APOE and immunity: Research highlights Kloske, Courtney M.; Barnum, Christopher J.; Batista, Andre F. ...
Alzheimer's & dementia,
June 2023, Letnik:
19, Številka:
6
Journal Article
Recenzirano
Odprti dostop
INTRODUCTION
At the Alzheimer's Association's APOE and Immunity virtual conference, held in October 2021, leading neuroscience experts shared recent research advances on and inspiring insights into ...the various roles that both the apolipoprotein E gene (APOE) and facets of immunity play in neurodegenerative diseases, including Alzheimer's disease and other dementias.
METHODS
The meeting brought together more than 1200 registered attendees from 62 different countries, representing the realms of academia and industry.
RESULTS
During the 4‐day meeting, presenters illuminated aspects of the cross‐talk between APOE and immunity, with a focus on the roles of microglia, triggering receptor expressed on myeloid cells 2 (TREM2), and components of inflammation (e.g., tumor necrosis factor α TNFα).
DISCUSSION
This manuscript emphasizes the importance of diversity in current and future research and presents an integrated view of innate immune functions in Alzheimer's disease as well as related promising directions in drug development.
Metagenomic sequencing is a promising approach for identifying and characterizing organisms and their functional characteristics in complex, polymicrobial infections, such as airway infections in ...people with cystic fibrosis. These analyses are often hampered, however, by overwhelming quantities of human DNA, yielding only a small proportion of microbial reads for analysis. In addition, many abundant microbes in respiratory samples can produce large quantities of extracellular bacterial DNA originating either from biofilms or dead cells. We describe a method for simultaneously depleting DNA from intact human cells and extracellular DNA (human and bacterial) in sputum, using selective lysis of eukaryotic cells and endonuclease digestion. We show that this method increases microbial sequencing depth and, consequently, both the number of taxa detected and coverage of individual genes such as those involved in antibiotic resistance. This finding underscores the substantial impact of DNA from sources other than live bacteria in microbiological analyses of complex, chronic infection specimens.
Display omitted
•Human and extracellular bacterial DNA can bias metagenomic sequencing•Hypotonic lysis, endonuclease digestion limit human and extracellular bacterial DNA•Reducing extracellular DNA optimizes metagenomic sequencing of viable bacterial cells•Increased microbial sequencing coverage improves detection of important genes
Nelson et al. describe a method for reducing both human cellular DNA and extracellular DNA (human and bacterial) in a complex respiratory sample using hypotonic lysis and endonuclease digestion. This method increases effective microbial sequencing depth and minimizes bias introduced into subsequent phylogenetic analysis by bacterial extracellular DNA.
The in vivo application of cytolytic peptides for cancer therapeutics is hampered by toxicity, nonspecificity, and degradation. We previously developed a specific strategy to synthesize a nanoscale ...delivery vehicle for cytolytic peptides by incorporating the nonspecific amphipathic cytolytic peptide melittin into the outer lipid monolayer of a perfluorocarbon nanoparticle. Here, we have demonstrated that the favorable pharmacokinetics of this nanocarrier allows accumulation of melittin in murine tumors in vivo and a dramatic reduction in tumor growth without any apparent signs of toxicity. Furthermore, direct assays demonstrated that molecularly targeted nanocarriers selectively delivered melittin to multiple tumor targets, including endothelial and cancer cells, through a hemifusion mechanism. In cells, this hemifusion and transfer process did not disrupt the surface membrane but did trigger apoptosis and in animals caused regression of precancerous dysplastic lesions. Collectively, these data suggest that the ability to restrain the wide-spectrum lytic potential of a potent cytolytic peptide in a nanovehicle, combined with the flexibility of passive or active molecular targeting, represents an innovative molecular design for chemotherapy with broad-spectrum cytolytic peptides for the treatment of cancer at multiple stages.
Summary
Objective
Epilepsy is a disorder of aberrant cortical networks. Researchers have proposed that characterizing presurgical network connectivity may improve the surgical management of ...intractable seizures, but few studies have rigorously examined the relationship between network activity and surgical outcome. In this study, we assessed whether local and global measures of network activity differentiated patients with favorable (seizure‐free) versus unfavorable (seizure‐persistent) surgical outcomes.
Methods
Seventeen pediatric intracranial electroencephalography (IEEG) patients were retrospectively examined. For each patient, 1,200 random interictal epochs of 1‐s duration were analyzed. Functional connectivity networks were constructed using an amplitude‐based correlation technique (Spearman correlation). Global network synchrony was computed as the average pairwise connectivity strength. Local signal heterogeneity was defined for each channel as the variability of EEG amplitude (root mean square) and absolute delta power (μV2/Hz) across epochs. A support vector machine learning algorithm used global and local measures to classify patients by surgical outcome. Classification was assessed using the Leave‐One‐Out (LOO) permutation test.
Results
Global synchrony was increased in the seizure‐persistent group compared to seizure‐free patients (Student's t‐test, p = 0.006). Seizure‐onset zone (SOZ) electrodes exhibited increased signal heterogeneity compared to non‐SOZ electrodes, primarily in seizure‐persistent patients. Global synchrony and local heterogeneity measures were used to accurately classify 16 (94.1%) of 17 patients by surgical outcome (LOO test, iterations = 10,000, p < 0.001).
Significance
Measures of global network synchrony and local signal heterogeneity represent promising biomarkers for assessing patient candidacy in pediatric epilepsy surgery.
Alzheimer's disease is characterized by the misfolding and self-assembly of the amyloidogenic protein amyloid-β (Aβ). The aggregation of Aβ leads to diverse oligomeric states, each of which may be ...potential targets for intervention. Obtaining insight into Aβ oligomers at the atomic level has been a major challenge to most techniques. Here, we use magic angle spinning recoupling (1)H-(1)H NMR experiments to overcome many of these limitations. Using (1)H-(1)H dipolar couplings as a NMR spectral filter to remove both high and low molecular weight species, we provide atomic-level characterization of a non-fibrillar aggregation product of the Aβ1-40 peptide using non-frozen samples without isotopic labeling. Importantly, this spectral filter allows the detection of the specific oligomer signal without a separate purification procedure. In comparison to other solid-state NMR techniques, the experiment is extraordinarily selective and sensitive. A resolved 2D spectra could be acquired of a small population of oligomers (6 micrograms, 7% of the total) amongst a much larger population of monomers and fibers (93% of the total). By coupling real-time (1)H-(1)H NMR experiments with other biophysical measurements, we show that a stable, primarily disordered Aβ1-40 oligomer 5-15 nm in diameter can form and coexist in parallel with the well-known cross-β-sheet fibrils.
XIAP (X-linked inhibitor of apoptosis) deficiency is a rare inborn error of immunity. XIAP deficiency causes hyperinflammatory disease manifestations due to dysregulated TNF (tumor necrosis ...factor)-receptor signaling and NLRP3 (NOD- nucleotide-binding oligomerization domain, LRR- leucine-rich repeat and pyrin domain-containing protein 3) inflammasome function. Safe and effective long-term treatments are needed and are especially important to help prevent the need for high-risk allogeneic hematopoietic cell transplantation. Here we evaluated inflammasome inhibitors as potential therapeutics with a focus on the natural flavonoid antioxidant quercetin. Bone marrow (BM)-derived macrophages were derived from XIAP-deficient or wild-type (WT) mice. Human monocytes were obtained from control or XIAP-deficient patients. Cells were stimulated with TLR (Toll-like receptor) agonists or TNF-α ± inhibitors or quercetin. For in vivo lipopolysaccharide (LPS) challenge experiments, XIAP-deficient or WT mice were fed mouse chow ± supplemental quercetin (50 mg/kg per day exposure) for 7 days followed by a challenge with 10 ng/kg LPS. IL-1β (interleukin-1β) and IL-18 were measured by ELISA (enzyme-linked immunosorbent assay). In murine studies, quercetin prevented IL-1β secretion from XIAP knockout cells following TLR agonists or TNF-α stimulation (P < .05) and strongly reduced constitutive production of IL-18 by both WT and XIAP-deficient cells (P < .05). At 4 hours after in vivo LPS challenge, blood levels of IL-1β and IL-18 were significantly decreased in mice that had received quercetin-supplemented chow (P < .05). In experiments using human cells, quercetin greatly reduced IL-1β secretion by monocytes following TNF-α stimulation (P < .05). Our data suggest that quercetin may be an effective natural therapeutic for the prevention of XIAP deficiency-associated hyperinflammation. Clinical trials, including careful pharmacokinetic and pharmacodynamic studies to ensure that effective levels of quercetin can be obtained, are warranted.
Coronavirus disease (COVID-19) is a global threat to health. Its inflammatory characteristics are incompletely understood.
To define the cytokine profile of COVID-19 and to identify evidence of ...immunometabolic alterations in those with severe illness.
Levels of IL-1β, IL-6, IL-8, IL-10, and sTNFR1 (soluble tumor necrosis factor receptor 1) were assessed in plasma from healthy volunteers, hospitalized but stable patients with COVID-19 (COVID
patients), patients with COVID-19 requiring ICU admission (COVID
patients), and patients with severe community-acquired pneumonia requiring ICU support (CAP
patients). Immunometabolic markers were measured in circulating neutrophils from patients with severe COVID-19. The acute phase response of AAT (alpha-1 antitrypsin) to COVID-19 was also evaluated.
IL-1β, IL-6, IL-8, and sTNFR1 were all increased in patients with COVID-19. COVID
patients could be clearly differentiated from COVID
patients, and demonstrated higher levels of IL-1β, IL-6, and sTNFR1 but lower IL-10 than CAP
patients. COVID-19 neutrophils displayed altered immunometabolism, with increased cytosolic PKM2 (pyruvate kinase M2), phosphorylated PKM2, HIF-1α (hypoxia-inducible factor-1α), and lactate. The production and sialylation of AAT increased in COVID-19, but this antiinflammatory response was overwhelmed in severe illness, with the IL-6:AAT ratio markedly higher in patients requiring ICU admission (
< 0.0001). In critically unwell patients with COVID-19, increases in IL-6:AAT predicted prolonged ICU stay and mortality, whereas improvement in IL-6:AAT was associated with clinical resolution (
< 0.0001).
The COVID-19 cytokinemia is distinct from that of other types of pneumonia, leading to organ failure and ICU need. Neutrophils undergo immunometabolic reprogramming in severe COVID-19 illness. Cytokine ratios may predict outcomes in this population.
Whereas most nontyphoidal Salmonella (NTS) are associated with gastroenteritis, there has been a dramatic increase in reports of NTS-associated invasive disease in sub-Saharan Africa. Salmonella ...enterica serovar Typhimurium isolates are responsible for a significant proportion of the reported invasive NTS in this region. Multilocus sequence analysis of invasive S. Typhimurium from Malawi and Kenya identified a dominant type, designated ST313, which currently is rarely reported outside of Africa. Whole-genome sequencing of a multiple drug resistant (MDR) ST313 NTS isolate, D23580, identified a distinct prophage repertoire and a composite genetic element encoding MDR genes located on a virulence-associated plasmid. Further, there was evidence of genome degradation, including pseudogene formation and chromosomal deletions, when compared with other S. Typhimurium genome sequences. Some of this genome degradation involved genes previously implicated in virulence of S. Typhimurium or genes for which the orthologs in S. Typhi are either pseudogenes or are absent. Genome analysis of other epidemic ST313 isolates from Malawi and Kenya provided evidence for microevolution and clonal replacement in the field.
PDF
