With the global increase of the elderly population, the improvement of the treatment for various aging-related diseases and the extension of a healthy lifespan have become some of the most important current medical issues. In order to understand the developmental mechanisms of aging and aging-related disorders, animal models are essential to conduct relevant studies. Among them, mice have become one of the most prevalently used model animals for aging-related studies due to their high similarity to humans in terms of genetic background and physiological structure, as well as their short lifespan and ease of reproduction. This review will discuss some of the common and emerging mouse models of accelerated aging and related chronic diseases in recent years, with the aim of serving as a reference for future application in fundamental and translational research.

In human cells, telomeres are elongated by the telomerase complex that contains the reverse transcriptase hTERT and RNA template TERC/hTR. Poly(A)-specific ribonuclease (PARN) is known to trim hTR precursors by removing poly(A) tails. However, the precise mechanism of hTR 3′ maturation remains largely unknown. Target of Egr1 (TOE1) is an Asp-Glu-Asp-Asp (DEDD) domain containing deadenylase that is mutated in the human disease Pontocerebella Hypoplasia Type 7 (PCH7) and implicated in snRNA and hTR processing. We have previously found TOE1 to localize specifically in Cajal bodies, where telomerase RNP complex assembly takes place. In this study, we showed that TOE1 could interact with hTR and the telomerase complex. TOE1-deficient cells accumulated hTR precursors, including oligoadenylated and 3′-extended forms, which was accompanied by impaired telomerase activity and shortened telomeres. Telomerase activity in TOE1-deficient cells could be rescued by wild-type TOE1 but not the catalytically inactive mutant. Our results suggest that hTR 3′ end processing likely involves multiple exonucleases that work in parallel and/or sequentially, where TOE1 may function non-redundantly as a 3′-to-5′ exonuclease in conjunction with PARN. Our study highlights a mechanistic link between TOE1 mutation, improper hTR processing and telomere dysfunction in diseases such as PCH7.

Evidence supports prophylactic use of olanzapine for the treatment of chemotherapy-induced nausea and vomiting (CINV). However, most studies to date have focused on patients with single-day highly emetogenic chemotherapy (HEC). Currently, administration of antiemetic therapies for nausea and vomiting induced by multiday chemotherapy regimens remains a challenge. In this study, we evaluated the efficacy of olanzapine combined with triple antiemetic therapy for the prevention of CINV in patients receiving multiday chemotherapy. We performed a randomized, double-blind, placebo-controlled phase 3 trial in 22 hospitals. Eligible patients were between 18 and 75 years old, were diagnosed with malignant solid tumors, and they had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2. All the study participants were scheduled to be treated with chemotherapy regimens containing 3-day cisplatin (3-day total dose ≥75 mg/m²). Randomization was computer generated and stratified by gender and chemotherapy treatment history. Allocation was done via an interactive web response system. Enrolled patients were randomly assigned 1:1 to receive either 5 mg olanzapine or placebo orally before bedtime for 5 days combined with intravenous fosaprepitant (150 mg) 1 h before the administration of cisplatin on day 1, ondansetron hydrochloride intravenously, and dexamethasone orally 30 min before cisplatin from days 1 to 3. Dexamethasone was also administered at the same time on days 4 and 5. The primary endpoint was the proportion of subjects with complete response (no vomiting and no rescue therapy) within the overall phase (days 1-8) after starting chemotherapy. Baseline plasma concentrations of P-substance and 5-HT were measured for exploratory analysis. This study was registered at ClinicalTrials.gov, number NCT04536558. Between December 2020 and September 2021, 349 patients with malignant solid tumors were enrolled in the study, with 175 participants randomly assigned to receive olanzapine and 174 participants assigned to receive placebo. The proportion of patients who achieved a complete response in the overall phase was significantly higher in the olanzapine group than in the placebo group (69% vs. 58%, P = 0.031). A complete response benefit was observed in the olanzapine group versus the placebo group in almost all the subgroups. Four factors were considered significantly associated with complete response in multivariable analysis: treatment group, gender, baseline plasma concentration of 5-HT, and prior radiotherapy. All the reported adverse events associated with olanzapine administration were grades 1 and 2. Olanzapine (5 mg) combined with fosaprepitant, ondansetron, and dexamethasone was better than triple antiemetic therapy alone for patients receiving multiday chemotherapy regimens. Based on these results, the four-drug combination should be recommended as the best antiemetic regimen given to patients receiving multiday cisplatin-based chemotherapy and baseline plasma concentration of 5-HT may be used to identify individuals who are prone to CINV. However, all these findings need to be further validated in future studies. Jiangsu Hansoh Pharmaceutical Group Co., Ltd. provided research grant and study drugs for this investigator-initiated study.

Protection of telomere 1 (POT1), the telomeric single-stranded DNA (ssDNA)-binding protein in the shelterin complex, has been implicated in the DNA damage response, tumorigenesis and aging. Telomere dysfunction induced by telomere deprotection could accelerate cellular senescence in primary human cells. While previous work demonstrated the biological mechanism of POT1 in aging and cancer, how POT1 is posttranscriptionally regulated remains largely unknown. To better understand the POT1 regulatory axis, we performed bioinformatic prediction, and selected candidates were further confirmed by dual-luciferase reporter assay. Collectively, our results revealed that miR-185 can significantly reduce POT1 mRNA and protein levels by directly targeting the POT1 3’-untranslated region (3’-UTR). Overexpression of miR-185 increased telomere dysfunction-induced foci (TIF) signals in both cancer cells and primary human fibroblasts. Elevated miR-185 led to telomere elongation in the telomerase-positive cell line HTC75, which was phenotypically consistent with POT1 knocking down. Moreover, miR-185 accelerated the replicative senescence process in primary human fibroblasts in a POT1-dependent manner. Interestingly, increased serum miR-185 could represent a potential aging-related biomarker. Taken together, our findings reveal miR-185 as a novel aging-related miRNA that targets POT1 and provide insight into the telomere and senescence regulatory network at both the intracellular and extracellular levels.

Melioidosis is a severe disease caused by the Gram-negative bacterium Burkholderia pseudomallei. Previously we showed that pretreatment of mice with CpG oligodeoxynucleotide (CpG ODN) 2 to 10 days prior to B. pseudomallei challenge conferred as high as 90% protection, but this window of protection was rather short. In the present study, we therefore aimed to prolong this protective window and to gain further insight into the mechanisms underlying the protection induced by CpG ODN against B. pseudomallei infection. It was found that the CpG ODN incorporated with cationic liposomes (DOTAP) but not zwitterionic liposomes (DOPC) provided complete protection against bacterial challenge. Although marked elevation of gamma interferon (IFN-γ) was found in the infected animals 2 days postinfection, it was significantly lowered by the DOTAP-plus-CpG ODN pretreatment. When appropriately activated, the phagocytic index and oxidative burst responses of neutrophils appeared not to be elevated. However, macrophages from stimulated mice showed higher levels of nitric oxide production and exhibited higher levels of antimicrobial activities, judging from lower numbers of viable intracellular bacteria. Taken together, our results demonstrate that DOTAP can enhance the protective window period of CpG ODN to at least 30 days and provide 100% protection against B. pseudomallei infection. The protective effect of DOTAP plus CpG ODN could provide an alternative approach to preventing this lethal infection, for which no vaccine is yet available.

Reverse transcriptase hTERT is essential to telomerase function in stem cells, as well as in 85–90% of human cancers. Its high expression in stem cells or cancer cells has made telomerase/hTERT an attractive therapeutic target for anti-aging and anti-tumor applications. In this study, we screened a natural product library containing 800 compounds using an endogenous hTERT reporter. Eight candidates have been identified, in which sanguinarine chloride (SC) and brazilin (Braz) were selected due to their leading inhibition. SC could induce an acute and strong suppressive effect on the expression of hTERT and telomerase activity in multiple cancer cells, whereas Braz selectively inhibited telomerase in certain types of cancer cells. Remarkably, SC long-term treatment could cause telomere attrition and cell growth retardation, which lead to senescence features in cancer cells, such as the accumulation of senescence-associated β-galactosidase (SA-β-gal)-positive cells, the upregulation of p16/p21/p53 pathways and telomere dysfunction-induced foci (TIFs). Additionally, SC exhibited excellent capabilities of anti-tumorigenesis, both in vitro and in vivo. In the mechanism, the compound down-regulated several active transcription factors including p65, a subunit of NF-κB complex, and reintroducing p65 could alleviate its suppression of the hTERT/telomerase. Moreover, SC could directly bind hTERT and inhibit telomerase activity in vitro. In conclusion, we identified that SC not only down-regulates the hTERT gene’s expression, but also directly affects telomerase/hTERT. The dual function makes this compound an attractive drug candidate for anti-tumor therapy.