miR-129 Promotes the Proliferation of Alzheimer’s Neuronal Cells by Binding the 3′ Untranslated Regions (3′ UTR) of Amyloid Precursor Protein (APP)

Alzheimer’s disease (AD) is a neurodegenerative disease with memory loss and cognitive impairment. Short non-coding RNAs (miRNAs) are potential biomarkers and therapeutic targets for AD. This study aims to investigate miR-129’s role in AD. miR-129 and amyloid precursor protein (APP) expression was measured by Q-PCR, and LC3, p62, ATG5, Bcl-2, p-Tau and Caspase3 protein was detected by Western blot. Hydrogenase kits and DCFH-DA detected cell apoptosis, cytotoxicity and ROS generation. The interaction between APP and miR-129 was assessed by luciferase report experiment. HE staining and TUNEL assay evaluated hippocampal neuron damage. In AD patient serum, AD transgenic (TG) mouse brain tissue, and AB1-42-treated SH-SY5Y cells, miR-129 was downregulated but autophagy was increased. Overexpression of miR-129 reduced cell damage induced by AB1-42, and miR-129 can directly regulate APP expression by binding APP 3′-UTR. miR-129 inhibitors reversed the protective effect of shAPP on AB1-42-induced cell damage. In addition, miR-129 overexpression reduced neuronal damage through inhibiting autophagy in vivo. APP expression in AD patient and AD cell model was significantly increased compared to controls. Aβ-42 treatment caused up-regulation of APP expression, while APP knockdown inhibited neurons through autophagy. In conclusion, miR-129 overexpression can regulate autophagy by targeting APP5, thereby reducing neuronal damage in AD. These findings provide a new perspective for treating AD.

Adult Hippocampal Neurogenesis in Alzheimer’s Disease: An Overview of Human and Animal Studies with Implications for Therapeutic Perspectives Aimed at Memory Recovery

The mammalian hippocampal dentate gyrus is a niche for adult neurogenesis from neural stem cells. Newborn neurons integrate into existing neuronal networks, where they play a key role in hippocampal functions, including learning and memory. In the ageing brain, neurogenic capability progressively declines while in parallel increases the risk for developing Alzheimer’s disease (AD), the main neurodegenerative disorder associated with memory loss. Numerous studies have investigated whether impaired adult neurogenesis contributes to memory decline in AD. Here, we review the literature on adult hippocampal neurogenesis (AHN) and AD by focusing on both human and mouse model studies. First, we describe key steps of AHN, report recent evidence of this phenomenon in humans, and describe the specific contribution of newborn neurons to memory, as evinced by animal studies. Next, we review articles investigating AHN in AD patients and critically examine the discrepancies among different studies over the last two decades. Also, we summarize researches investigating AHN in AD mouse models, and from these studies, we extrapolate the contribution of molecular factors linking AD-related changes to impaired neurogenesis. Lastly, we examine animal studies that link impaired neurogenesis to specific memory dysfunctions in AD and review treatments that have the potential to rescue memory capacities in AD by stimulating AHN.

Helicobacter Pylori Urease: Potential Contributions to Alzheimer’s Disease

Alzheimer’s disease (AD) causes dementia and memory loss in the elderly. Deposits of beta-amyloid peptide and hyperphosphorylated tau protein are present in AD’s brain. A filtrate of Helicobacter pylori’s culture was previously found to induce hyperphosphorylation of tau in vivo, suggesting that bacterial exotoxins could permeate the blood brain barrier and directly induce tau’s phosphorylation. H. pylori, which infects ~60% of the world population and causes gastritis and gastric cancer, produces a pro-inflammatory urease (HPU). Here the neurotoxic potential of HPU was investigated in cultured cells and in rats. SH-SY5Y neuroblastoma cells exposed HPU (50-300 nM) produced reactive oxygen species (ROS) and had an increased [Ca2+]i. HPU-treated BV-2 microglial cells produced ROS, cytokines IL-1β and TNF-α, expressed Iba1 and showed reduced viability, consistent with a neurotoxic effect of HPU. Rats received daily i.p. HPU (5 µg) for 7 days. Hyperphosphorylation of tau at Thr205, Ser199 and Ser396 sites was seen in hippocampal homogenates of treated rats, with no alterations in total tau or GSK-3b levels. HPU was not detected in the brain homogenates. Behavioral tests were performed to assess cognitive impairments. Our findings support previous data suggesting an association between infection by H. pylori and tauopathies such as AD, possibly mediated by its urease.

Clinical Features and Therapeutic Effects of Anti-leucine-rich Glioma Inactivated 1 Encephalitis: A Systematic Review

Background: Clinical presentations and treatment programs about anti-leucine-rich glioma inactivated 1 (LGI1) encephalitis still remain incompletely understood.Objective: This study analyzed the clinical features and therapeutic effects of anti-LGI1 encephalitis.Methods: PubMed, EMBASE, and the Cochrane Library were searched to identify published English and Chinese articles until April 2021. Data were extracted, analyzed, and recorded in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.Results: A total of 80 publications detailing 485 subjects matched our inclusion criteria. Short-term memory loss (75.22%), faciobrachial dystonic seizures (FBDS) (52.53%), other seizures excluding FBDS (68.48%), psychiatric symptoms (57.67%), and sleep disturbances (34.30%) were the most frequently described symptoms in anti-LGI1 encephalitis. Hyponatremia (54.90%) was the most common hematologic examination change. The risk of incidence rate of malignant tumors was higher than in healthy people. The positive rate of anti-LGI1 in serum (99.79%) was higher than CSF (77.38%). Steroids (93.02%), IVIG (87.50%), and combined use (96.67%) all had a high remission rate in the initial visit. A total of 35 of 215 cases relapsed, of which 6/35 (17.14%) did not use first-line treatment, and 21 (60.00%) did not maintain long-term treatment. Plasma exchange (PE) could be combined in severe patients, immunosuppressant could be used for refractory patients or for recurrence and using an anti-epileptic drug to control seizures may benefit cognition.Conclusions: Short-term memory loss, FBDS, psychiatric symptoms, and hyponatremia were key features in identifying anti-LGI1 encephalitis. Serum and CSF antibody tests should be considered in diagnosis criteria. Steroids with IVIG should be recommended, PE was combined for use in severe patients, immunosuppressant therapy might improve outcomes if recurrence or progression occurred, and control seizures might benefit cognition. The useful ways to reduce relapse rate were early identification, clear diagnosis, rapid treatment, and maintaining long-term treatment. The follow-up advice was suggested according to the research of paraneoplastic syndrome, and concern about tumors was vital as well.

Geraniol Attenuates Oxidative Stress and Neuro-inflammation Mediated Cognitive Impairment in D‑galactose‑induced Mouse Aging Model

D-galactose (D-gal) is a reducing sugar drug can induce artificial senescence and aging process that mimic natural aging along with the accompanying brain and liver injury in experimental animals. Therefore, chronic D-gal administration is widely used to induce cognitive impairment, Alzheimer disease and aging in rodents' models. Aging is a phenomenon in which oxidative stress and apoptosis play a vital role. Geraniol (GNL) belongs to the acyclic isoprenoid monoterpenes, presents in essential oils such as those from Cinnamomum tenuipilum and Valeriana officinalis. In the present study, we examined the effects of GNL on D-gal-induced oxidative stress and neuro-inflammation mediated memory loss in mice. Analyzing the behavioral differences between control and treated groups, including the elderly mice, revealed that GNL significantly improved memory in mice treated with D-gal-induced memory loss (supplementary videos are provided). The anti-inflammatory and the anti-oxidative role of GNL were confirmed by both histopathological investigations and biochemical analyses. Mechanistically, GNL appears to activate PI3K/Akt and thus upregulates the nuclear factor erythroid 2-related factor 2 (Nrf2) and the heme oxygenase 1 (HO-1) to reduce the oxidative stress and apoptosis induced after D-gal treatment leading to easing of neurological deficits and cognitive dysfunction in D-gal-induced aging mouse models. Accordingly, our comprehensive behavioral analysis and bioassays suggest GNL as a promising agent preventing cognitive impairment and neurological deficits associated with aging.

Adjunctive Magnetic Seizure Therapy for Schizophrenia: A Systematic Review

Objective: The efficacy and safety of adjunctive magnetic seizure therapy (MST) for patients with schizophrenia are unclear. This systematic review was conducted to examine the efficacy and safety of adjunctive MST for schizophrenia.Methods: Chinese (WanFang and Chinese Journal Net) and English (PubMed, EMBASE, PsycINFO, and the Cochrane Library) databases were systematically searched.Results: Two open-label self-controlled studies (n = 16) were included and analyzed in this review. In these studies, the Positive and Negative Syndrome Scale (PANSS) total scores and Brief Psychiatric Rating Scale (BPRS) total scores significantly decreased from baseline to post-MST (all Ps < 0.05), without serious adverse neurocognitive effects. Mixed findings on the neurocognitive effects of adjunctive MST for schizophrenia were reported in the two studies. A discontinuation rate of treatment of up to 50% (4/8) was reported in both studies. The rate of adverse drug reactions (ADRs) was evaluated in only one study, where the most common ADRs were found to be dizziness (25%, 2/8) and subjective memory loss (12.5%, 1/8).Conclusion: There is inconsistent evidence for MST-related adverse neurocognitive effects and preliminary evidence for the alleviation of psychotic symptoms in schizophrenia.

Neurotoxic Amyloidogenic Peptides in the Proteome of SARS-COV2: Potential Implications for Neurological Symptoms in COVID-19

COVID-19 is primarily known as a respiratory disease caused by the virus SARS-CoV-2. However, neurological symptoms such as memory loss, sensory confusion, cognitive and psychiatric issues, severe headaches, and even stroke are reported in as many as 30% of cases and can persist even after the infection is over (so-called ‘long COVID’). These neurological symptoms are thought to be caused by brain inflammation, caused by the virus infecting the central nervous system of COVID-19 patients, however we still don’t understand the molecular mechanisms that trigger these symptoms. The neurological effects of COVID-19 share many similarities to neurodegenerative diseases such as Alzheimer’s and Parkinson’s in which the presence of cytotoxic protein-based amyloid aggregates is a common etiological feature. Following the hypothesis that some neurological symptoms of COVID-19 may also follow an amyloid etiology we performed a bioinformatic scan of the SARS-CoV-2 proteome, detecting peptide fragments that were predicted to be highly amyloidogenic. We selected two of these peptides from the open reading frame 6 (ORF6) and open reading frame 10 (ORF10) proteins. The amyloidogenic virus-derived proteins studied in this work did not include spike (S) protein or any other proteins that have been modified to function as antigens in any current vaccines. We discovered that these ORF protein fragments rapidly self-assemble into amyloid aggregates. Furthermore, these amyloid assemblies were shown to be highly toxic to a neuronal cell line. We introduce and support the idea that cytotoxic amyloid aggregates of SARS-CoV-2 proteins are causing some of the neurological symptoms commonly found in COVID-19 and contributing to long COVID.

Amelioration of Alzheimer’s disease pathology by mitophagy inducers identified via machine learning and a cross-species workflow

A reduced removal of dysfunctional mitochondria is common to aging and age-related neurodegenerative pathologies such as Alzheimer’s disease (AD). Strategies for treating such impaired mitophagy would benefit from the identification of mitophagy modulators. Here we report the combined use of unsupervised machine learning (involving vector representations of molecular structures, pharmacophore fingerprinting and conformer fingerprinting) and a cross-species approach for the screening and experimental validation of new mitophagy-inducing compounds. From a library of naturally occurring compounds, the workflow allowed us to identify 18 small molecules, and among them two potent mitophagy inducers (Kaempferol and Rhapontigenin). In nematode and rodent models of AD, we show that both mitophagy inducers increased the survival and functionality of glutamatergic and cholinergic neurons, abrogated amyloid-β and tau pathologies, and improved the animals’ memory. Our findings suggest the existence of a conserved mechanism of memory loss across the AD models, this mechanism being mediated by defective mitophagy. The computational–experimental screening and validation workflow might help uncover potent mitophagy modulators that stimulate neuronal health and brain homeostasis.

Dysbiosis in Alzheimer’s Disease Might be Triggered by Certain Classes of Antibiotics with Time-lapse: New Insights in the Pathogenesis?

Background and objectives: Alzheimer's disease (AD) is a progressive neurodegenerative illness, responsible for 60-70% of all dementias, affecting over 50 million people worldwide, and nearly 11 million in European countries. Several putative factors are identified in the literature as causative agents or risk factors for the development of AD. The amyloid cascade hypothesis has been the main hypothesis about the pathophysiology of AD for decades. Recent studies raised the possible role of dysbiosis in the development of AD which prevents memory loss. The amyloid-β (Aβ) deposition might be considered as an inflammatory reaction to certain molecular products arising from the altered microbiome. Based on the above observations, it has been suspected, that antibiotic consumption patterns of different antibiotic classes might be associated with the prevalence of AD in European countries. Methods: Antibiotic consumption (ECDC) for 1997-2007, 2008-2018, and as the whole 1997-2018 period, have been compared to the AD prevalence for 2018 expressed in percentage of the population and statistically analyzed by Pearson calculation. Results: A significant positive correlation has been found between the AD prevalence (2018) and the average quinolone consumption for the year 1997-2007 (p: 0.044). A similar association was not observed for the entire 22 years (1997-2018) of the average quinolone consumption, and the years 2008-18, indicating 10-20 years of time-lapse between the antibiotic exposure and the development of AD. The ratio of broad-spectrum and narrow-spectrum antibiotics (B/N) estimated in the ECDC database for the years of 2008-2018 showed a strong positive association with AD prevalence (2018) (p: 0.026) and a positive correlation tendency for the entire 22 years 1997-2018 (p: 0.063), but none for the years 1997-2007 (p: 0.241). Broad-spectrum, beta-lactamase sensitive penicillin (J01CA) consumption showed a positive (non-significant) correlation with the prevalence of AD for the years 2008-2018 (p:0.080).Discussion: Our study indicated the possible sequential role of certain classes of antibiotics in the development of dysbiosis leading to amyloid deposits of AD, which strengthen the possible role of different mediator molecules (short-chain fatty acids, lipopolysaccharides, etc.) produced by the altered microbiome in the development of AD.