can induce senescence and accelerate aging. In this review, we describe recent developments in the understanding of the biology of aging that have led to the development of a new class of therapeutic agents aimed at eliminating senescent cells. These compounds have already shown to be able to restore tissue homeostasis in old mice, improve kidney function and general health- and lifespan. Use of these anti-senescence compounds holds great promise to improve the quality of marginal donor kidneys as well as to remove senescent cells induced by ischemia-reperfusion injury. Altogether, senescent cell removal may increase the donor pool, relieving the growing organ shortage and improve long-term transplantation outcome.