Artificial Neutrophils Against Vascular Graft Infection.

Efficient neutrophil migration to infection sites plays a vital role in the body's defense against bacterial infections and natural immune responses. Neutrophils have a short lifespan and cannot be mass-cultured in vitro. Therefore, developing more stable artificial neutrophils (AN) in a controllable manner has become a research focus. However, existing AN lack chemotaxis, which is the ability to migrate toward high-signal-concentration positions in a dynamic blood- flow environment. Supplying AN with chemotaxis is key to designing AN that are more similar to natural neutrophils in terms of morphology and function. In this study, micrometer-sized, spherical, biocompatible AN are developed. These AN consist of zeolitic imidazolate framework-8 nanoparticles encapsulating two enzymes, coacervate droplet frameworks, and outer phospholipid bilayers carrying enzymes. The AN exhibit responsiveness to elevated hydrogen peroxide levels at inflammation sites, actively chemotaxing toward these sites along concentration gradients. They also demonstrate effective combat against Staphylococcus aureus infections. The capabilities of the AN are further validated through in vitro experiments and in vivo evaluations using vascular graft infection models. This study replicates natural neutrophils in terms of chemical composition, functionality, and physiological impact. It introduces new ideas for advancing the development of advanced artificial cells.

Neuroprotective Effects of Genistein in a SOD1-G93A Transgenic Mouse Model of Amyotrophic Lateral Sclerosis.

Oxidant toxicity has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS), an insidiously progressive neurodegenerative disorder involving upper and lower motor neurons. Here, we investigated the cellular and molecular mechanisms underlying the neuroprotective effects of an anti-oxidant genistein in SOD1-G93A transgenic mouse model of ALS. Rotarod test, hanging wire test and hindlimb clasping test were used to determined disease onset and assess motor performance. Immunostaining together with neuronal size measurement were used to count viable motor neurons. In addition, immunostaining procedure and ELISA kit were used to assess the inflammatory response in the spinal cord. Our results showed that Genistein administration suppressed the production of pro-inflammatory cytokines and alleviated gliosis in the spinal cord of SOD1-G93A mice. In addition, genistein administration induced autophagic processes and enhanced the viability of spinal motor neurons. As a result, genistein alleviated ALS-related symptoms and slightly prolonged the lifespan of SOD1-G93A mice. Taken together, our results indicate that genistein is neuroprotective in SOD1-G93A mice, suggesting genistein could be a promising treatment for human ALS. Graphical Abstract Genistein protects impariments in SOD1-G93A transgenic mouse model.

Effects of diet on adenosine monophosphate-activated protein kinase activity and disease progression in an amyotrophic lateral sclerosis model.

OBJECTIVES: To study the effects of diet on disease progression and activity levels of adenosine monophosphate-activated protein kinase (AMPK), and its downstream targets, in an amyotrophic lateral sclerosis (ALS) animal model. METHODS: AMPK activity was measured in cerebral cortex, spinal cord, cerebellum and hindlimb muscle tissue using immunohistochemistry in transgenic mice overexpressing human superoxide dismutase-1 (SOD1(G93A)) fed a high-fat (HFD), standard ad libitum (AL) or calorie-restricted (CR) diet; AMPK activity was also measured in wild-type (SOD1(WT)) mice. Activity of AMPK and phospho-AMPK, acetyl coenzyme-A carboxylase (ACC), phospho-ACC and heat shock protein-70 (Hsp70) were also measured using Western blot. Food intake and grip strength were recorded; body composition was analysed using dual energy X-ray absorptiometry. Motor neuron survival was observed using Nissl staining. RESULTS: AMPK activity increased and Hsp70 expression decreased in AL SOD1(G93A) mice compared with SOD1(WT) mice in spinal cord and hindlimb muscle. Compared with AL SOD1(G93A) mice, CR SOD1(G93A) mice showed increased AMPK activity, downregulated Hsp70 expression, reduced motor neuron survival in spinal cord and hindlimb muscle and reduced lifespan; HFD SOD1(G93A) mice showed opposite effects. CONCLUSIONS: In this mouse model, increased AMPK activity seems to play a negative role in motor neuron survival, possibly through a novel mechanism involving Hsp70 downregulation. These changes can be modified by diet. Inhibition of AMPK may provide a therapeutic strategy for ALS.

Adenosine monophosphate-activated protein kinase activation enhances embryonic neural stem cell apoptosis in a mouse model of amyotrophic lateral sclerosis.

Alterations in embryonic neural stem cells play crucial roles in the pathogenesis of amyotrophic lateral sclerosis. We hypothesized that embryonic neural stem cells from SOD1(G93A) individuals might be more susceptible to oxidative injury, resulting in a propensity for neurodegeneration at later stages. In this study, embryonic neural stem cells obtained from human superoxide dismutase 1 mutant (SOD1(G93A)) and wild-type (SOD1(WT)) mouse models were exposed to H2O2. We assayed cell viability with mitochondrial succinic dehydrogenase colorimetric reagent, and measured cell apoptosis by flow cytometry. Moreover, we evaluated the expression of the adenosine monophosphate-activated protein kinase (AMPK) α-subunit, paired box 3 (Pax3) protein, and p53 in western blot analyses. Compared with SOD1(WT) cells, SOD1(G93A) embryonic neural stem cells were more likely to undergo H2O2-induced apoptosis. Phosphorylation of AMPKα in SOD1(G93A) cells was higher than that in SOD1(WT) cells. Pax3 expression was inversely correlated with the phosphorylation levels of AMPKα. p53 protein levels were also correlated with AMPKα phosphorylation levels. Compound C, an inhibitor of AMPKα, attenuated the effects of H2O2. These results suggest that embryonic neural stem cells from SOD1(G93A) mice are more susceptible to apoptosis in the presence of oxidative stress compared with those from wild-type controls, and the effects are mainly mediated by Pax3 and p53 in the AMPKα pathway.

[Comparison of Cj1136, Cj1138 and Cj1139 genes among Campylobacter jejuni strains].

OBJECTIVE: By sequenceing the Cj1136, Cj1138 and Cj1139 gene of Campylobacter jejuni (C. jejuni) strains associated with Guillain-Barré Syndrome (GBS), features of Cj1136, Cj1138 and Cj1139 gene were studied. Results were compared with the C. jejuni strain NCTC11168, to find the mutations in sequence of C. jejuni which inducing GBS and their polygenetic relationship was analyzed. METHODS: Three GBS-associated C. jejuni strains were isolated from stools of GBS patients from Hebei province who had been diagnosed as clinical AMAN pattern and electrophysiological tests were performed. After distilling and sequencing Cj1136, Cj1138 and Cj1139 genes, results were spliced and assembled into a complete sequence by the terminals overlapped with each other. Sequences of Cj1136, Cj1138 and Cj1139 genes were compared with NCTC11168, to find the mutations and gene feature. RESULTS: The Cj1136, Cj1138 and Cj1139 gene of the three GBS- associated C. jejuni strains were composed by 1173 base pairs, 1170 base pairs, 912 base pairs respectively. The alignment with the related sequence of NCTC11168 showed that there were two same mutations in the Cj1138 gene of the three C. jejuni stains. Data from phylogenetic analysis demonstrated that the three C. jejuni strains were genetically closed to NCTC11168, with the biggest phylogenetic distance between the three of them as 2.1%. CONCLUSION: When compared with NCTC11168 the Cj1138 gene of the three GBS-associated C. jejuni strains had the same mutations which might be related to the development of GBS. Relation between the variation and GBS-pathogenesis remained to be confirmed. The mutations found in the three C. jejuni strains established the foundation for exploring the biological characteristics of GBS-associated C. jejuni strains and demonstrated that the GBSassociated C. jejuni strains of Hebei province having its regional features.