Morphine treatment is associated with diminished telomere length together with down-regulated TERT and TERF2 mRNA levels

Nesfatin-1 attenuated lipopolysaccharide-induced inflammatory response and senescence in human dental pulp cells

Lipopolysaccharide (LPS)-triggered damage in human dental pulp cells (hDPCs) is associated with the progression of gingivitis, which is inflammation of the gingival tissue. Nesfatin-1 is a peptide secreted by neurons and peripheral tissues. Here, we report a novel property of Nesfatin-1 in ameliorating LPS-induced inflammatory response and senescence in hDPCs. First, we demonstrate that Nesfatin-1 repressed LPS-triggered expression of inflammatory factors. Secondly, Nesfatin-1 restored telomerase activity and the expression of human telomerase reverse transcriptase (hTERT) and telomeric repeat binding factor 2 (TERF2) against LPS. Senescence-associated β-galactosidase (SA-β-gal) staining assay revealed that Nesfatin-1 attenuated LPS-induced cellular senescence in hDPCs. We also found that Nesfatin-1 increased telomerase activity in LPS-challenged hDPCs. It is also shown that Nesfatin-1 reduced the expression of plasminogen activator inhibitor-1 (PAI-1) and p16. Additionally, LPS stimulation reduced the expression of SIRT1, which was rescued by Nesfatin-1. However, the silencing of sirtuin1 (SIRT1) abrogated the protective property of Nesfatin-1 in preventing cellular senescence, implying that the function of Nesfatin-1 is regulated by SIRT1. Taken together, our findings suggest that Nesfatin-1 might possess a protective effect against gingivitis.

Neratinib stimulates senescence of mammary cancer cells by reducing the levels of SIRT1

Neratinib, a typical small-molecule, pan-human tyrosine kinase inhibitor (TKI), has been licensed for the treatment of human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, the underlying pharmacological mechanism is still unknown. In the current study, we report a novel function of Neratinib by showing that its treatment stimulates senescence of the mammary cancer AU565 cells. Our results demonstrate that Neratinib induces mitochondrial injury by increasing mitochondrial reactive oxygen species (ROS) and reducing intracellular adenosine triphosphate (ATP). Also, we found that Neratinib induced DNA damage by increasing the levels of 8-Hydroxy-desoxyguanosine (8-OHdG) and γH2AX in AU565 cells. Additionally, Neratinib reduced the levels of telomerase activity after 7 and 14 days incubation. Importantly, the senescence-associated-β-galactosidase (SA-β-Gal) assay revealed that Neratinib stimulated senescence of AU565 cells. Neratinib decreased the gene levels of human telomerase reverse transcriptase (hTERT) but increased those of telomeric repeat-binding factor 2 (TERF2) in AU565 cells. Further study displayed that Neratinib upregulated the expression of K382 acetylation of p53 (ac-K382) and p21 but reduced the levels of sirtuin-1 (SIRT1). However, overexpression of SIRT1 abolished the effects of Neratinib in cellular senescence. These findings provide strong preclinical evidence of Neratinib's treatment of breast cancer.

The protective effects of Chromofungin in oligomeric amyloid β42 (Aβ42)-induced toxicity in neurons in Alzheimer's disease

Oligomeric Aβ42 is considered to play a harmful role in the pathophysiology of Alzheimer's disease (AD). Prolonged exposure to oligomeric Aβ42 could induce neuronal damage including cellular senescence. Amelioration of Aβ42-induced cellular senescence has been considered as a promising strategy for the treatment of AD. Chromofungin, a chromogranin A-derived peptide, has displayed various biological functions in different types of cells and tissues. However, the effects of Chromofungin on oligomeric Aβ42-induced cellular senescence have not been previously reported. In the current study, we report a novel function of Chromofungin by showing that treatment with Chromofungin could ameliorate Aβ42-induced neurotoxicity in M17 neuronal cells. The Cell Counting Kit-8 (CCK-8) assay and the lactate dehydrogenase (LDH) release experiments revealed that 0.5 and 1 mM are the optimal concentrations of Chromofungin for cell culture in M17 cells. Challenging with oligomeric Aβ42 (5 μM) for 7 and 14 days led to a significant decrease in telomerase activity, which was rescued by Chromofungin dose-dependently. Additionally, the senescence-associated β-galactosidase (SA-β-gal) staining assay demonstrated that Chromofungin mitigated oligomeric Aβ42-induced cellular senescence. Correspondingly, treatment with Chromofungin reversed the gene expression of human telomerase reverse transcriptase (hTERT), telomeric repeat-binding factor 2 (TERF2), and p21 against oligomeric Aβ42 in M17 neurons. Interestingly, Chromofungin attenuated oligomeric Aβ42-induced oxidative stress (OS) in M17 cells by reducing the production of intracellular reactive oxygen species (ROS) but increasing the levels of intracellular superoxide dismutase (SOD). Importantly, the presence of Chromofungin reduced the expression of cyclooxygenase2 (COX-2) as well as the generation of prostaglandin E2 (PGE2). Transduction with Ad-COX-2 impaired the effects of Chromofungin on telomerase activity and the profile of cellular senescence. Our findings suggest that Chromofungin might act as a potential agent for the treatment of AD.

Pazopanib stimulates senescence of renal carcinoma cells through targeting nuclear factor E2-related factor 2 (Nrf2)

Renal cell carcinoma (RCC) is the most common kidney cancer with high mortality rate. Pazopanib has been approved for the treatment of RCC. However, the underlying mechanism is not clear. Here, we report a novel finding by showing that treatment with Pazopanib could promote cellular senescence of the human RCC cell line ACHN. Cells were stimulated with 5, 10, and 20 μM Pazopanib, respectively. Cellular senescence was measured using senescence-associated β-galactosidase (SA-β-Gal) staining. Western blot analysis and real-time polymerase chain reaction were used to measure the mRNA and protein expression of nuclear factor E2-related factor 2 (Nrf2), γH2AX, human telomerase reverse transcriptase (hTERT), telomeric repeat binding factor 2 (TERF2), p53 and plasminogen activator inhibitor (PAI). First, we found that exposure to Pazopanib reduced the cell viability of ACHN cells. Additionally, Pazopanib induced oxidative stress  by increasing the production of reactive oxygen species, reducing the levels of glutathione peroxidase, and promoting nuclear translocation of Nrf2. Interestingly, Pazopanib exposure resulted in DNA damage by increasing the expression of γH2AX. Importantly, Pazopanib increased cellular senescence and reduced telomerase activity. Pazopanib also reduced the gene expression of hTERT but increased the gene expression of TERF2. Correspondingly, we found that Pazopanib increased the expression of p53 and PAI at both the mRNA and protein levels. To elucidate the underlying mechanism, the expression of Nrf2 was knocked down by transduction with Ad- Nrf2 shRNA. Results indicate that silencing of Nrf2 in ACHN cells abolished the effects of Pazopanib in stimulating cellular senescence and reducing telomerase activity. Consistently, knockdown of Nrf2 restored the expression of p53 and PAI in ACHN cells. Based on these results, we explored a novel mechanism whereby which Pazopanib displays a cytotoxicity effect in RCC cells through promoting cellular senescence mediated by Nrf2.

A pilot study examining the relationship between chronic heroin use and telomere length among individuals of African ancestry

BACKGROUND

Prior research has suggested a possible link between heroin use and shortened telomere length (TL), a marker of cellular aging and genomic stability. We sought to replicate these findings by examining the relationship between TL and heroin use among individuals of African ancestry.

METHODS

This cross-sectional study examined TL among 57 participants [17.5 % female; mean age 48.0 (±6.80) years] of African ancestry with Opioid Use Disorder (OUD) and a mean heroin use duration of 18.2 (±10.7) years. Quantitative polymerase chain reaction (qPCR) was used to calculate TL as the ratio between telomere repeat copy number (T) and a single-copy gene, copy number (S). The primary dependent variable was TL (T/S Ratio) measured in kilobase pairs. Covariates included heroin use years and personality traits. Using a hybrid approach, multiple linear regression and Bayesian linear regression examined the association of chronological age, heroin use years and personality traits with TL.

RESULTS

The multiple linear regression model fit the data well, R2 = 0.265, F(7,49) = 2.53, p < .026. Chronological age (β = -0.36, p = .017), neuroticism (β = 0.46, p = .044), and conscientiousness (β = 0.52, p = .040) were significant predictors of TL. Bayesian linear regression provided moderate support for the alternate hypothesis that chronological age and TL are associated, BF10 = 5.77, R2 = 0.120. The posterior summary of the coefficient was M = 0.719 (SD = 0.278, 95 % credible interval [-1.28, -0.163]).

CONCLUSIONS

Contrary to prior studies, these findings suggest that heroin use duration may not be significantly associated with TL among individuals of African ancestry, highlighting the need for more rigorous research to elucidate the complexity of this relationship.

Midazolam alleviates cellular senescence in SH-SY5Y neuronal cells in Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) impacts the daily life of aging people. Oligomerized amyloid β (Aβ)-associated neuronal senescence is involved in the pathological mechanism of AD. Blockage of neuronal senescence has been considered an important strategy for the treatment of AD. Midazolam is a hypnotic-sedative drug with pleiotropic properties.

AIMS

However, the effects of Midazolam in oligomerized Aβ_1.42 -induced neurotoxicity have not been reported previously. Here, we investigate whether Midazolam possesses a beneficial effect against oligomerized Aβ_1.42 in SH-SY5Y neuronal cells.

MATERIALS AND METHODS

Cellular senescence was assessed using senescence-associated β-galactosidase staining. Telomerase activity was measured using the TeloTAGGG Telomerase PCR ELISA.

RESULTS

First, the lactate dehydrogenase release assay demonstrates that 10 and 20 µM are the optimal concentrations of Midazolam used for cell cultures. Senescence-associated β-galactosidase staining results indicate that exposure to oligomerized Aβ_1.42 significantly increased cellular senescence of SH-SY5Y cells, but it was significantly alleviated by Midazolam. Additionally, Midazolam restored the oligomerized Aβ_1.42 -induced reduction of telomerase activity. Interestingly, we found that oligomerized Aβ_1.42 remarkably reduced human telomerase reverse transcriptase (hTERT) gene expression but increased the telomeric repeat-binding factor 2 (TERF2) expression. However, treatment with Midazolam reversed the effects of oligomerized Aβ_1.42 on the hTERT and TERF2 gene expressions. Importantly, the presence of Midazolam attenuated Aβ_1.42 -induced p53 and p21 expressions. Mechanistically, Midazolam repressed the level of cyclooxygenase-2 (COX-2) and the release of prostaglandin E2. Importantly, overexpression of COX-2 abolished the impact of Midazolam against oligomerized Aβ_1.42 in neuronal senescence.

CONCLUSION

We conclude that the usage of Midazolam is a potential treatment strategy for AD.

Morphine may have a role in telomere shortening

Morphine/heroin may increase oxidative stress in drug-dependent persons. The imbalance between oxidative stress and antioxidant defense mechanisms can accelerate the shortening of telomere length. This article reports two sets of data; comparison of relative telomere length between heroin-dependent patients and healthy control group, as well as, investigation of the effect of morphine on the relative telomere length of human SH-SY5Y cells treated by morphine. Study participants were composed of 163 heroin-dependent patients and 166 unrelated healthy controls. SH-SY5Y cells were treated with (5 μM) morphine hydrochloride and incubated for 40 and 60 days. The relative telomere length was calculated as the T/S (telomere/single-copy gene) ratio using 36B4 as a reference for each sample, using quantitative real-time PCR. The mean (± SE) value of relative telomere length was 4.81 ± 0.21 and 6.38 ± 0.23 in leukocytes of heroin-dependent and control groups, respectively. The telomere length was significantly decreased in heroin-dependent participants (t = 4.97; df = 327; P < 0.0001). The relative telomere length in cells treated with morphine for 60 days was 4.50 ± 0.14 and in untreated cells was 5.75 ± 0.08. The difference was highly significant (t  =  7.68; df = 4; P = 0.002). Our present findings indicate that morphine and dependency on heroin are significantly associated with shorter telomeres. The present findings may help to explain some of the adverse effects of drug dependency on health such as accelerating biologic processes related to aging.

Phoenixin-14 Ameliorates Cellular Senescence Against Morphine in M17 Neuronal Cells

Drug dependence on morphine is commonly accompanied by neurodegenerative disorders. A previous study showed that prolonged exposure to morphine induces cellular senescence in neuronal cells by reducing telomere length. Phoenixin-14 is a newly discovered brain peptide with pleiotropic roles. However, it is unknown whether phoenixin-14 possesses a beneficial property against morphine-induced cellular senescence. Our results show that morphine reduced the expression of G protein-coupled receptor 173 (GPR173) in M17 neuronal cells. Therefore, we speculated that phoenixin-14, as a ligand for GPR173, may be involved in the morphine-mediated response in M17 cells. Further, we found that phoenixin-14 mitigated morphine-induced oxidative stress by reducing the reactive oxygen species (ROS) production and increasing superoxide dismutase (SOD) activity in M17 neuronal cells. The morphine-induced cellular senescence in M17 neuronal cells was prevented by phoenixin-14. Phoenixin-14 resolved the morphine-caused cell cycle arrest with significant changes in the expression levels of p21, cyclin-dependent kinases 6 (CDK6), and p-Rb. It also elevated the telomerase activity and restored the expressions of human telomerase reverse transcriptase (hTERT) and TERF2 in morphine-induced M17 neuronal cells. Furthermore, phoenixin-14 restored the yes-associated protein (YAP) expression against morphine in M17 neuronal cells. Knockdown of YAP abolished the beneficial effects of phoenixin-14 on cellular senescence against morphine induction. Taken together, these aggregate data demonstrate that phoenixin-14 prevented cellular senescence against morphine induction in M17 neuronal cells via regulating YAP expression.