Impaired Hippocampal Reactivation Preceding Robust Aß Deposition in a Model of Alzheimer's Disease.

Current therapeutic strategies for Alzheimer's disease (AD) target amyloid-beta (Aß) fibrils and high molecular weight protofibrils associated with plaques, but other bioactive species may directly contribute to neural systems failure in AD. Employing hippocampal electrophysiological recordings and dynamic calcium imaging across the sleep-wake cycle in young mice expressing human Aß and Aß oligomers, we reveal marked impairments of hippocampal function long before amyloid plaques predominate. In slow wave sleep (SWS), Aß increased the proportion of hypoactive cells and reduced place-cell reactivation. During awake behavior, Aß impaired theta-gamma phase-amplitude coupling (PAC) and drove excessive synchronization of place cell calcium fluctuations with hippocampal theta. Remarkably, the on-line impairment of hippocampal theta-gamma PAC correlated with the SWS impairment of place-cell reactivation. Together, these results identify toxic effects of Aß on memory encoding and consolidation processes before robust plaque deposition and support targeting soluble Aß-related species to treat and prevent AD.

Cellular resolution contributions to ictal population signals.

OBJECTIVE: The increased amplitude of ictal activity is a common feature of epileptic seizures, but the determinants of this amplitude have not been identified. Clinically, ictal amplitudes are measured electrographically (using, e.g., electroencephalography, electrocorticography, and depth electrodes), but these methods do not enable the assessment of the activity of individual neurons. Population signal may increase from three potential sources: (1) increased synchrony (i.e., more coactive neurons); (2) altered active state, from bursts of action potentials and/or paroxysmal depolarizing shifts in membrane potential; and (3) altered subthreshold state, which includes all lower levels of activity. Here, we quantify the fraction of ictal signal from each source. METHODS: To identify the cellular determinants of the ictal signal, we measured single cell and population electrical activity and neuronal calcium levels via optical imaging of the genetically encoded calcium indicator (GECI) GCaMP. Spontaneous seizure activity was assessed with microendoscopy in an APP/PS1 mouse with focal cortical injury and via widefield imaging in the organotypic hippocampal slice cultures (OHSCs) model of posttraumatic epilepsy. Single cell calcium signals were linked to a range of electrical activities by performing simultaneous GECI-based calcium imaging and whole-cell patch-clamp recordings in spontaneously seizing OHSCs. Neuronal resolution calcium imaging of spontaneous seizures was then used to quantify the cellular contributions to population-level ictal signal. RESULTS: The seizure onset signal was primarily driven by increased subthreshold activity, consistent with either barrages of excitatory postsynaptic potentials or sustained membrane depolarization. Unsurprisingly, more neurons entered the active state as seizure activity progressed. However, the increasing fraction of active cells was primarily driven by synchronous reactivation and not from continued recruitment of new populations of neurons into the seizure. SIGNIFICANCE: This work provides a critical link between single neuron activity and population measures of seizure activity.

Germination Increases the Glucomoringin Content in Moringa Sprouts via Transforming Tyrosine.

Moringa seeds are an excellent dietary source of phytochemicals (i.e., glucosinolates, GSLs; isothiocyanates, ITCs) with health-beneficial effects. Although numerous studies have been conducted on moringa seeds, the effect of germination on the regulation of GSLs remains scarcely explored. The present study investigated the dynamic changes of GSLs in moringa seeds during germination (at 25, 30, and 35 °C for 6 days in the dark) through an untargeted metabolomics approach and compared the antioxidant capacity of ungerminated and germinated moringa seeds. Our results showed that germination significantly increased the total GSL content from 150 (day 0) to 323 µmol/g (35 °C, day 6) on a dry weight (DW) basis, especially glucomoringin (GMG), the unique glucosinolate in moringa seeds, which was significantly upregulated from 61 (day 0) to 149 µmol/g DW (35 °C, day 4). The upregulation of GMG corresponded to the metabolism of tyrosine, which might be the initial precursor for the formation of GMG. In addition, germination enhanced the total ITC content from 85 (day 0) to 239 µmol SE/g DW (35 °C, day 6), indicating that germination may have also increased the activity of myrosinase. Furthermore, germination remarkably increased the total phenolic content (109-507 mg GAE/100 g DW) and antioxidant capacity of moringa seeds. Our findings suggest that moringa sprouts could be promoted as a novel food and/or ingredient rich in GMG.

Guide for phenotype-specific profiling of DNA G-quadruplex-regulated genes.

DNA G-quadruplex (G4) is a non-canonical four-stranded secondary structure that has been shown to play a role in epigenetic modulation of gene expression. Here, we present a primer on phenotype-specific profiling of DNA G-quadruplex-regulated genes. We provide guidance on in silico exploration of G4-related genes and phenotypes, and in vitro and in vivo validation of the relationship between G4 and phenotype. We describe commonly utilized techniques and detail critical steps involved in determining the phenotype-specific G4-regulated genes for subsequent investigations.

Serglycin secreted by late-stage nucleus pulposus cells is a biomarker of intervertebral disc degeneration.

Intervertebral disc degeneration is a natural process during aging and a leading cause of lower back pain. Here, we generate a comprehensive atlas of nucleus pulposus cells using single-cell RNA-seq analysis of human nucleus pulposus tissues (three males and four females, age 41.14 ± 18.01 years). We identify fibrotic late-stage nucleus pulposus cells characterized by upregulation of serglycin expression which facilitate the local inflammatory response by promoting the infiltration of inflammatory cytokines and macrophages. Finally, we discover that daphnetin, a potential serglycin ligand, substantially mitigates the local inflammatory response by downregulating serglycin expression in an in vivo mouse model, thus alleviating intervertebral disc degeneration. Taken together, we identify late-stage nucleus pulposus cells and confirm the potential mechanism by which serglycin regulates intervertebral disc degeneration. Our findings indicate that serglycin is a latent biomarker of intervertebral disc degeneration and may contribute to development of diagnostic and therapeutic strategies.

Acetylshikonin promoting PI3K/Akt pathway and inhibiting SOX4 expression to delay intervertebral disc degeneration and low back pain.

This study investigated the molecular mechanism by which acetylshikonin inhibits SOX4 expression via the PI3K/Akt pathway to delay intervertebral disc degeneration (IVDD) and low back pain (LBP). Bulk RNA-seq, RT-qPCR, Western blot analysis, immunohistochemical staining, small interfering RNA (siSOX4), lentivirus (lentiv-SOX4hi ), and imaging techniques were used to assess SOX4 expression and validate its upstream regulatory pathway. Acetylshikonin and siSOX4 were injected into the IVD to measure IVDD. SOX4 expression significantly increased in degenerated IVD tissues. TNF-α increased SOX4 expression and apoptosis-related proteins in nucleus pulposus cells (NPCs). siSOX4 reduced TNF-α-induced NPCs apoptosis, while Lentiv-SOX4hi increased it. The PI3K/Akt pathway was significantly correlated with SOX4, and acetylshikonin upregulated PI3K/Akt pathway while inhibiting SOX4 expression. In the anterior puncture IVDD mouse model, SOX4 expression was upregulated, and acetylshikonin and siSOX4 delayed IVDD-induced LBP. Acetylshikonin delays IVDD-induced LBP by inhibiting SOX4 expression through the PI3K/Akt pathway. These findings offer potential therapeutic targets for future treatments.

Clinical outcomes of conversion surgery following immune checkpoint inhibitors and chemotherapy in stage IV gastric cancer.

BACKGROUND: The clinical benefit of conversion surgery following immunochemotherapy in patients with stage IV gastric cancer (GC) remains uncertain. This study aims to clarify the clinical outcomes of conversion surgery for such patients. METHODS: This retrospective cohort study enroled consecutive patients with stage IV GC treated with a combination of immune checkpoint inhibitors and chemotherapy and/or anti-human epidermal growth factor receptor-2 targeted therapy as first-line therapy. Cumulative survival curves were estimated using Kaplan-Meier method. Logistic regression and Cox regression analyses were conducted to identify factors associated with conversion surgery and survival, respectively. RESULTS: Among the 136 patients included in the study. The disease control rate was 72.1% (98/136), with objective response rate in 58.8% (80/136) and complete response rate in 5.9% (8/136). Among 98 patients with disease control, 56 patients underwent palliative immunochemotherapy with median progression-free survival (PFS) and overall survival at 9.2 and 16.2 months, respectively; the remaining 42 patients underwent conversion surgery, yielding an unreached median PFS over a 19.0-month median follow-up, accompanied by 1-year overall survival and PFS rates of 96.6% and 89.1%, respectively. The R0 resection rate reached 90.5% (38/42). 7 out of 42 patients achieved pathological complete response, of whom three patients demonstrated human epidermal growth factor receptor-2 positivity. No serious complications leading to death were observed during the perioperative period. Multivariate analysis indicated that programmed death ligand 1 combined positive score greater than or equal to 5 (odds ratio, 0.22; 95% CI, 0.08-0.57; P =0.002) favored successful conversion surgery, while signet ring cell carcinoma (hazard ratio, 6.29; 95% CI, 1.56-25.36; P =0.010) was the poor prognostic factor associated with survival in patients who underwent conversion surgery. CONCLUSIONS: Conversion surgery holds the potential for significant survival benefits in stage IV GC patients who have achieved a favourable clinical response to immunochemotherapy. Individuals with signet ring cell carcinoma may experience increased post-conversion surgery recurrence.

Optogenetic targeting of astrocytes restores slow brain rhythm function and slows Alzheimer's disease pathology.

Patients with Alzheimer's disease (AD) exhibit non-rapid eye movement (NREM) sleep disturbances in addition to memory deficits. Disruption of NREM slow waves occurs early in the disease progression and is recapitulated in transgenic mouse models of beta-amyloidosis. However, the mechanisms underlying slow-wave disruptions remain unknown. Because astrocytes contribute to slow-wave activity, we used multiphoton microscopy and optogenetics to investigate whether they contribute to slow-wave disruptions in APP/PS1 mice. The power but not the frequency of astrocytic calcium transients was reduced in APP/PS1 mice compared to nontransgenic controls. Optogenetic activation of astrocytes at the endogenous frequency of slow waves restored slow-wave power, reduced amyloid deposition, prevented neuronal calcium elevations, and improved memory performance. Our findings revealed malfunction of the astrocytic network driving slow-wave disruptions. Thus, targeting astrocytes to restore circuit activity underlying sleep and memory disruptions in AD could ameliorate disease progression.

Optogenetic Targeting of Astrocytes Restores Slow Brain Rhythm Function and Slows Alzheimer's Disease Pathology.

Patients with Alzheimer's disease (AD) exhibit non-rapid eye movement (NREM) sleep disturbances in addition to memory deficits. Disruption of NREM slow waves occurs early in the disease progression and is recapitulated in transgenic mouse models of beta-amyloidosis. However, the mechanisms underlying slow-wave disruptions remain unknown. Because astrocytes contribute to slow-wave activity, we used multiphoton microscopy and optogenetics to investigate whether they contribute to slow-wave disruptions in APP mice. The power but not the frequency of astrocytic calcium transients was reduced in APP mice compared to nontransgenic controls. Optogenetic activation of astrocytes at the endogenous frequency of slow waves restored slow-wave power, reduced amyloid deposition, prevented neuronal calcium elevations, and improved memory performance. Our findings revealed malfunction of the astrocytic network driving slow-wave disruptions. Thus, targeting astrocytes to restore circuit activity underlying sleep and memory disruptions in AD could ameliorate disease progression.

Clinical atlas of rectal cancer highlights the barriers and insufficient interventions underlying the unfavorable outcomes in older patients.

Background: Aging confers an increased risk of developing cancer, and the global burden of cancer is cumulating as human longevity increases. Providing adequate care for old patients with rectal cancer is challenging and complex. Method: A total of 428 and 44,788 patients diagnosed with non-metastatic rectal cancer from a referral tertiary care center (SYSU cohort) and the Surveillance Epidemiology and End Results database (SEER cohort) were included. Patients were categorized into old (over 65 years) and young (aged 50-65 years) groups. An age-specific clinical atlas of rectal cancer was generated, including the demographic and clinicopathological features, molecular profiles, treatment strategies, and clinical outcomes. Results: Old and young patients were similar in clinicopathological risk factors and molecular features, including TNM stage, tumor location, tumor differentiation, tumor morphology, lymphovascular invasion, and perineural invasion. However, old patients had significantly worse nutritional status and more comorbidities than young patients. In addition, old age was independently associated with less systemic cancer treatment (adjusted odds ratio 0.294 [95% CI 0.184-0.463, P < 0.001]). We found that old patients had significantly worse overall survival (OS) outcomes in both SYSU (P < 0.001) and SEER (P < 0.001) cohorts. Moreover, the death and recurrence risk of old patients in the subgroup not receiving chemo/radiotherapy (P < 0.001 for OS, and P = 0.046 for time to recurrence [TTR]) reverted into no significant risk in the subgroup receiving chemo/radiotherapy. Conclusions: Although old patients had similar tumor features to young patients, they had unfavorable survival outcomes associated with insufficient cancer care from old age. Specific trials with comprehensive geriatric assessment for old patients are needed to identify the optimal treatment regimens and improve unmet cancer care. Study registration: The study was registered on the research registry with the identifier of researchregistry 7635.

Genomic G-quadruplex folding triggers a cytokine-mediated inflammatory feedback loop to aggravate inflammatory diseases.

DNA G-quadruplex is a non-canonical secondary structure that could epigenetically regulate gene expression. To investigate the regulating role of G-quadruplex, we devised an integrating method to perform the algorithm profiling and genome-wide analysis for the dynamic change of genomic G-quadruplex and RNA profiles in rat nucleus pulposus cells by inducing G-quadruplex folding with multiple stabilizers. A group of genes potentially regulated by G-quadruplex and involved in the inflammation process has been identified. We found that G-quadruplex folding triggers inflammation response by upregulating inflammatory cytokines, which could promote G-quadruplex folding in a manner of positive feedback loop. Moreover, we confirmed that G-quadruplex is a marker indicating elevated inflammatory status and G-quadruplex folding facilitates the development of inflammatory diseases using in vivo intervertebral disc degeneration models. The crosstalk between G-quadruplex and inflammatory cytokines plays a vital role in regulating inflammation-derived diseases, which may provide new insights into the blocking target.

Grem1 accelerates nucleus pulposus cell apoptosis and intervertebral disc degeneration by inhibiting TGF-ß-mediated Smad2/3 phosphorylation.

Intervertebral disc degeneration (IVDD) is a main cause of low back pain, and inflammatory factors play key roles in its pathogenesis. Gremlin-1 (Grem1) was reported to induce an inflammatory response in other fields. This study aimed to investigate the mechanisms of Grem1 in the degenerative process of intervertebral discs. Dysregulated genes were determined by analyzing microarray profiles. The expression of Grem1 in 17 human disc samples (male:female = 9:8) and rat models (n = 5 each group) was measured by western blotting (WB), real-time quantitative PCR (RT-qPCR), and immunohistochemistry (IHC). The regulatory effects of Grem1 on apoptosis were examined using siRNAs, flow cytometry, immunofluorescence (IF), and WB. The therapeutic effect was evaluated by locally injecting specific Grem1 siRNA into IVDD rats. The expression of Grem1 was significantly increased in human degenerative intervertebral discs; furthermore, the expression of Grem1 positively correlated with the level of intervertebral disc degeneration. Grem1 was significantly overexpressed in tumor necrosis factor (TNF)-α-induced degenerative NP cells. Apoptosis in degenerative NP cells transfected with siRNA targeting Grem1 was significantly lower than that in the control group. Specific Grem1 siRNA markedly repressed the development of IVDD in surgery-induced IVDD rats. These results indicated that the expression of Grem1 was positively correlated with the severity of intervertebral disc degeneration, and Grem1 siRNA could inhibit Grem1-induced apoptosis and extracellular matrix alterations by mediating the TGF-ß/Smad signaling pathway. This study may provide a therapeutic strategy for alleviating inflammation-induced apoptosis associated with intervertebral disc degeneration.

Region-specific deletions of the glutamate transporter GLT1 differentially affect nerve injury-induced neuropathic pain in mice.

Glutamate is a major excitatory neurotransmitter and plays an important role in neuropathic pain, which is frequently caused by nerve damage. According to recent studies, nerve injury induces changes in glutamatergic transmission in the spinal cord and several supraspinal regions, including the periaqueductal gray (PAG). Among glutamate signaling components, accumulating evidence suggests that the glial glutamate transporter GLT1 plays a critical role in neuropathic pain. Indeed, GLT1 expression is reduced in the spinal cord but increased in the PAG after nerve injury, suggesting that the role of GLT1 in neuropathic pain may vary according to the brain region. In this study, we generated PAG-specific and spinal cord-specific GLT1 knockout mice. Nerve injury-induced neuropathic pain was enhanced in spinal cord-specific GLT1 knockout mice but alleviated in PAG-specific GLT1 knockout mice. Thus, nerve injury may enhance glutamatergic neurotransmission from primary sensory neurons to the post-synaptic dorsal horn following downregulation of GLT1 in the spinal cord and result in inadequate descending pain inhibition caused by GLT1 upregulation in the PAG, resulting in neuropathic pain. In addition, ceftriaxone upregulated GLT1 expression in the spinal cord, but not the PAG, of control mice and attenuated tactile hypersensitivity in nerve-injured control mice but not in nerve-injured spinal cord-specific GLT1 knockout mice. Based on these results, the anti-neuropathic pain effect of ceftriaxone is mediated by the upregulation of GLT1 expression in the spinal cord. Thus, selective upregulation of spinal GLT1 and/or downregulation of GLT1 in the PAG represents a potentially novel strategy for the treatment of neuropathic pain.