APP Levels Research Articles

Novel melatonin-trientine conjugate as potential therapeutic agents for Alzheimer’s disease

Researchers continue to explore drug targets to treat the characteristic pathologies of Alzheimer's disease (AD). Some drugs relieve the pathological processes of AD to some extent, but the failed clinical trials indicate that multifunctional agents seem more likely to achieve the therapy goals for this neurodegenerative disease. Herein, a novel compound named melatonin-trientine (TM) has been covalently synthesized with the natural antioxidant compounds melatonin and the metal ion chelator trientine. After toxicological and pharmacokinetic verification, we elucidated the effects of intraperitoneal administration of TM on AD-like pathology in 6-month-old mice that express both the β-amyloid (Aβ) precursor protein and presenilin-1 (APP/PS1). We found that TM significantly decreased Aβ deposition and neuronal degeneration in the brains of the APP/PS1 double transgenic mice. This result may be due to the upregulation of iron regulatory protein-2 (IRP2), insulin degrading enzyme (IDE), and low density lipoprotein receptor related protein 1 (LRP1), which leads to decreases in APP and Aβ levels. Additionally, TM may promote APP non-amyloidogenic processing by activating the melatonin receptor-2 (MT2)-dependent signaling pathways, but not MT1. In addition, TM plays an important role in blocking γ-secretase, tau hyperphosphorylation, neuroinflammation, oxidative stress, and metal ion dyshomeostasis. Our results suggest that TM may effectively maximize the therapeutic efficacy of targeting multiple mechanisms associated with AD pathology.

Astrocyte calcium dysfunction causes early network hyperactivity in Alzheimer's disease.

SummaryDysfunctions of network activity and functional connectivity (FC) represent early events in Alzheimer’s disease (AD), but the underlying mechanisms remain unclear. Astrocytes regulate local neuronal activity in the healthy brain, but their involvement in early network hyperactivity in AD is unknown. We show increased FC in the human cingulate cortex several years before amyloid deposition. We find the same early cingulate FC disruption and neuronal hyperactivity in AppNL-F mice. Crucially, these network disruptions are accompanied by decreased astrocyte calcium signaling. Recovery of astrocytic calcium activity normalizes neuronal hyperactivity and FC, as well as seizure susceptibility and day/night behavioral disruptions. In conclusion, we show that astrocytes mediate initial features of AD and drive clinically relevant phenotypes.

Genetic inhibition of PDK1 robustly reduces plaque deposition and ameliorates gliosis in the 5×FAD mouse model of Alzheimer's disease.

Abundant recent evidence has shown that 3-phosphoinositide-dependent protein kinase 1 (PDK1) is activated in Alzheimer's disease (AD). However, it remains unknown whether inhibition of PDK1 in neurons may affect AD-like pathology in animal models of AD. Here, we aim to examine the effects of specific inactivation of neuronal PDK1 on pathology and behaviour in 5×FAD mice and to identify the underlying molecular mechanisms. The Cre-loxP system was employed to generate Pdk1 cKO/5×FAD mice, in which PDK1 is inactivated in excitatory neurons in the adult forebrain. Cellular and behavioural techniques were used to examine plaque burden, inflammatory responses and spatial working memory in mice. Biochemical and molecular analyses were conducted to investigate relevant mechanisms. First, Aβ deposition was massively decreased and gliosis was highly attenuated in Pdk1 cKO/5×FAD mice compared with 5×FAD mice. Second, memory deficits were significantly improved in Pdk1 cKO/5×FAD mice. Third, APP levels were notably decreased in Pdk1 cKO/5×FAD mice. Fourth, mammalian target of rapamycin (mTOR) signalling and ribosome biogenesis were reduced in Pdk1 cKO/5×FAD mice. Neuron-specific deletion of PDK1 robustly ameliorates AD-like pathology and improves spatial working memory in 5×FAD mice. We propose that genetic approach to inhibit PDK1 may be an effective strategy to slow AD.

Age-Dependent Behavioral and Metabolic Assessment of App NL-G-F/NL-G-F Knock-in (KI) Mice.

Mitochondria play a crucial role in Alzheimer's disease (AD) onset and progression. Traditional transgenic AD mouse models which were widely used in the past decades share a common limitation: The overexpression of APP and overproduction of amyloid-beta (Aβ) are accompanied by other APP peptide fragments, which could introduce artificial and non-clinically relevant phenotypes. Here, we performed an in-depth and time-resolved behavioral and metabolic characterization of a clinically relevant AD mouse model engineered to express normal physiological levels of APP harboring humanized Swedish (K670N/M671L), Beyreuther/Iberian (I716F), and Arctic (E693G) mutations (AppNL−G−F/NL−G−F), termed APP knock-in (APPKI) mice. Our result showed that APPKI mice exhibited fear learning deficits at 6-m age and contextual memory deficit at 12-m age. Histopathological analysis revealed mild amyloidosis (6E10) accompanied by microgliosis (Iba1) as early as 3 months, which progressed significantly together with significant astrocytosis at 6 and 12 m. We further analyzed hippocampal mitochondrial dysfunction by multiple assays, while 3-m APPKI mice brain mitochondrial function remains a similar level as WT mice. Significant mitochondrial dysfunction characterized by decreased ATP production and higher membrane potential with subsequent overproduction of reactive oxygen species (ROS) was observed in mitochondria isolated from 7-m APPKI mice hippocampal tissue. Morphologically, these mitochondria were larger in volume with a decreased level of mitochondrial fusion protein mitofusin-2 (MFN2). At 12 months, APPKI mice exhibit a significantly decreased total mitochondrial oxygen consumption rate (OCR) in isolated hippocampal mitochondria detected by high-resolution respirometry. These data indicate early mitochondrial dysfunction in the brain at pre-symptomatic age in the AppNL−G−F/NL−G−mice, which may play a key role in the progression of the disease. Moreover, the identified behavioral and bioenergetic alterations in this clinically relevant AD mouse model provide a valuable tool to optimize the temporal component for therapeutic interventions to treat AD.

Inhibition of PLK2 activity affects APP and tau pathology and improves synaptic content in a sex-dependent manner in a 3xTg mouse model of Alzheimer's disease

Converging lines of evidence suggest that abnormal accumulation of the kinase Polo-like kinase 2 (PLK2) might play a role in the pathogenesis of Alzheimer's disease (AD), possibly through its role in regulating the amyloid β (Aβ) cascade. In the present study, we investigated the effect of inhibiting PLK2 kinase activity in in vitro and in vivo models of AD neuropathology. First, we confirmed that PLK2 overexpression modulated APP and Tau protein levels and phosphorylation in cell culture, in a kinase activity dependent manner. Furthermore, a transient treatment of triple transgenic mouse model of AD (3xTg-AD) with a potent and specific PLK2 pharmacological inhibitor (PLK2i #37) reduced some neuropathological aspects in a sex-dependent manner. In 3xTg-AD males, treatment with PLK2i #37 led to lower Tau burden, higher synaptic protein content, and prevented learning and memory deficits. In contrast, treated females showed an exacerbation of Tau pathology, associated with a reduction in amyloid plaque accumulation. Overall, our findings suggest that PLK2 inhibition alters key components of AD neuropathology in a sex-dependent manner and might display a therapeutic potential for the treatment for AD and related dementia.

A novel multi-target strategy for Alzheimer's disease treatment via sublingual route: Donepezil/memantine/curcumin-loaded nanofibers.

Drug delivery systems that not only show efficacy through multiple therapeutic pathways but also facilitate patient drug use and exhibit a high bioavailability profile represent a promising strategy in the treatment of Alzheimer's disease (AD). Here, donepezil (DO)/memantine (MM)/curcumin (CUR)-loaded electrospun nanofibers (NFs) were produced for the treatment of AD. DSC, XRD, and FT-IR studies demonstrated the complete incorporation of the drug into PVA/PVP NFs. The disintegration profile was improved by loading the drugs in PVA/PVP with fast wetting (less than 1s), the start of disintegration (21s), and dispersion in 110s. The desired properties for sublingual application were achieved with the dissolution of NFs in 240s. The cell viability in DO/MM/CUR-loaded NFs was similar to the control group after 48h in the cell culture. DO/MM/CUR-loaded NFs enhanced the expressions of BDNF (13.5-fold), TUBB3 (8.9-fold), Neurog2 (5.6-fold), NeuroD1 (5.8-fold), Nestin (166-fold), and GFAP (115-fold). DO/MM/CUR-loaded NFs and powder of these drugs contained in these fibers were daily administered sublingually to intracerebroventricular-streptozotocin (icv-STZ) treated rats. DO/MM/CUR-loaded NFs treatment improved the short-term memory damage and enhanced memory, learning ability, and spatial exploration talent. Results indicated that the levels of Aβ, Tau protein, APP, GSK-3β, AChE, and TNF-α were significantly decreased, and BDNF was increased by DO/MM/CUR-loaded NFs treatment compared to the AD group. In the histopathological analysis of the hippocampus and cortex, neuritic plaques and neurofibrillary nodes were not observed in the rats treated with DO/MM/CUR-loaded NFs. Taken together, the sublingual route delivery of DO/MM/CUR-loaded NFs supports potential clinical applications for AD.

(-)-Epicatechin Provides Neuroprotection in Sodium Iodate-Induced Retinal Degeneration.

Oxidative stress, mitochondrial impairment, and pathological amyloid beta (Aβ) deposition are involved in the pathogenesis of dry age-related macular degeneration (AMD). The natural flavonoid (–)-epicatechin (EC) is known to be an antioxidant and neuroprotective compound. Whether EC plays a therapeutic role in AMD is unknown. In this work, we aimed to assess the efficacy and molecular mechanisms of EC against sodium iodate (NaIO3)-induced retinal degeneration in C57BL/6 mice via bioinformatic, morphological, and functional methods. We demonstrated that EC had no toxic effects on the retina and could ameliorate retinal deformation and thinning. EC treatment prevented outer retinal degeneration, reduced drusen-like deposits, increased b-wave amplitude in electroretinography, blocked retinal gliosis, and increased the number and quality of mitochondria. Importantly, EC increased the protein expression of OPA1 and decreased the expression of PINK1, indicating the role of EC in mitochondrial fusion that impaired by NaIO3. Moreover, EC downregulated APP and TMEM97 levels, upregulated PGRMC1 levels, and reduced subretinal Aβ accumulation. This study illustrated that EC, which may become a promising therapeutic strategy for AMD, prevented NaIO3-induced retinal degeneration, and this improvement may be associated with the mitochondrial quality control and the TMEM97/PGRMC1/Aβ signaling pathway.

Mobile Application Use and Loneliness among Older Adults in the Digital Age: Insights from a Survey in Hong Kong during the COVID-19 Pandemic.

Existing literature on the associations between use of mobile applications (i.e., mobile apps) and loneliness among older adults (OAs) has been mainly conducted before the outbreak of the COVID-19 pandemic. Since mobile apps have been increasingly used by OAs during the pandemic, subsequent effects on social and emotional loneliness need updated investigation. This paper examines the relationship between mobile app use and loneliness among Hong Kong’s OAs during the pandemic. In our research, 364 OAs with current use experience of mobile apps were interviewed through a questionnaire survey conducted during July and August 2021, which assessed the use frequency and duration of 14 mobile app types and levels of emotional and social loneliness. The survey illustrated communication (e.g., WhatsApp) and information apps were the most commonly used. Emotional loneliness was associated with the use of video entertainment (frequency and duration), instant communication (duration), and information apps (duration). Association between video entertainment apps’ use and emotional loneliness was stronger among older and less educated OAs. Our findings highlight the distinctive relationships between different types of apps and loneliness among Hong Kong’s OAs during the pandemic, which warrant further exploration via research into post-pandemic patterns and comparative studies in other regions.

Chronic vitamin D3 supplementation alleviates cognition impairment via inhibition of oxidative stress regulated by PI3K/AKT/Nrf2 in APP/PS1 transgenic mice

Oxidative stress plays essential role in the pathogenesis of Alzheimer's disease, and vitamin D3 (VD3) is a nutrient with neuroprotective and antioxidant activities. The present study aimed to confirm the neuroprotective effect and the ameliorative effect of cortical oxidative stress of VD3 in APP/PS1 transgenic mice. APP/PS1 mice were treated with VD3 for 20 weeks. After treatment, Morris Water Maze test was used to evaluate cognitive level. Western blotting was used to determine APP, p-tau, tau and PI3K/AKT/Nrf2 pathway-related protein expression levels. Immunohistochemical staining was performed to determine the levels of β amyloid peptide (Aβ) deposition. Enzyme linked immunosorbent assay was used to determine the 25(OH)D3 levels and oxidative stress status. Our results showed that treatment with VD3 ameliorated behavioral deficits of APP/PS1 mice. In addition, the administration of VD3 significantly increased the cortical 25(OH)D3 levels, while reducing the levels of cortical Aβ deposition and decreasing the expression levels of cortical APP, tau and p-tau in APP/PS1 mice. Moreover, VD3 protected the cortex against oxidative stress by enhancing the levels of superoxide dismutase, glutathione and total antioxidant capacity, and downregulating the malondialdehyde levels. Furthermore, VD3 clearly activated the PI3K/AKT/Nrf2 pathway, thereby elevating the expression levels of HO1 and NQO1. We concluded that VD3 improved cognitive function and cortical Alzheimer-like pathology of APP/PS1 mice, which may be related to the inhibition of oxidative stress via activation the PI3K/AKT/Nrf2 pathway.

Safety, Tolerability, and Immunogenicity of the ACI-24 Vaccine in Adults With Down Syndrome

Individuals with Down syndrome (DS) are at high risk of developing Alzheimer disease due to an increased dose of the amyloid precursor protein gene, APP, which leads to increased levels of full-length APP and its products, including amyloid-β (Aβ). The liposome-based antiamyloid ACI-24 vaccine is intended to treat neurological disorders caused by misfolded Aβ pathological protein. However, the safety, tolerability, and immunogenicity of the ACI-24 vaccine among adults with DS have not been fully examined. To assess the safety and tolerability of the ACI-24 vaccine among adults with DS as well as its ability to induce immunogenicity measured by anti-Aβ immunoglobulin G titers. This multicenter double-blind placebo-controlled dose-escalation phase 1b randomized clinical trial was conducted at 3 US academic medical centers with affiliated Down syndrome clinics between March 30, 2016, and June 29, 2020. A total of 20 adults with DS were screened; of those, 16 adults were eligible to participate. Eligibility criteria included men or women aged 25 to 45 years with cytogenetic diagnosis of either trisomy 21 or complete unbalanced translocation of chromosome 21. Between April 27, 2016, and July 2, 2018, participants were randomized 3:1 into 2 dose-level cohorts (8 participants per cohort, with 6 participants receiving the ACI-24 vaccine and 2 receiving placebo) in a 96-week study. Participants received 48 weeks of treatment followed by an additional 48 weeks of safety follow-up. Participants were randomized to receive 7 subcutaneous injections of ACI-24, 300 μg or 1000 μg, or placebo. Primary outcomes were measures of safety and tolerability as well as antibody titers. Among 16 enrolled participants, the mean (SD) age was 32.6 (4.4) years; 9 participants were women, and 7 were men. All participants were White, and 1 participant had Hispanic or Latino ethnicity. Treatment adherence was 100%. There were no cases of meningoencephalitis, death, or other serious adverse events (AEs) and no withdrawals as a result of AEs. Most treatment-emergent AEs were of mild intensity (110 of 132 events [83.3%]) and unrelated or unlikely to be related to the ACI-24 vaccine (113 of 132 events [85.6%]). No amyloid-related imaging abnormalities with edema or cerebral microhemorrhage and no evidence of central nervous system inflammation were observed on magnetic resonance imaging scans. Increases in anti-Aβ immunoglobulin G titers were observed in 4 of 12 participants (33.3%) receiving ACI-24 (2 receiving 300 μg and 2 receiving 1000 μg) compared with 0 participants receiving placebo. In addition, a greater increase was observed in plasma Aβ1-40 and Aβ1-42 levels among individuals receiving ACI-24. In this study, the ACI-24 vaccine was safe and well tolerated in adults with DS. Evidence of immunogenicity along with pharmacodynamic and target engagement were observed, and anti-Aβ antibody titers were not associated with any adverse findings. These results support progression to clinical trials using an optimized formulation of the ACI-24 vaccine among individuals with DS. ClinicalTrials.gov Identifier: NCT02738450.

Quantitative proteomic analysis of cerebrospinal fluid reveals CD163, A2M and full-length APP as potential diagnostic biomarkers of paediatric bacterial meningitis.

BackgroundBacterial meningitis (BM) is a life-threatening infectious disease of the central nervous system in infants and children. To date, no diagnostic methods for the early and precise diagnosis of paediatric BM have been developed.MethodsA label-free cerebrospinal fluid (CSF) quantitative proteomic analysis of 8 patients with confirmed or suspected BM, 9 patients with confirmed or suspected viral meningitis (VM) and 6 non-CNS-infected hospital patients was performed via high-resolution LC–MS/MS.ResultsOur CSF proteomic analysis allowed the identification of critical differences between the BM and non-BM groups. Compared to the proteomes of the non-BM groups, the proteome of the paediatric BM group was characterized by upregulation of complement and coagulation cascades, regulation of IGF transport, uptake by IGF-binding proteins and acute inflammatory response, downregulation of developmental growth, and metabolism of carbohydrates. Moreover, the levels of CD163, A2M and full-length APP in CSF showed excellent diagnostic performance for paediatric BM, with AUC values of 0.911 (95% CI: 0.839–0.984), 0.908 (95% CI: 0.816–1.000) and 0.944 (95% CI: 0.86, 1.000), respectively. Among them, A2M and full-length APP are reported here for the first time as potential diagnostic biomarkers of BM. The findings imply that peptidase regulator activity plays an important role in BM and provide potential novel targets for precision medicine in paediatric BM.ConclusionsCD163, A2M and full-length APP are validated as potential diagnostic biomarkers of paediatric BM.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12953-022-00191-5.

Age‐dependent behavioral and neuropathological assessment of analysis of AppNL‐G‐F/NL‐G‐Fknock‐in (KI) mice

Mitochondria play a crucial role in Alzheimer's disease (AD) onset and progression. Traditional transgenic AD mouse models share the limitation that the proteolytic processing of overexpressed mutant APP results in overproduction of amyloid‐beta (Aß) and other APP peptide fragments resulting in artificial, non‐clinically relevant phenotypes. Here we performed an in‐depth and time‐resolved behavioral and metabolic characterization of a clinically relevant AD mouse model engineered to express normal physiological levels of APP harboring humanized Swedish (K670N/M671L), Beyreuther/Iberian (I716F), and Arctic (E693G) mutations, (AppNL‐G‐F/NL‐G‐F), termed APP knock‐in (APPKI) mice. At 7 months of age, APPKI mice exhibited only learning deficit confirmed by both the water maze test and fear conditioning test. At the same age, we also observed mitochondrial dysfunction consisting of decreased ATP production, higher membrane potential with subsequent greater production of reactive oxygen species (ROS). Furthermore, mitochondria were larger in volume, accompanied by lower molecular markers of mitochondrial dynamics, mitofusin‐2 (Mfn2), at 6‐8 m. In contrast, the oxygen consumption rate (OCR) from 6 m APPKI hippocampal homogenates was similar to that of WT mice. At 12 months of age, APPKI mice exhibited learning and memory deficit, together with significantly decreased mitochondrial oxygen consumption rate detected by high‐resolution respirometry. Histopathology revealed minor amyloidosis accompanied by microgliosis (Iba1) as early as 3 months, which became more apparent at 6 and 12 m. These data indicate a wide range of brain mitochondrial dysfunction and associated cognitive deficits in APPKImice. Moreover, the identified behavioral and bioenergetic alterations in this physiologically relevant AD transgenic mouse model provide a valuable tool to optimize the temporal component for therapeutic interventions to treat AD.

Neuroprotective Effects of Green Tea Seed Isolated Saponin Due to the Amelioration of Tauopathy and Alleviation of Neuroinflammation: A Therapeutic Approach to Alzheimer's Disease.

Tauopathy is one of the major causes of neurodegenerative disorders and diseases such as Alzheimer’s disease (AD). Hyperphosphorylation of tau proteins by various kinases leads to the formation of PHF and NFT and eventually results in tauopathy and AD; similarly, neuroinflammation also exaggerates and accelerates neuropathy and neurodegeneration. Natural products with anti-tauopathy and anti-neuroinflammatory effects are highly recommended as safe and feasible ways of preventing and /or treating neurodegenerative diseases, including AD. In the present study, we isolated theasaponin E1 from ethanol extract of green tea seed and evaluated its therapeutic inhibitory effects on tau hyper-phosphorylation and neuroinflammation in neuroblastoma (SHY-5Y) and glioblastoma (HTB2) cells, respectively, to elucidate the mechanism of the inhibitory effects. The expression of tau-generating and phosphorylation-promoting genes under the effects of theasaponin E1 were determined and assessed by RT- PCR, ELISA, and western blotting. It was found that theasaponin E1 reduced hyperphosphorylation of tau and Aβ concentrations significantly, and dose-dependently, by suppressing the expression of GSK3 β, CDK5, CAMII, MAPK, EPOE4(E4), and PICALM, and enhanced the expression of PP1, PP2A, and TREM2. According to the ELISA and western blotting results, the levels of APP, Aβ, and p-tau were reduced by treatment with theasaponin E1. Moreover, theasaponin E1 reduced inflammation by suppressing the Nf-kB pathway and dose-dependently reducing the levels of inflammatory cytokines such as IL-1beta, IL-6, and TNF-alpha etc.

Transcript levels in plasma contribute substantial predictive value as potential Alzheimer's disease biomarkers in African Americans.

SummaryBackgroundAfrican Americans (AA) remain underrepresented in Alzheimer's disease (AD) research, despite the prevalence of AD being double in AA compared to non-Hispanic whites. To address this disparity, our group has established the Florida Consortium for African American Alzheimer's Disease Studies (FCA3DS), focusing on the identification of genetic risk factors and novel plasma biomarkers.MethodUtilizing FCA3DS whole exome sequence (WES) and plasma RNA samples from AD cases (n=151) and cognitively unimpaired (CU) elderly controls (n=269), we have performed differential gene expression (DGE) and expression quantitative trait locus (eQTL) analyses on 50 transcripts measured with a custom nanoString® panel. We designed this panel to measure, in plasma, cell-free mRNA (cf-mRNA) levels of AD-relevant genes.FindingsAssociation with higher plasma CLU in CU vs. AD remained significant after Bonferroni correction. Study-wide significant eQTL associations were observed with 105 WES variants in cis with 22 genes, including variants in genes previously associated with AD risk in AA such as ABCA7 and AKAP9. Results from this plasma eQTL analysis identified AD-risk variants in ABCA7 and AKAP9 that are significantly associated with lower and higher plasma mRNA levels of these genes, respectively. Receiver operating characteristic analysis of age, sex APOE-ε4 dosage, CLU, APP, CD14, ABCA7, AKAP9 and APOE mRNA levels, and ABCA7 and AKAP9 eQTLs, achieved 77% area under the curve to discriminate AD vs. CU, an 8% improvement over a model that only included age, sex and APOE-ε4 dosage.InterpretationIncorporating plasma mRNA levels could contribute to improved predictive value of AD biomarker panels.FundingThis work was supported by the National Institute on Aging [RF AG051504, U01 AG046139, R01 AG061796 to NET; P30 AG062677 to JAL and NGR]; Florida Health Ed and Ethel Moore Alzheimer's Disease grants [5AZ03 and 7AZ17 to NET; 7AZ07 to MMC; 8AZ08 to JAL].

Absence of tissue transglutaminase reduces amyloid-beta pathology in APP23 mice.

AimsAlzheimer's disease (AD) is characterised by amyloid‐beta (Aβ) aggregates in the brain. Targeting Aβ aggregates is a major approach for AD therapies, although attempts have had little to no success so far. A novel treatment option is to focus on blocking the actual formation of Aβ multimers. The enzyme tissue transglutaminase (TG2) is abundantly expressed in the human brain and plays a key role in post‐translational modifications in Aβ resulting in covalently cross‐linked, stable and neurotoxic Aβ oligomers.In vivo absence of TG2 in the APP23 mouse model may provide evidence that TG2 plays a key role in development and/or progression of Aβ‐related pathology.MethodsHere, we compared the effects on Aβ pathology in the presence or absence of TG2 using 12‐month‐old wild type, APP23 and a crossbreed of the TG2−/− mouse model and APP23 mice (APP23/TG2−/−).ResultsUsing immunohistochemistry, we found that the number of Aβ deposits was significantly reduced in the absence of TG2 compared with age‐matched APP23 mice. To pinpoint possible TG2‐associated mechanisms involved in this observation, we analysed soluble brain Aβ1–40, Aβ1–42 and/or Aβ40/42 ratio, and mRNA levels of human APP and TG2 family members present in brain of the various mouse models. In addition, using immunohistochemistry, both beta‐pleated sheet formation in Aβ deposits and the presence of reactive astrocytes associated with Aβ deposits were analysed.ConclusionsWe found that absence of TG2 reduces the formation of Aβ pathology in the APP23 mouse model, suggesting that TG2 may be a suitable therapeutic target for reducing Aβ deposition in AD.

Targeting hippocampal amyloidogenesis with SV2A protein modulator levetiracetam

Cerebral amyloid β (Aβ) proteostasis is compromised under neuronal overexcitation, long-term neuroinflammation and brain aging. Using the animal model of LPS-induced neuroinflammation we demonstrated that treatment with levetiracetam, a specific modulator of synaptic vesicle glycoprotein SV2A, rescues abnormal synaptic vesicle (SV) fusion and neurotransmitter release, decreasing elevated hippocampal APP levels in vivo. Therapy with levetiracetam upregulates the SV2A in hippocampus and restores the level of apolipoprotein E, involved in brain Aβ aggregation/clearance and resolution of inflammation.We demonstrated that oligomers of Aβ1-42 and Aβ1-40 peptides promote SV clustering, which reduces the rate and plateau level of subsequent homo- and heterotypic SNARE-mediated SV fusion. Oligomeric Aβ1-42 lowered ΔpH gradient across the vesicular membrane, thus affecting their neurotransmitter storage capacity. In contrast, monomers of Aβ1-42 and Aβ1-40 had negligible impact on studied processes.Our data suggests that in the course of progression of neuroinflammation oligomeric forms of Aβ1-42 and Aβ1-40 can compromise the SV fusion machinery and that antiepileptic agent levetiracetam, acting on SV recycling and restricting overexcitation, is able to affect APP processing and Aβ generation within the hippocampus in vivo.

Sex Differences in Behavior and Molecular Pathology in the 5XFAD Model.

The prevalence of Alzheimer's disease (AD) is greater in women compared to men, but the reasons for this remain unknown. This sex difference has been widely neglected in experimental studies using transgenic mouse models ofAD. Here, we studied behavior and molecular pathology of 5-month-old 5XFAD mice, which express mutated human amyloid precursor protein and presenilin-1 on a C57BL/6J background, versus their wild-type littermate controls, to compare both sex- and genotype-dependent differences. A novel behavioral paradigm was utilized (OF-NO-SI), comprising activity measures (Open Field, OF) arena, followed by Novel Object exploration (NO) and Social Interaction (SI) of a sex-matched conspecific. Each segment consisted of two repeated trials to assess between-trial habituation. Subsequently, brain pathology (amyloid load, stress response and inflammation markers, synaptic integrity, trophic support) was assessed using qPCR and western blotting. Female 5XFAD mice had higher levels of human APP and amyloid-β and heightened inflammation versus males. These markers correlated with hyperactivity observed in both sexes, yet only female 5XFAD mice presented with subtle deficits in object and social exploration. Male animals had higher expression of stress markers and neurotrophic factors irrespective of genotype, this correlated with cognitive performance. The impact of sex on AD-relevant phenotypes is in line with human data and emphasizes the necessity of appropriate study design and reporting. Differential molecular profiles observed in male versus female mice offer insights into possible protective mechanisms, and hence treatment strategies.

Fingolimod Rescues Memory and Improves Pathological Hallmarks in the 3xTg-AD Model of Alzheimer\u2019s Disease

Therapeutic strategies for Alzheimer’s disease (AD) have largely focused on the regulation of amyloid pathology while those targeting tau pathology, and inflammatory mechanisms are less explored. In this regard, drugs with multimodal and concurrent targeting of Aβ, tau, and inflammatory processes may offer advantages. Here, we investigate one such candidate drug in the triple transgenic 3xTg-AD mouse model of AD, namely the disease-modifying oral neuroimmunomodulatory therapeutic used in patients with multiple sclerosis, called fingolimod. In this study, administration of fingolimod was initiated after behavioral symptoms are known to emerge, at 6 months of age. Treatment continued to 12 months when behavioral tests were performed and thereafter histological and biochemical analysis was conducted on postmortem tissue. The results demonstrate that fingolimod reverses deficits in spatial working memory at 8 and 12 months of age as measured by novel object location and Morris water maze tests. Inflammation in the brain is alleviated as demonstrated by reduced Iba1-positive and CD3-positive cell number, less ramified microglial morphology, and improved cytokine profile. Finally, treatment with fingolimod was shown to reduce phosphorylated tau and APP levels in the hippocampus and cortex. These results highlight the potential of fingolimod as a multimodal therapeutic for the treatment of AD.

NEP1-40-overexpressing Neural Stem Cells Enhance Axon Regeneration by Inhibiting Nogo-A/NgR1 Signaling Pathway.

Nogo-66 antagonistic peptide (NEP1-40) offers the potential to improve spinal cord injury (SCI). To explore the effect of NEP1-40 overexpression on neural stem cells (NSCs) regulating the axon regeneration of injured neurons. We isolated NSCs from brain tissues of pregnant rat fetuses and used Nestin immunofluorescence to identify them. The NEP1-40 overexpressing NSCs were constructed by transfection with the NEP1-40-overexpressing vector. The expression of NSCs differentiation associated markers, including Tuj-1, GFAP, Oligo2, and MBP, were detected by RT-PCR, western blotting, and immunofluorescence. NeuN immunofluorescence staining was used to measure the number of neurons. And western blotting was used to detect the phosphorylation levels of LIMK1/2, cofilin, and MLC-2 and the protein levels of GAP-43, MAP-2, and APP. The NEP1-40 overexpression promoted the expression level of Tuj-1, Oligo2, and MBP, and increased the number of Tuj-1, Oligo2, and MBP positive cells. NEP1-40-overexpressing NSCs (NEP-NSCs) improved NeuN positive cells of co-culture with injured neurons. And NEP-NSCs also increased the protein levels of axon regeneration indicators (GAP-43, MAP-2) and decreased APP protein level. In addition, the phosphorylation level of LIMK1/2, cofilin, and MLC-2 were markedly decreased in NEP-NSCs. NEP1-40 overexpression enhanced the ability of NSCs differentiation into neurons and promoted axon regeneration by inhibiting the Nogo-A/NgR1 signaling pathway. This study provides an alternative gene modified transplantation NSCs for the SCI treatment.

Pengembangan aplikasi “CPA” (Covid-19 prevention application) sebagai literasi mitigasi bencana covid-19 bagi siswa SMP

The Covid-19 pandemic has brought major changes, including education where most learning activities are conducted online. It is thus necessary to adapt into online learning policies where innovation is urgently needed. Among the innovations is an e-book titled Covid-19 Prevention Application (CPA) that contains Covid-19 disaster mitigation literacy for students. This research aims to: 1) produce an app for CPA; and 2) test the feasibility level of CPA app as a learning resource. The material in CPA app relates to disaster mitigation, linked to the Social Studies Learning for junior high schools, namely Social Change for the 9th graders (Class IX.1) at SMPN 21 Malang. This research and development modified Borg & Gall model, which is relevant to constructivism learning theory, Edgar Dale’s theory of experience, and cybernetic learning theory. Results show that the development of the CPA app is “highly feasible”. This result implied that CPA app offers solutions to help students in mitigating the Covid-19 disaster through creative learning. It is suggested that further large-scale trials will be conducted in the future to measure the level of effectiveness.