Pathological Effects Research Articles

Reduced Graphene Oxide-Substituted Nanohydroxyapatite: Rejuvenating Bone-Nerve Crosstalk with Electrical Cues in a Fragility Fracture Rat Model under Hyperglycemia.

Diabetes has currently acquired the status of epidemic worldwide, and among its various pathological consequences like retinopathy and nephropathy, bone fragility fractures from diabetic osteopathy occurs in later stages and is equally destructive. Chronic hyperglycemia culminates into deteriorating microvasculature and quality of bone, making it prone to fractures. Among these, hip fractures are most common, especially in older diabetic patients apart from underlying neuropathy. Our study is an attempt to ameliorate hip fragility fracture and nerve trauma with electrical stimulation as an interface in a chronic diabetic rat model. We have fabricated reduced graphene oxide-substituted hydroxyapatite as an electroactive bone substitute and incorporated it into chitosan gelatin cryogels. The in situ reduction of graphene oxide during sintering of hydroxyapatite imparts higher potential to the fabricated composite in dealing with problem at question. The cryogels depicted optimum in vitro biocompatibility and enhanced mineralization after ectopic subcutaneous implantation in rats. The therapeutic potency of composite cryogels was evaluated in a hip fracture model with compression to the sciatic nerve in diabetic rats, mimicking the severe clinical trauma. The presence of cryogels in the femoral neck canal coupled with electrical stimulation and biochemical factors significantly improved bone regeneration in diabetic rats as depicted with microcomputed tomography analysis and histology images. The application of electrical stimulation also ameliorated the nerve trauma observed with 70% improvement in electrophysiological parameters such as the compound muscle action potential with combinatorial therapy. We therefore report the successful implication of a multitarget therapy in a chronic diabetic rat model unraveling the bone-nerve crosstalk with electroactive smart cryogels.

Investigating the effect of chronic stress, depressive-like pathology and cognitive impairments on acute myocardial infarction: sex-differentiated effects

Abstract Background/Introduction Depression is an independent risk factor for cardiovascular disease (CVD) with the prevalence rates being higher in women than men in the general population and among patients with CVD. Furthermore, an association between myocardial infarction and cognitive deficits has been proposed, but the pathophysiological mechanisms that are responsible for the brain-heart axis interaction have not been elucidated. Purpose The present study aims to: 1) evaluate sex differences in the effect of chronic unpredictable stress (CUS) on myocardial infarct size (IS) and 2) determine the molecular pathways affected by CUS in the heart. Methods Adult male and female C57BL/6J mice, were randomly divided into 4 groups (n=7/group): CON (Control, sham surgery), iCON (Control, myocardial ischemia/reperfusion (IR)), STR (Stress, sham surgery) and iSTR (Stress, IR). Mice were intermittently exposed to the CUS protocol consisted of 4 different stressors for 6 consecutive weeks. Locomotor activity (open field-OF), anxiety-like alterations (OF, elevated plus-maze-EPM test), depressive-like pathology (tail suspension test- TST) and cognition (Y-maze and Novel Object Recognition-NOR tests) were evaluated. After behavioral evaluation, the animals were subjected to 30 min I followed by 24 h of R or sham surgery and infarct size (IS) was determined via double Evan’s Blue and triphenyltetrazolium chloride staining. In a second series of experiments (n=5/group), the ischemic part of the myocardium was collected at 24h R and subjected to label free proteomic analysis, in order to identify alterations associated with the effect of CUS and IR. Results CUS induced anxiety, depressive-like pathology and cognitive deficits as indicated by the increased time spent in the closed arms of the EPM (p<0.005), the increased immobility time (TST, p<0.05), the reduced preference for the novel object (NOR, p<0.05), and the significant body weight reduction (p<0.001), in both male and female mice. CUS significantly increased IS (p<0.001) in both male and female mice. Proteomic analysis revealed that CUS affected the heart proteome, related to endoplasmic reticulum stress, mitochondrial damage and apoptosis, of both sexes in the absence of IR. Female mice were more susceptible to IR damage in absence of CUS with 248 significant genes (FDR<0.05) being deregulated mainly belonging to Keap-Nrf2-ARE signaling pathway, in contrast to 168 significant genes in male mice. In male mice, CUS exacerbated the IR injury proteome changes mainly related to induction of apoptosis and mitochondrial dysregulation (292 significant genes, FDR<0.05 for males vs 102 for females). Conclusions Chronic exposure to stress increases depressive-like pathology and cognitive deficits, leading to heart proteome alterations and increased IS in both sexes. Sex differences were observed indicating that the coexistence of CUS and IR render the male heart more susceptible to myocardial damage.

Effects of the restrictive cardiomyopathy-associated cardiac troponin I K178E mutation on cAMP signalling at the myofilament

Abstract Background Catecholaminergic stimulation of cardiac β-adrenergic receptors (β-ARs) and subsequent cAMP signalling control cardiac inotropy and lusitropy. cAMP signalling is known to be compartmentalised to optimise sympathetic control by producing heterogeneous cAMP signals and protein kinase A (PKA) activation at distinct subcellular sites. This signalling may be disrupted in diseases such as restrictive cardiomyopathy (RCM) characterised by diastolic dysfunction, which is associated with certain mutations including the K178E missense mutation in cardiac troponin I (TPNI). The impaired ventricular relaxation associated with this mutation is thought to arise from myofilament calcium hypersensitivity, which can be modulated by PKA-dependent TPNI phosphorylation. However, a detailed understanding of the pathological effects mediated by the K178E-TPNI mutation is lacking. Purpose This study aims to determine whether the K178E-TPNI mutation alters local cAMP/PKA signalling at TPNI, potentially affecting myofilament calcium sensitivity and cardiac myocyte relaxation. Methods Real-time imaging of cAMP was carried out using the Fluorescence Resonance Energy Transfer (FRET)-based sensor CUTie (cAMP Universal Tag for imaging experiments) [1] fused to wild type (WT)- or K178E-TPNI. The sensors were expressed by transfection in neonatal rat ventricular myocytes (NRVMs) and FRET-changes were recorded at the myofilament on application of the β-AR stimulant isoproterenol (ISO). We further assessed the involvement of cAMP hydrolysing phosphodiesterases (PDEs) in the regulation of cAMP levels selectively at TPNI. Results The peak FRET-change and FRET-change after 5mins on ISO application were significantly higher in NRVMs expressing the mutant compared to the WT sensor, as was the rate of cAMP accumulation. A strong trend showed that the rise in FRET following PDE4 inhibition was larger in NRVMs expressing the WT compared to the mutant sensor, suggesting the involvement of this isoform in degrading cAMP locally at TPNI and reduced PDE4 activity in the presence of the K178E mutation. Co-immunoprecipitation analysis in HEK293 cells demonstrated interaction between WT-TPNI and a PDE4D isoform, and a weaker interaction of this isoform with the K178E-TPNI mutant. Conclusions This study shows that the K178E-TPNI mutation attenuates the TPNI/PDE4D interaction and alters the magnitude and kinetics of the local cAMP response at the myofilament. This mechanistic insight may aid the development of therapeutics targeting the TPNI/PDE4D interaction to treat RCM-associated diastolic dysfunction.The TPNI-CUTie SensorFRET Response Trace

Permeability-Controlled Probe for Ratiometric Detection of Plasma Membrane Integrity and Late Apoptosis.

The destruction of plasma membrane integrity is closely related to immune response, neuronal injury, cell apoptosis, and other pathological events. However, the construction of ratiometric fluorescent probes capable of detecting plasma membrane integrity remains a significant challenge, hindering in-depth studies on related biomedical areas. Herein, a polarity-responsive fluorescent probe was constructed for the ratiometric detection of cell membrane integrity for the first time. The probe targeted intact plasma membranes in healthy cells and relocated into the cytoplasm to give significantly red-shifted fluorescence after plasma membrane damage. Molecular simulations revealed that the high transmembrane barrier and amphipathic nature of the probe were responsible for its targeting ability. With the probe, the ratiometric detection of late apoptosis stage was realized for the first time, and the membrane damage of tumor cells induced by UV irradiation, toxins, and antitumor drugs was visualized. The effect of formaldehyde on membrane integrity was evaluated using a probe, and cysteine was proved to be a potential detoxifier to counteract the toxicity of formaldehyde.

Association Between the Gut Microbiota and Alzheimer's Disease: An Update on Signaling Pathways and Translational Therapeutics.

Alzheimer's disease (AD) is a cognitive disease with high morbidity and mortality. In AD patients, the diversity of the gut microbiota is altered, which influences pathology through the gut-brain axis. Probiotic therapy alleviates pathological and psychological consequences by restoring the diversity of the gut microbial flora. This study addresses the role of altered gut microbiota in the progression of neuroinflammation, which is a major hallmark of AD. This process begins with the activation of glial cells, leading to the release of proinflammatory cytokines and the modulation of cholinergic anti-inflammatory pathways. Short-chain fatty acids, which are bacterial metabolites, provide neuroprotective effects and maintain blood‒brain barrier integrity. Furthermore, the gut microbiota stimulates oxidative stress and mitochondrial dysfunction, which promote AD progression. The signaling pathways involved in gut dysbiosis-mediated neuroinflammation-mediated promotion of AD include cGAS-STING, C/EBPβ/AEP, RAGE, TLR4 Myd88, and the NLRP3 inflammasome. Preclinical studies have shown that natural extracts such as Ganmaidazao extract, isoorentin, camelia oil, Sparassis crispa-1, and xanthocerasides improve gut health and can delay the worsening of AD. Clinical studies using probiotics such as Bifidobacterium spp., yeast beta-glucan, and drugs such as sodium oligomannate and rifaximine have shown improvements in gut health, resulting in the amelioration of AD symptoms. This study incorporates the most current research on the pathophysiology of AD involving the gut microbiota and highlights the knowledge gaps that need to be filled to develop potent therapeutics against AD.

Chemogenetic neuronal silencing decouples c-Jun activation from cell death in the temporal cortex.

Initial symptoms of neurodegenerative diseases are often defined by the loss of the most vulnerable neural populations specific to each disorder. In the early stages of Alzheimer's disease, vulnerable circuits in the temporal lobe exhibit diminished activity prior to overt degeneration. It remains unclear whether these functional changes contribute to regional vulnerability or are simply a consequence of pathology. We previously found that entorhinal neurons in the temporal cortex undergo cell death following transient suppression of electrical activity, suggesting a causal role for activity disruption in neurodegeneration. Here we demonstrate that electrical arrest of this circuit stimulates the injury-response transcription factor c-Jun. Entorhinal silencing induces transcriptional changes consistent with c-Jun activation that share characteristics of gene signatures in other neuronal populations vulnerable to Alzheimer's disease. Despite its established role in the neuronal injury response, inhibiting c-Jun failed to ameliorate entorhinal degeneration following activity disruption. Finally, we present preliminary evidence of integrated stress response activity that may serve as an alternative hypothesis to what drives entorhinal degeneration after silencing. Our data demonstrate that c-Jun is activated in response to neuronal silencing in the entorhinal cortex but is decoupled from subsequent neurodegeneration.

In Vivo Assessment of Deep Vascular Patterns in Murine Colitis Using Optoacoustic Mesoscopic Imaging.

The analysis of vascular morphology and functionality enables the assessment of disease activity and therapeutic effects in various pathologies. Raster-scanning optoacoustic mesoscopy (RSOM) is an imaging modality that enables the visualization of superficial vascular networks in vivo. In murine models of colitis, deep vascular networks in the colon wall can be visualized by transrectal absorber guide raster-scanning optoacoustic mesoscopy (TAG-RSOM). In order to accelerate the implementation of this technology in translational studies of inflammatory bowel disease, an image-processing pipeline for TAG-RSOM data has been developed. Using optoacoustic data from a murine model of chemically-induced colitis, different image segmentation methods are compared for visualization and quantification of deep vascular patterns in terms of vascular network length and complexity, blood volume, and vessel diameter. The presented image-processing pipeline for TAG-RSOM enables label-free in vivo assessment of changes in the vascular network in murine colitis with broad applications for inflammatory bowel disease research.

Genotype-phenotype analysis of hearing function in patients with DFNB1A caused by the c.-23+1G>A splice site variant of the GJB2 gene (Cx26).

The audiological features of hearing loss (HL) in patients with autosomal recessive deafness type 1A (DFNB1A) caused by splice site variants of the GJB2 gene are less studied than those of patients with other variants of this gene. In this study, we present the audiological features of DFNB1A in a large cohort of 134 patients with the homozygous splice site variant c.-23+1G>A and 34 patients with other biallelic GJB2 genotypes (n = 168 patients with DFNB1A). We found that the preservation of hearing thresholds in the speech frequency range (PTA0.5,1.0,2.0,4.0 kHz) in patients with the c.[-23+1G>A];[-23+1G>A] genotype is significantly better than in patients with the "severe" c.[35delG];[35delG] genotype (p = 0.005) and significantly worse than in patients with the "mild" c.[109G>A];[109G>A] genotype (p = 0.041). This finding indicates a "medium" pathological effect of this splice site variant on hearing function. A detailed clinical and audiological analysis showed that in patients with the c.[-23+1G>A];[-23+1G>A] genotype, HL is characterized as congenital or early onset (57.5% onset before 12 months), sensorineural (97.8%), bilateral, symmetrical (82.8%), variable in severity (from mild to profound HL, median hearing threshold in PTA0.5,1.0,2.0,4.0 kHz is 86.73±21.98 dB), with an extremely "flat" audioprofile, and with a tendency toward slow progression (a positive correlation of hearing thresholds with age, r = 0.144, p = 0.041). In addition, we found that the hearing thresholds in PTA0.5,1.0,2.0,4.0 kHz were significantly better preserved in females (82.34 dB) than in males (90.62 dB) (p = 0.001). We can conclude that in patients with DFNB1A caused by the c.-23+1G>A variant, male sex is associated with deteriorating auditory function; in contrast, female sex is a protective factor.

Injectable and pH-Responsive Metformin-Loaded Hydrogel for Active Inhibition of Posterior Capsular Opacification.

Posterior capsular opacification (PCO) is a common complication following cataract surgery, which can lead to a significant vision loss. This study introduces a facile method for developing a metformin-derived hydrogel (HCM6) stabilized by dynamic covalent bonds among natural polymers. This hydrogel demonstrates antifibrotic properties, on-demand drug release, pH responsiveness, injectability, and self-healing capabilities. Our in vitro experiments confirmed that the HCM6 hydrogel exhibits excellent biocompatibility, inhibiting lens epithelial cell migration, and transforming growth factor-2β (TGFβ2)-induced α-smooth muscle actin (α-SMA) expression in lens epithelial cells. In vivo studies conducted in a rat extracapsular lens extraction (ECLE) model revealed that HCM6 significantly suppressed PCO after 21 days of implantation with no observed pathological effects on surrounding tissues or the optic nerve. According to our experimental results, the inhibitory mechanism of PCO may be attributed to metformin's suppressive effect on lens cell migration, epithelial-mesenchymal transition (EMT), and lens fiber formation. In summary, the long-acting, controllable, and on-demand release characteristics of the HCM6 hydrogel not only provide an effective strategy for preventing PCO but also offer new avenues for treating undesirable proliferative conditions in ophthalmology and beyond.

Unravelling the Current Status of Rice Stripe Mosaic Virus: Its Geographical Spread, Biology, Epidemiology, and Management

Rice stripe mosaic virus (RSMV) belongs to the Cytorhabdovirus species in the Rhabdoviridae family. Recently, RSMV was widely spread in East Asia and caused severe yield losses. RSMV is transmitted by the planthopper vectors, Recilia dorsalis, Nephotettix virescens, and Nilaparvata lugens, that mostly affect rice. The adult vectors can hibernate, transmit the virus, lay eggs on rice plants, and, finally, multiply in subsequent generations, resulting in new infection outbreaks. RSMV-infected rice varieties display striped mosaicism, mild dwarfism, stiff and twisted leaves, delayed heading, short panicles with large unfilled grains, and yield reduction. In nature, the infection of multiple pathogens in the same host is widespread, which is defined as co-infection. It can be antagonistic or synergistic. Pathological synergistic effects between RSMV and other viruses can generate strains with new genetic characteristics, leading to unpredictable epidemiological consequences. After the first identification of RSMV in 2015, significant advancements in understanding the disease’s characteristics, symptoms, cycles, geographic distribution, potential vectors, and synergistic interaction, as well as its management strategies, were developed. To reduce the damage due to RSMV infection, many scientists have recommended pest control techniques to target adult vectors. It is also essential to confirm the actual time of monitoring, development of resistant varieties, and changes in cultivation systems. Due to the limitations of the conventional plant disease control technologies, improvements in efficiency and safety are in high demand. Therefore, to find efficient and environmentally safe controls to mitigate these challenges, reviews of research are the foremost step. In this review, we summarize the basic epidemiological information about the origin of RSMV and its infection symptoms in the field, synergistic interaction with viruses during co-transmission, yield losses, formulation of the disease cycle, and control strategies from several case studies. Finally, we recommend the formulation of the disease cycle and management strategies of RSMV infection.

Novel goose parvovirus in naturally infected ducks suffering from locomotor disorders: Molecular Detection, Histopathological examination, Immunohistochemical signals, and Full genome sequencing

In this study, we investigated the pathological effect of novel goose parvovirus (NGPV) infection on the skeletal muscle, brain, and intestine of naturally affected ducks suffering from locomotor dysfunction as a new approach for deeper understanding of such clinical form. For this purpose, a total of 97 diseased ducks, representing 24 flocks of different duck breeds (14-75 days old), were clinically examined. 72 tissue pools of intestine, brain, and skeletal muscle samples were submitted for molecular identification. Typical clinical signs among the examined ducks suggested the parvovirus infection. Regarding postmortem examination, all examined ducks showed muscle emaciation (100%) either accompanied by congestion (34%) or paleness (66%). Slight congestion, either in the brain (82.5%) or intestine (75.25%), was predominantly detected. Based on molecular identification, the intestine had the highest percentage of positive detection (91.7%), followed by the skeletal muscle (70.8%), and the brain (20.8%). The main histopathological alterations were myofiber atrophy and degeneration, marked enteritis accompanied by lymphocytic infiltration in the lamina propria and submucosa, while the affected brains showed vasculitis, diffuse gliosis, and Purkinje cell degeneration in the cerebellum. Next generation sequencing further confirmed the presence of a variant strain of goose parvovirus (vGPV) that is globally known as NGPV and closely related to Chinese NGPV isolates. Using immunohistochemistry, the NGPV antigen was positively detected in the muscle fibres, enterocytes, and Purkinje cells in the cerebellum. These findings provided proof of the involvement of virus replication in the locomotor disorders linked to NGPV infection in ducks.

Intranasal administration of GRP78 protein (HSPA5) counteracts the neurodegeneration in the locus coeruleus in a model of chronic sleep restriction in rats

Chronic sleep restriction (sleep less than 6 hours per day) due to the workload and a decrease in sleep quality is an endemic disease in modern society. Chronic sleep deprivation causes serious neuropsychiatric disorders associated with irreversible neurodegenerative changes in the brain. The search for pharmacological agents that can reduce the risk of neurodegeneration as a result of chronic sleep loss is an urgent task issue for biomedicine. Intranasal administration of glucose-regulated 78 kDa heat shock protein (GRP78) has a neuroprotective effect in a rat model of Parkinson´s disease. The neuroprotective potential of intranasally administered GRP78 in chronic sleep deprivation has not been previously studied. The aim of the study is to find out whether preventive intranasal administration of GRP78 is able to weaken and/or stop the process of neurodegeneration in the locus coeruleus in the model of chronic sleep restriction (SR) in rats. The study was conducted on 6 months old male Wistar rats. For sleep deprivation, a validated method of a swinging platform was used in the mode: 3 hours of sleep deprivation and 1 hour of rest continuously for 5 days. Recombinant human protein GRP78 was administered intranasally two days before the start of SR and during 5 days of SR. Cellular and molecular changes in the locus coeruleus during SR and during the administration of GRP78 were studied using immunohistochemistry and Western blotting. It was shown that chronic SR leads to the degeneration of 30% of noradrenergic neurons in the locus coeruleus, that was associated with an increase in the levels of activated caspases-3 and 9. This indicates the development of apoptosis along the mitochondrial pathway. No signs of reactive microgliosis were found in the model of chronic SR in rats. We have demonstrated that intranasally administered GRP78 penetrates and accumulates in the neurons of the locus coeruleus, GRP78 counteracts the death of neurons along the path of apoptosis. The data obtained allows to consider GRP78 as a potential neuroprotective agent for the prevention of pathological consequences of chronic sleep deprivation.

Associations between accelerated forgetting, amyloid deposition and brain atrophy in older adults.

Accelerated long-term forgetting (ALF) is the phenomenon whereby material is retained normally over short intervals (e.g. minutes) but forgotten abnormally rapidly over longer periods (days or weeks). ALF may be an early marker of cognitive decline, but little is known about its relationships with preclinical Alzheimer's disease pathology, and how memory selectivity may influence which material is forgotten. We assessed ALF in 'Insight 46', a sub-study of the MRC National Survey of Health and Development (a population-based cohort born during one week in 1946) (n=429; 47% female; assessed aged ∼73 years). ALF assessment comprised visual and verbal memory tests: Complex Figure Drawing and the Face-Name Associative Memory Exam (FNAME). ALF scores were calculated as the percentage of material retained after 7 days, relative to 30 minutes. In 306 cognitively-normal participants, we investigated effects on ALF of β-amyloid pathology (quantified using 18F-Florbetapir-PET, classified as positive/negative) and whole-brain and hippocampal atrophy rate (quantified from serial T1-MRI over ∼2.4 years preceding the ALF assessment), as well as interactions between these pathologies. We categorized Complex Figure Drawing items as 'outline' or 'detail', to test our hypothesis that forgetting the outline of the structure would be more sensitive to the effect of brain pathologies. We also investigated associations between ALF and Subjective Cognitive Decline, measured with the MyCog questionnaire. Complex Figure 'outline' items were better retained than 'detail' items (mean retention over 7 days = 94% vs 72%). Amyloid-positive participants showed greater forgetting of the Complex Figure outline, compared to amyloid-negatives (90% vs 95%; P<0.01). There were interactions between amyloid pathology and cerebral atrophy, such that whole-brain and hippocampal atrophy predicted greater ALF on Complex Figure Drawing among amyloid-positives only (e.g. 1.9 percentage-points lower retention per ml/year of whole-brain atrophy [95% confidence intervals 0.5, 3.7]; P<0.05). Greater ALF on FNAME was associated with increased rate of hippocampal atrophy. ALF on Complex Figure Drawing also correlated with subjective cognitive decline (-0.45 percentage-points per MyCog point [-0.85, -0.05], P<0.05). These results provide evidence of associations between some measures of ALF and biomarkers of brain pathologies and subjective cognitive decline in cognitively-normal older adults. On Complex Figure Drawing, 'outline' items were better remembered than 'detail' items - illustrating the strategic role of memory selectivity - but 'outline' items were also relatively more vulnerable to ALF in individuals with amyloid pathology. Overall, our findings suggest that ALF may be a sensitive marker of cognitive changes in preclinical Alzheimer's disease.

Heart-lung crosstalk in acute respiratory distress syndrome

Acute Respiratory Distress Syndrome (ARDS) is initiated by a primary insult that triggers a cascade of pathological events, including damage to lung epithelial and endothelial cells, extracellular matrix disruption, activation of immune cells, and the release of pro-inflammatory mediators. These events lead to increased alveolar-capillary barrier permeability, resulting in interstitial/alveolar edema, collapse, and subsequent hypoxia and hypercapnia. ARDS not only affects the lungs but also significantly impacts the cardiovascular system. We conducted a comprehensive literature review on heart-lung crosstalk in ARDS, focusing on the pathophysiology, effects of mechanical ventilation, hypoxemia, and hypercapnia on cardiac function, as well as ARDS secondary to cardiac arrest and cardiac surgery. Mechanical ventilation, essential for ARDS management, can increase intrathoracic pressure, decrease venous return and right ventricle preload. Moreover, acidemia and elevations in transpulmonary pressures with mechanical ventilation both increase pulmonary vascular resistance and right ventricle afterload. Cardiac dysfunction can exacerbate pulmonary edema and impair gas exchange, creating a vicious cycle, which hinders both heart and lung therapy. In conclusion, understanding the heart-lung crosstalk in ARDS is important to optimize therapeutic strategies. Future research should focus on elucidating the precise mechanisms underlying this interplay and developing targeted interventions that address both organs simultaneously.

Investigating the association between the GAP-43 concentration with diffusion tensor imaging indices in Alzheimer’s dementia continuum

BackgroundSynaptic degeneration, axonal injury, and white matter disintegration are among the pathological events in Alzheimer’s disease (AD), for which growth-associated protein 43 (GAP-43) and diffusion tensor imaging (DTI) could be an indicator. In this study, the cerebrospinal fluid (CSF) GAP-43 clinical trajectories and their association with progression and AD hallmarks with white matter microstructural changes were evaluated.MethodsA total number of 133 participants were enrolled in GAP-43 and DTI values were compared between groups, both cross-sectionally and longitudinally with two and four-year follow-ups. Subsequently, the correlation between GAP-43 levels in the CSF and DTI values was investigated using Spearman’s correlation.ResultsThe CSF level of GAP-43 is negatively correlated with the mean diffusivity measures in Fornix (Cres)/Stria terminals in early and late MCI (rs=-0.478 p = 0.021 and rs=-0.425 p = 0.038). Additionally, the CSF level of GAP-43 is negatively correlated with fractional anisotropy in the cingulum in late MCI (rs=-0.437 p = 0.033). Moreover, the axial diffusivity in superior corona radiate (rs=-0.562 p = 0.005 and rs=-0.484 p = 0.036) and radial diffusivity in superior fronto-occipital fasciculus was negatively correlated with GAP-43 level in the early and mid-MCI participants (rs=-0.520 p = 0.011 and rs=-0.498 p = 0.030).ConclusionsPresynaptic marker GAP-43 in combination with DTI can be used as a novel biomarker to identify microstructural synaptic degeneration in the early MCI. In addition, it can be used as a biomarker for tracking the progression of AD and monitoring treatment efficacy.

A Nitroreductase‐Activatable Metabolic Reporter for Covalent Labeling of Pathological Hypoxic Cells in Tumorigenesis

AbstractAberrant hypoxic stress will initiate a cascade of pathological consequence observed prominently in tumorigenesis. Understanding of hypoxia's role in tumorigenesis is highly essential for developing effective therapeutics, which necessitates reliable tools to specifically distinguish hypoxic tumor cells (or tissues) and correlate their dynamics with the status of disease in complex living settings for precise theranostics. So far, disparate hypoxia‐responsive probe molecules and prodrugs were designed via chemical or enzymatic reactions, yet their capability in real‐time reporting pathogenesis development is often compromised due to unrestricted diffusion and less selectivity towards the environmental responsiveness. Herein we present an oxygen‐insensitive nitroreductase (NTR)‐activatable glycan metabolic reporter (pNB‐ManNAz) capable of covalently labeling hypoxic tumor cells and tissues. Under pathophysiological hypoxic environments, the caged non‐metabolizable precursor pNB‐ManNAz exhibited unique responsiveness to cellular NTR, culminating in structural self‐immolation and the resultant ManNAz could incorporate onto cell surface glycoproteins, thereby facilitating fluorescence labeling via bioorthogonal chemistry. This NTR‐responsive metabolic reporter demonstrated broad applicability for multicellular hypoxia labeling, particularly in the dynamic monitoring of orthotopic tumorigenesis and targeted tumor phototherapy in vivo. We anticipate that this approach holds promise for investigating hypoxia‐related pathological progression, offering valuable insights for accurate diagnosis and treatment.

Unveiling the Interplay-Vitamin D and ACE-2 Molecular Interactions in Mitigating Complications and Deaths from SARS-CoV-2.

The interaction of the SARS-CoV-2 spike protein with membrane-bound angiotensin-converting enzyme-2 (ACE-2) receptors in epithelial cells facilitates viral entry into human cells. Despite this, ACE-2 exerts significant protective effects against coronaviruses by neutralizing viruses in circulation and mitigating inflammation. While SARS-CoV-2 reduces ACE-2 expression, vitamin D increases it, counteracting the virus's harmful effects. Vitamin D's beneficial actions are mediated through complex molecular mechanisms involving innate and adaptive immune systems. Meanwhile, vitamin D status [25(OH)D concentration] is inversely correlated with severity, complications, and mortality rates from COVID-19. This study explores mechanisms through which vitamin D inhibits SARS-CoV-2 replication, including the suppression of transcription enzymes, reduced inflammation and oxidative stress, and increased expression of neutralizing antibodies and antimicrobial peptides. Both hypovitaminosis D and SARS-CoV-2 elevate renin levels, the rate-limiting step in the renin-angiotensin-aldosterone system (RAS); it increases ACE-1 but reduces ACE-2 expression. This imbalance leads to elevated levels of the pro-inflammatory, pro-coagulatory, and vasoconstricting peptide angiotensin-II (Ang-II), leading to widespread inflammation. It also causes increased membrane permeability, allowing fluid and viruses to infiltrate soft tissues, lungs, and the vascular system. In contrast, sufficient vitamin D levels suppress renin expression, reducing RAS activity, lowering ACE-1, and increasing ACE-2 levels. ACE-2 cleaves Ang-II to generate Ang(1-7), a vasodilatory, anti-inflammatory, and anti-thrombotic peptide that mitigates oxidative stress and counteracts the harmful effects of SARS-CoV-2. Excess ACE-2 molecules spill into the bloodstream as soluble receptors, neutralizing and facilitating the destruction of the virus. These combined mechanisms reduce viral replication, load, and spread. Hence, vitamin D facilitates rapid recovery and minimizes transmission to others. Overall, vitamin D enhances the immune response and counteracts the pathological effects of SARS-CoV-2. Additionally, data suggests that widely used anti-hypertensive agents-angiotensin receptor blockers and ACE inhibitors-may lessen the adverse impacts of SARS-CoV-2, although they are less potent than vitamin D.

Pulling the Rug Out from Under: Biomechanical Microenvironment Remodeling for Induction of Hepatic Stellate Cell Quiescence.

Hepatic fibrosis progresses concomitantly with a variety of biomechanical alternations, especially increased liver stiffness. These biomechanical alterations have long been considered as pathological consequences. Recently, growing evidence proposes that these alternations result in the fibrotic biomechanical microenvironment, which drives the activation of hepatic stellate cells (HSCs). Here, an inorganic ascorbic acid-oxidase (AAO) mimicking nanozyme loaded with liquiritigenin (LQ) is developed to trigger remodeling of the fibrotic biomechanical microenvironment. The AAO mimicking nanozyme is able to consume intracellular ascorbic acid, thereby impeding collagen I deposition by reducing its availability. Simultaneously, LQ inhibits the transcription of lysyl oxidase like 2 (LOXL2), thus impeding collagen I crosslinking. Through its synergistic activities, the prepared nanosystem efficiently restores the fibrotic biomechanical microenvironment to a near-normal physiological condition, promoting the quiescence of HSCs and regression of fibrosis. This strategy of remodeling the fibrotic biomechanical microenvironment, akin to "pulling the rug out from under", effectively treats hepatic fibrosis in mice, thereby highlighting the importance of tissue biomechanics and providing a potential approach to improve hepatic fibrosis treatment.

Nox4 is involved in acute kidney injury associated to intravascular hemolysis

Massive intravascular hemolysis occurs not unfrequently in many clinical conditions. Breakdown of erythrocytes promotes the accumulation of heme-derivates in the kidney, increasing oxidative stress and cell death, thus promoting acute kidney injury (AKI). NADPH oxidase 4 (Nox4) is a major source of reactive oxygen species (ROS) in the kidney, however it is unknown the role of Nox4 in hemolysis and whether inhibition of this enzyme may protect from heme-mediated injury. To answer these questions, we elicited intravascular hemolysis in wild type and Nox4 knockout mice. We also evaluated whether nephrotoxic effects of heme may be reduced by using Nox4 siRNA and pharmacologic inhibition with GKT137831, a Nox4 inhibitor, both in vivo and in cultured renal cells. Our results showed that induction of massive hemolysis elicited AKI characterized by loss of renal function, morphological alterations of the tubular epithelium and podocytes, oxidative stress, inflammation, mitochondrial dysfunction, blockade of autophagy and cell death. These pathological effects were significantly prevented in Nox4-deficient mice and in animals treated with GKT137831. In vitro studies showed that Nox4 disruption by specific siRNAs or Nox4 inhibitors declined heme-mediated ROS production and cell death. Our data identify Nox4 as a key enzyme involved in intravascular hemolysis-induced AKI. Thus, Nox4 inhibition may be a potential therapeutic approach to prevent renal damage in patients with severe hemolytic crisis.

Combination of Green Tea, Green Coffee, and Turmeric Extract Improve the THOC5 and AIF1, but not ACTA2 and CNN1 Gene Expression in the Aortic Tissue of Metabolic Syndrome Model

Metabolic syndrome (MetS) is a group of risk factors in the form of central obesity, insulin resistance, dyslipidemia, and hypertension, increasing oxidative stress. This pathological event leads to the development of cardiovascular disease, for instance, atherosclerosis. Besides modifiable risk factors, non-modifiable risk factors such as genetic factors also play a role in the formation of atherosclerosis in MetS conditions such as THOC5, AIF1, CNN1, and ACTA2. Recently, natural compound derivatives, such as epigallocatechin-3-gallate (EGCG), chlorogenic acid (CGA), and turmeric, have shown beneficial effects in MetS improvement. This study aimed to investigate the effect of green tea, green coffee, and turmeric extract on the expression of THOC5, AIF1, CNN1, and ACTA2 genes that contributed to atherosclerotic vasculopathy development in the MetS rat model. Twenty-five MetS rat models were grouped into 4 groups (n = 5): Standard control (SC), MetS (MetS), a combination of green tea, green coffee, and turmeric extract with treatment doses: 300/100/150 mg/BW(C1) and 400/200/250 mg/BW(C2) group. The THOC5, AIF1, CNN1, and ACTA2 expression were measured at the end of treatment periods. This study found that administering green tea, green coffee, and turmeric extract can lower the expression of THOC5, AIF1, CNN1, and ACTA2. The correlation test showed that there is a strong correlation between THOC5 and AIF1 gene expression, with positive value. In summary, the combined effects of green tea, green coffee, and curcumin extract show significant promise as a potential anti-atherosclerosis treatment by improve the THOC5 and AIF1, but not ACTA2 and CNN1 gene expression in the aortic tissue of metabolic syndrome model. HIGHLIGHTS Metabolic syndrome is a group of risk factors consist of central obesity, insulin resistance, dyslipidemia, and hypertension. Individuals with MetS have an increased risk of developing atherosclerotic cardiovascular disease. Besides modifiable risk factors, non-modifiable risk factors such as genetic factors also play a role in the formation of atherosclerosis in MetS conditions such as THOC5, AIF1, CNN1, and ACTA2. This study aimed to investigate the effect of green tea, green coffee, and turmeric extract on the expression of THOC5, AIF1, CNN1, and ACTA2 genes that contributed to atherosclerotic vasculopathy development in the MetS rat model. Administering green tea, green coffee, and turmeric extract can lower the expression of THOC5, AIF1, CNN1, and ACTA2. The correlation test showed that there is a strong correlation between THOC5 and AIF1 gene expression, with positive value. In summary, the combined effects of green tea, green coffee, and curcumin extract show significant promise as a potential anti-atherosclerosis treatment by improve the THOC5 and AIF1, but not ACTA2 and CNN1 gene expression in the aortic tissue of metabolic syndrome model. GRAPHICAL ABSTRACT