Pten deletion in the hematopoietic stem cells (HSC) causes a myeloproliferative disorder, which may subsequently develop into a T-cell acute lymphoblastic leukemia (T-ALL). β-catenin expression was dramatically increased in the c-KitmidCD3+Lin- leukemia stem cells (LSC) and was critical for T-ALL development. Therefore, the inactivation of β-catenin in LSC may have a potential to eliminate the LSC. In this study, we investigated the mechanism of enhancement of the β-catenin expression and subsequently used a drug to inactivate β-catenin expression in T-ALL. Western blot (WB) analysis revealed an increased level of β-catenin in the leukemic cells, but not in the pre-leukemic cells. Furthermore, the WB analysis of the thymic cells from different stages of leukemia development showed that increased expression of β-catenin was not via the pS9-GSK3β signaling, but was dependent on the pT308-Akt activation. Miltefosine (Hexadecylphosphocholine) is the first oral anti-Leishmania drug, which is a phospholipid agent and has been shown to inhibit the PI3K/Akt activity. Treatment of the PtenΔ/Δ leukemic mice with Miltefosine for different durations demonstrated that the pT308-Akt and the β-catenin expressions were inhibited in the leukemia blast cells. Miltefosine treatment also suppressed the TGFβ1/Smad3 signaling pathway. Analysis of TGFβ1 in the sorted subpopulations of the blast cells showed that TGFβ1 was secreted by the CD3+CD4- subpopulation and may exert effects on the subpopulations of both CD3+CD4+ and CD3+CD4- leukemia blast cells. When a TGFβR1 inhibitor, SB431542 was injected into the PtenΔ/Δ leukemic mice, the Smad3 and β-catenin expressions were down-regulated. On the basis of the results, we conclude that Miltefosine can suppress leukemia by degrading β-catenin through repression of the pT308-Akt and TGFβ1/Smad3 signaling pathways. This study demonstrates a possibility to inhibit Pten loss-associated leukemia genesis via targeting Akt and Smad3.
We have recently shown that age-dependent regional brain atrophy and lateral ventricle expansion may be linked with impaired cognitive and locomotor functions. However, metabolic profile transformation in different brain regions during aging is unknown. This study examined metabolic changes in the hippocampus, medial prefrontal cortex (mPFC) and striatum of middle- and late-aged Sprague-Dawley rats using ultrahigh performance liquid chromatography coupled with high-resolution accurate mass-orbitrap tandem mass spectrometry. Thirty-eight potential metabolites were altered in hippocampus, 29 in mPFC, and 14 in striatum. These alterations indicated that regional metabolic mechanisms in lated-aged rats are related to multiple pathways including glutathione, sphingolipid, tyrosine, and purine metabolism. Thus, our findings might be useful for understanding the complexity of metabolic mechanisms in aging and provide insight for aging and health span.
Gonadotrophin-releasing hormone (GnRH) expression is associated with the two-pore domain potassium ion (K+) channel-related K+ (TREK) channel trek2a expression and melatonin levels. We aimed to investigate correlation of trek2a expression with gnrh3 expression, and regulatory mechanisms of trek2a expression by the melatonin receptor Mt1 and α2-adrenoceptor which are regulated by melatonin. trek2a specific siRNA, Mt1 antagonist luzindole and α2-adrenoceptor antagonist prazosin were administered into the adult zebrafish brain and gene expressions were examined by real-time PCR. trek2a specific siRNA administration significantly reduced expression levels of trek2a, gnrh3 and mt1. Luzindole administration suppressed trek2a and gnrh3 expressions. Prazosin administration reduced trek2a and gnrh3 expressions. It is suggested that Trek2a regulates gnrh3 expression under the control of Mt1 and α2-adrenoceptor.
The human gut microbiota comprises of trillions of micro-organisms in the gut some which secrete metabolites that play a pivotal role in supporting optimal body and organ functions. These dynamic and malleable gut microbes share a bidirectional relationship with their hosts that supports health in an age- and sex-dependent manner. Disruption of the gut microbiota or decrease in their diversity and richness due to unhealthy changes in lifestyle, diet or social disconnection, always results in unwanted outcomes on the host health which fuel chronic disease symptoms including neurodegenerative diseases. Thus, impairment of gut microbiota composition, results in organ decline that accelerates an individual's biological ageing. Here we review evidence supporting the bidirectional relationships between the gut microbiota and biological ageing.
Vitellogenin (Vtg) serves as the precursor of yolk protein and exhibits widespread distribution in tissues, including in the ovary of both vertebrates and invertebrates. Vtg plays a critical role in facilitating oocyte maturation and embryonic development following oviposition. In this study, we have successfully elucidated the complete transcript sequence of TtVtg6-like from an ancient chelicerate Tachypleus tridentatus. The TtVtg6-like transcript encompassed a length of 4887 bp and encoded 1629 amino acids residues. Notably, TtVtg6-like was found to contain 25 exons. Furthermore, the molecular weight and isoelectric point of TtVtg6-like were determined to be 191.6 KDa and 6.73, respectively. Subsequent mRNA expression analysis demonstrated the specific expression of TtVtg6-like in ovary and yellow connective tissue. In addition, TtVtg6-like was located and distributed in both ovary and yellow connective tissue. Intriguingly, employing an siRNA approach to silence TtVtg6-like resulted in a decrease in TtVtg6-like transcription levels. Concomitantly, TtVtg6-like silencing led to increase production of ROS, ultimately resulting in DNA damage and cell apoptosis within the ovarian primary cell. The induction of apoptosis ovarian primary cells due to TtVtg6-like silencing was further corroborated through TUNEL assay and flow cytometry analysis. Overall, our findings underscore the significance of TtVtg6-like in ovarian cell development, revealing its potential association with ovarian cell apoptosis. Consequently, the insights gained from this study contribute to the future exploration of vitellogenesis and ovarian development in T. tridentatus.
The saliva of the medicinal leech contains various anticoagulants. Some of them, such as hirudin, are well known. However, it is reasonable to believe that not all anticoagulant proteins from medicinal leech saliva have been identified. We previously performed a comprehensive study of the transcriptome, genome, and proteome of leech salivary gland cells, which led to the discovery of several previously unknown hypothetical proteins that may have anticoagulant properties. Subsequently, we obtained a series of recombinant proteins and investigated their impact on coagulation in in vitro assays. We identified a previously undescribed protein that exhibited a high ability to suppress coagulation. The His-tagged recombinant protein was expressed in Escherichia coli and purified using metal chelate chromatography. To determine its activity, commonly used coagulation methods were used: activated partial thromboplastin time, prothrombin time, and thrombin inhibition clotting assay. Clotting and chromogenic assays for factor Xa inhibition were performed to evaluate anti-Xa activity. We used recombinant hirudin as a control anticoagulant protein in all experiments. The new protein showed significantly greater inhibition of coagulation than hirudin at the same molar concentrations in the activated partial thrombin time assay. However, hirudin demonstrated better results in the direct thrombin inhibition test, although the tested protein also exhibited the ability to inhibit thrombin. The chromogenic analysis of factor Xa inhibition revealed no activity, whereas the clotting test for factor Xa showed the opposite result. Thus, a new powerful anticoagulant protein has been discovered in the medicinal leech. This protein is homologous to antistatin, with 28 % identical amino acid residues. The recombinant protein was expressed in E. coli. This protein is capable of directly inhibiting thrombin, and based on indirect evidence, other proteases of the blood coagulation cascade have been identified.
Thioredoxin interacting protein (TXNIP) has emerged as a significant regulator of β-cell mass and loss, rendering it an attractive target for treating diabetes. We previously showed that Shiga-Y6, a fluorinated curcumin derivative, inhibited TXNIP mRNA and protein expression in vitro, raising the question of whether the same effect could be translated in vivo. Herein, we examined the effect of Shiga-Y6 on TNXIP levels and explored its therapeutic potential in a mouse model of diabetes, Akita mice. We intraperitoneally injected Shiga-Y6 (SY6; 30 mg/kg of body weight) or vehicle into 8-week-old Akita mice for 28 consecutive days. On day 29, the mice were euthanized, following which the serum levels of glucose, insulin, and glucagon were measured using ELISA, the expression of TXNIP in pancreatic tissue lysates was determined using western blotting, and the level of β-cell apoptosis was assessed using the TUNEL assay. TXNIP levels in the pancreatic tissue of Akita mice were significantly elevated compared with wild-type (WT) mice. Shiga-Y6 administration for 28 days significantly lowered those levels compared with Akita mice that received vehicle to a level comparable to WT mice. In immunohistochemical analysis, both α- to β-cell ratio and the number of apoptotic β-cells were significantly reduced in SY6-treated Akita mice, compared with vehicle-treated Akita mice. Findings from the present study suggest a potential of Shiga-Y6 as an antidiabetic agent through lowering TXNIP protein levels and ameliorating pancreatic β-cells apoptosis.
The increasing prevalence of lean diabetes has prompted the generation of animal models that mimic metabolic disease in humans. This study aimed to determine the optimum streptozotocin-nicotinamide (STZ-NA) dosage ratio to elicit lean diabetic features in a rat model. It also used a proton nuclear magnetic resonance (1H NMR) urinary metabolomics approach to identify the metabolic effect of metformin treatment on this novel rat model. Three different STZ-NA dosage regimens (by body weight: Group A: 110 mg/kg NA and 45 mg/kg STZ; Group B: 180 mg/kg NA and 65 mg/kg STZ and Group C: 120 mg/kg NA and 60 mg/kg STZ) were administered to Sprague-Dawley rats along with oral metformin. Group A diabetic rats (A-DC) showed favorable serum biochemical analyses and a more positive response toward oral metformin administration relative to the other STZ-NA dosage ratio groups. Orthogonal partial least squares-discriminant analysis (OPLS-DA) revealed that glucose, citrate, pyruvate, hippurate, and methylnicotinamide differentiating the OPLS-DA of A-MTF rats (Group A diabetic rats treated with metformin) and A-DC model rats. Subsequent metabolic pathway analyses revealed that metformin treatment was associated with improvement in dysfunctions caused by STZ-NA induction, including carbohydrate metabolism, cofactor metabolism, and vitamin and amino acid metabolism. In conclusion, our results identify the best STZ-NA dosage ratio for a rat model to exhibit lean type 2 diabetic features with optimum sensitivity to metformin treatment. The data presented here could be informative to improve our understanding of non-obese diabetes in humans through the identification of possible activated metabolic pathways in the STZ-NA-induced diabetic rats model.