Fluorinated curcumin derivative (Shiga-Y6) modulates the level of thioredoxin-interacting protein (TXNIP) in a mouse model of diabetes.

Thioredoxin interacting protein (TXNIP) has emerged as a significant regulator of ß-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 ß-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 ß-cell ratio and the number of apoptotic ß-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 ß-cells apoptosis.

Metabolomics Profiling of Age-Associated Metabolites in Malay Population.

Aging is a complex process characterized by progressive loss of functional abilities due to the accumulation of molecular damages. Metabolomics could offer novel insights into the predictors and mechanisms of aging. This cross-sectional study is aimed at identifying age-associated plasma metabolome in a Malay population. A total of 146 (90 females) healthy participants aged 28-69 were selected for the study. Untargeted metabolomics profiling was performed using liquid chromatography-tandem mass spectrometry. Association analysis was based on the general linear model. Gender-associated metabolites were adjusted for age, while age-associated metabolites were adjusted for gender or analyzed in a gender-stratified manner. Gender-associated metabolites such as 4-hydroxyphenyllactic acid, carnitine, cortisol, and testosterone sulfate showed higher levels in males than females. Deoxycholic acid and hippuric acid were among the metabolites with a positive association with age after being adjusted for gender, while 9(E),11(E)-conjugated linoleic acid, cortisol, and nicotinamide were negatively associated with age. In gender-stratified analysis, glutamine was one of the common metabolites that showed a direct association with age in both genders, while metabolites such as 11-deoxy prostaglandin F2ß, guanosine monophosphate, and testosterone sulfate were inversely associated with age in males and females. This study reveals several age-associated metabolites in Malays that could reflect the changes in metabolisms during aging and may be used to discern the risk of geriatric syndromes and disorders later. Further studies are required to determine the interplay between these metabolites and environmental factors on the functional outcomes during aging.

Optimization of 3D Immunofluorescence Analysis and Visualization Using IMARIS and MeshLab.

The precision of colocalization analysis is enhanced by 3D and is potentially more accurate than 2D. Even though 3D improves the visualization of colocalization analysis, rendering a colocalization model may generate a model with numerous polygons. We developed a 3D colocalization model of FtMt/LC3 followed by simplification. Double immunofluorescence staining of FtMt and LC3 was conducted, and stacked images were acquired. We used IMARIS to render the 3D colocalization model of FtMt/LC3 and further processed it with MeshLab to decimate and generate a less complex colocalization model. We examined the available simplification algorithm using MeshLab in detail and evaluated the feasibility of each procedure in generating a model with less complexity. The quality of the simplified model was subsequently assessed. MeshLab's available shaders were scrutinized to facilitate the spatial colocalization determination. Finally, we showed that QECD was the most effective method for reducing the polygonal complexity of the colocalization model without compromising its quality. In addition, we would recommend implementing the x-ray shader, which we found useful for visualizing colocalization. As 3D was found to be more accurate in quantifying colocalization, our study provides a novel and dependable method for rendering 3D models for colocalization analysis.

Pharmaceutical Potential of Casein-Derived Tripeptide Met-Lys-Pro: Improvement in Cognitive Impairments and Suppression of Inflammation in APP/PS1 Mice.

BACKGROUND: Tripeptide Met-Lys-Pro (MKP), a component of casein hydrolysates, has effective angiotensin-converting enzyme (ACE) inhibitory activity. Brain angiotensin II enzyme activates the NADPH oxidase complex via angiotensin II receptor type 1 (AT1) and enhances oxidative stress injury. ACE inhibitors improved cognitive function in Alzheimer's disease (AD) mouse models and previous clinical trials. Thus, although undetermined, MKP may be effective against pathological amyloid-ß (Aß) accumulation-induced cognitive impairment. OBJECTIVE: The current study aimed to investigate the potential of MKP as a pharmaceutical against AD by examining MKP's effect on cognitive function and molecular changes in the brain using double transgenic (APP/PS1) mice. METHODS: Experimental procedures were conducted in APP/PS1 mice (n = 38) with a C57BL/6 background. A novel object recognition test was used to evaluate recognition memory. ELISA was used to measure insoluble Aß40, Aß42, and TNF-α levels in brain tissue. Immunohistochemical analysis allowed the assessment of glial cell activation in MKP-treated APP/PS1 mice. RESULTS: The novel object recognition test revealed that MKP-treated APP/PS1 mice showed significant improvement in recognition memory. ELISA of brain tissue showed that MKP significantly reduced insoluble Aß40, Aß42, and TNF-α levels. Immunohistochemical analysis indicated the suppression of the marker for microglia and reactive astrocytes in MKP-treated APP/PS1 mice. CONCLUSION: Based on these results, we consider that MKP could ameliorate pathological Aß accumulation-induced cognitive impairment in APP/PS1 mice. Furthermore, our findings suggest that MKP potentially contributes to preventing cognitive decline in AD.

LC3/FtMt Colocalization Patterns Reveal the Progression of FtMt Accumulation in Nigral Neurons of Patients with Progressive Supranuclear Palsy.

Mitochondrial ferritin (FtMt) is a mitochondrial iron storage protein associated with neurodegenerative diseases. In patients with progressive supranuclear palsy (PSP), FtMt was shown to accumulate in nigral neurons. Here, we investigated FtMt and LC3 in the post-mortem midbrain of PSP patients to reveal novel aspects of the pathology. Immunohistochemistry was used to assess the distribution and abnormal changes in FtMt and LC3 immunoreactivities. Colocalization analysis using double immunofluorescence was performed, and subcellular patterns were examined using 3D imaging and modeling. In the substantia nigra pars compacta (SNc), strong FtMt-IR and LC3-IR were observed in the neurons of PSP patients. In other midbrain regions, such as the superior colliculus, the FtMt-IR and LC3-IR remained unchanged. In the SNc, nigral neurons were categorized into four patterns based on subcellular LC3/FtMt immunofluorescence intensities, degree of colocalization, and subcellular overlapping. This categorization suggested that concomitant accumulation of LC3/FtMt is related to mitophagy processes. Using the LC3-IR to stage neuronal damage, we retraced LC3/FtMt patterns and revealed the progression of FtMt accumulation in nigral neurons. Informed by these findings, we proposed a hypothesis to explain the function of FtMt during PSP progression.

A Fluorine-19 Magnetic Resonance Probe, Shiga-Y5, Downregulates Thioredoxin-Interacting Protein Expression in the Brain of a Mouse Model of Alzheimer's Disease.

Thioredoxin-interacting protein (TXNIP) is involved in multiple disease-associated functions related to oxidative stress, especially by inhibiting the anti-oxidant- and thiol-reducing activity of thioredoxin (TXN). Shiga-Y5 (SY5), a fluorine-19 magnetic resonance probe for detecting amyloid-ß deposition in the brain, previously showed therapeutic effects in a mouse model of Alzheimer's disease; however, the mechanism of action of SY5 remains unclear. SY5 passes the blood-brain barrier and then undergoes hydrolysis to produce a derivative, Shiga-Y6 (SY6), which is a TXNIP-negative regulator. Therefore, this study investigates the therapeutic role of SY5 as the prodrug of SY6 in the thioredoxin system in the brain of a mouse model of Alzheimer's disease. The intraperitoneal injection of SY5 significantly inhibited TXNIP mRNA (p = 0.0072) and protein expression (p = 0.0143) induced in the brain of APP/PS1 mice. In contrast, the levels of TXN mRNA (p = 0.0285) and protein (p = 0.0039) in the brain of APP/PS1 mice were increased after the injection of SY5. The ratio of TXN to TXNIP, which was decreased (p = 0.0131) in the brain of APP/PS1 mice, was significantly increased (p = 0.0072) after the injection of SY5. These results suggest that SY5 acts as a prodrug of SY6 in targeting the thioredoxin system and could be a potential therapeutic compound in oxidative stress-related diseases in the brain.

Gene Expression Profile in Different Age Groups and Its Association with Cognitive Function in Healthy Malay Adults in Malaysia.

The mechanism of cognitive aging at the molecular level is complex and not well understood. Growing evidence suggests that cognitive differences might also be caused by ethnicity. Thus, this study aims to determine the gene expression changes associated with age-related cognitive decline among Malay adults in Malaysia. A cross-sectional study was conducted on 160 healthy Malay subjects, aged between 28 and 79, and recruited around Selangor and Klang Valley, Malaysia. Gene expression analysis was performed using a HumanHT-12v4.0 Expression BeadChip microarray kit. The top 20 differentially expressed genes at p < 0.05 and fold change (FC) = 1.2 showed that PAFAH1B3, HIST1H1E, KCNA3, TM7SF2, RGS1, and TGFBRAP1 were regulated with increased age. The gene set analysis suggests that the Malay adult's susceptibility to developing age-related cognitive decline might be due to the changes in gene expression patterns associated with inflammation, signal transduction, and metabolic pathway in the genetic network. It may, perhaps, have important implications for finding a biomarker for cognitive decline and offer molecular targets to achieve successful aging, mainly in the Malay population in Malaysia.

Immunohistochemical Study of Mitochondrial Ferritin in the Midbrain of Patients with Progressive Supranuclear Palsy.

Mitochondrial ferritin (FtMt) is a novel ferritin that is localized in the mitochondria. FtMt expression is low in the liver and spleen, and high in the heart, testis, and brain. We previously detected FtMt in dopaminergic neurons in the substantia nigra pars compacta (SNc) in human and monkey midbrains. We investigated the localization and expression of FtMt in the midbrain of patients with progressive supranuclear palsy (PSP) and controls using a monoclonal antibody (C65-2) against human FtMt. FtMt immunoreactivity was weakly detected in neuromelanin-containing neurons in the SNc and ventral tegmental area (VTA) of control cases compared with PSP, which exhibited a remarkable increase in FtMt immunoreactivity. Preincubation of C65-2 with the immunizing FtMt peptide significantly reduced the staining, indicating the specificity of C65-2. Several puncta were observed outside the neurons of PSP, in contrast with the control cases. Double immunofluorescence histochemistry for FtMt and tyrosine hydroxylase (TH), glial fibrillary acidic protein, and Iba1 showed localization of FtMt in dopaminergic neurons, microglia, and astrocytes in PSP. Furthermore, FtMt immunoreactivity was detected in a few TH-negative neurons. In the SNc and VTA, FtMt immunoreactivity colocalized with phosphorylated tau immunoreactivity. Our results indicate that FtMt is involved in the pathology of PSP. Clarifying the involvement of FtMt in PSP is of great interest.

Effect of Age on the Protein Profile of Healthy Malay Adults and its Association with Cognitive Function Competency.

BACKGROUND: Many studies on biochemical and psychological variables have aimed to elucidate the association between aging and cognitive function. Demographic differences and protein expression have been reported to play a role in determining the cognitive capability of a population. OBJECTIVE: This study aimed to determine the effect of age on the protein profile of Malay individuals and its association with cognitive competency. METHODS: A total of 160 individuals were recruited and grouped accordingly. Cognitive competency of each subject was assessed with several neuropsychological tests. Plasma samples were collected and analyzed with Q Exactive HF Orbitrap. Proteins were identified and quantitated with MaxQuant and further analyzed with Perseus to determine differentially expressed proteins. PANTHER, Reactome, and STRING were applied for bioinformatics output. RESULTS: Our data showed that the Malay individuals are vulnerable to the deterioration of cognitive function with aging, and most of the proteins were differentially expressed in concordance. Several physiological components and pathways were shown to be involved, giving a hint of a promising interpretation on the induction of aging toward the state of the Malays' cognitive function. Nevertheless, some proteins have shown a considerable interaction with the generated protein network, which provides a direction of focus for further investigation. CONCLUSION: This study demonstrated notable changes in the expression of several proteins as age increased. These changes provide a promising platform for understanding the biochemical factors affecting cognitive function in the Malay population. The exhibited network of protein-protein interaction suggests the possibility of implementing regulatory intervention in ameliorating Malay cognitive function.

DNA damage and protein oxidation associated with ageing correlate with cognitive dysfunction in a Malaysian population.

Ageing is associated with increased oxidative stress accompanied by cognitive decline. The aim of this study was to evaluate oxidative stress biomarkers and their possible relationship with cognitive performances during ageing among the Malay population. Approximately 160 healthy Malay adults aged between 28 and 79 years were recruited around Selangor and Klang Valley. Cognitive function was assessed by Montreal Cognitive Assessment (MoCA), forward digit span (FDS), backward digit span (BDS), digit symbol, Rey Auditory Verbal Learning Test immediate recalled [RAVLT(I)] and delayed recalled [RAVLT(D)], and visual reproduction immediate recalled (VR-I) and delayed recalled (VR-II). DNA damage, plasma protein carbonyl and malondialdehyde (MDA) levels were also determined. Cognitive function test showed significant lower scores of MoCA, BDS, RAVLT(I), RAVLT(D), digit symbol, VR-I, and VR-II in the older age group (60 years old) compared with the 30-, 40-, and 50-year-old group. The extent of DNA damage was sequential with age: 60 > 50 > 40 > 30, whereas protein carbonyl was higher in 40-, 50-, and 60-year-old groups compared with the youngest group (30 years old). However, the MDA level was observed unchanged in all age groups. Approximately 21.88% of the participants had cognitive impairment. Multiple logistic regression analysis revealed that DNA damage and protein carbonyl levels are predictors for cognitive impairment in healthy Malays. In conclusion, cognitive decline occurred in healthy adult Malay population at an early age of 30 years old with corresponding higher DNA damage and protein oxidation.