Alzheimer's disease associated isoforms of human CD33 distinctively modulate microglial cell responses in 5XFAD mice.

Microglia play diverse pathophysiological roles in Alzheimer's disease (AD), with genetic susceptibility factors skewing microglial cell function to influence AD risk. CD33 is an immunomodulatory receptor associated with AD susceptibility through a single nucleotide polymorphism that modulates mRNA splicing, skewing protein expression from a long protein isoform (CD33M) to a short isoform (CD33m). Understanding how human CD33 isoforms differentially impact microglial cell function in vivo has been challenging due to functional divergence of CD33 between mice and humans.

Molecular Insights into O-Linked Sialoglycans Recognition by the Siglec-Like SLBR-N (SLBR) of .

is a Gram-positive bacterial species that typically colonizes the human oral cavity, but can also cause local or systemic diseases. Serine-rich repeat (SRR) glycoproteins exposed on the bacterial surface bind to sialylated glycans on human salivary, plasma, and platelet glycoproteins, which may contribute to oral colonization as well as endocardial infections. Despite a conserved overall domain organization of SRR adhesins, the Siglec-like binding regions (SLBRs) are highly variable, affecting the recognition of a wide range of sialoglycans.

Disrupting Protein Expression with Double-Clicked sgRNA-Cas9 Complexes: A Modular Approach to CRISPR Gene Editing.

CRISPR-Cas9 is currently the most versatile technique to perform gene editing in living organisms. In this approach, the Cas9 endonuclease is guided toward its DNA target sequence by the guide RNA (gRNA). Chemical synthesis of a functional single gRNA (sgRNA) is nontrivial because of the length of the RNA strand.

CRISPR-Click Enables Dual-Gene Editing with Modular Synthetic sgRNAs.

Gene-editing systems such as CRISPR-Cas9 readily enable individual gene phenotypes to be studied through loss of function. However, in certain instances, gene compensation can obfuscate the results of these studies, necessitating the editing of multiple genes to properly identify biological pathways and protein function. Performing multiple genetic modifications in cells remains difficult due to the requirement for multiple rounds of gene editing.

Carbohydrate Sulfation As a Mechanism for Fine-Tuning Siglec Ligands.

The immunomodulatory family of Siglecs recognizes sialic acid-containing glycans as "", which is exploited in cancer for immune evasion. The biochemical nature of Siglec ligands remains incompletely understood, with emerging evidence suggesting the importance of carbohydrate sulfation. Here, we investigate how specific sulfate modifications affect Siglec ligands by overexpressing eight carbohydrate sulfotransferases (CHSTs) in five cell lines.

Increasing phagocytosis of microglia by targeting CD33 with liposomes displaying glycan ligands.

CD33 is an immunomodulatory receptor expressed by microglia and genetically linked to Alzheimer's disease (AD) susceptibility. While antibodies targeting CD33 have entered clinical trials to treat neurodegeneration, it is unknown whether the glycan-binding properties of CD33 can be exploited to modulate microglia. Here, we use liposomes that multivalently display glycan ligands of CD33 (CD33L liposomes) to engage CD33.

Mutations in Peroxisomal Biogenesis Disorders: An Usher Syndrome Mimic.

Purpose: Peroxisomal biogenesis disorders (PBDs) represent a spectrum of conditions that result in vision loss, sensorineural hearing loss, neurologic dysfunction, and other abnormalities resulting from aberrant peroxisomal function caused by mutations in genes. With no treatments currently available, we sought to investigate the disease mechanism in a patient with a PBD caused by defects in and to probe whether overexpression of could restore peroxisome function and potentially offer therapeutic benefit.

Design: Laboratory-based study.

The CD33 short isoform is a gain-of-function variant that enhances Aβ phagocytosis in microglia.

Background: CD33 is genetically linked to Alzheimer's disease (AD) susceptibility through differential expression of isoforms in microglia. The role of the human CD33 short isoform (hCD33m), preferentially encoded by an AD-protective CD33 allele (rs12459419T), is unknown. Here, we test whether hCD33m represents a loss-of-function or gain-of-function variant.

A versatile soluble siglec scaffold for sensitive and quantitative detection of glycan ligands.

Sialic acid-binding immunoglobulin-type lectins (Siglecs) are immunomodulatory receptors that are regulated by their glycan ligands. The connections between Siglecs and human disease motivate improved methods to detect Siglec ligands. Here, we describe a new versatile set of Siglec-Fc proteins for glycan ligand detection.

Erratum: Author Correction: Repression of phagocytosis by human CD33 is not conserved with mouse CD33.

[This corrects the article DOI: 10.1038/s42003-019-0698-6.].

Repression of phagocytosis by human CD33 is not conserved with mouse CD33.

CD33 is an immunomodulatory receptor linked to Alzheimer's disease (AD) susceptibility via regulation of phagocytosis in microglia. Divergent features between human CD33 (hCD33) and murine CD33 (mCD33) include a unique transmembrane lysine in mCD33 and cytoplasmic tyrosine in hCD33. The functional consequences of these differences in restraining phagocytosis remains poorly understood.

Responses of human mast cells and epithelial cells following exposure to influenza A virus.

As a part of innate immune defense, the role of mast cells during viral replication has been incompletely understood. In this study, we characterized and compared the responses of the human mast cell line, LAD2, and human lung epithelial cell line, Calu-3, against three influenza A virus strains; A/PR/8/34 (H1N1), A/WS/33 (H1N1) and A/HK/8/68 (H3N2). We found that there were strain-dependent mast cell responses, and different profiles of cytokine, chemokine and antiviral gene expression between the two cell types.

Choroideremia.

Purpose Of Review: Although much has been written to define the phenotype and genotype of choroideremia (CHM), research continues to provide new insights that serve to better understand its pathogenesis and the directions for potential experimental therapies.

Recent Findings: We would like to highlight new findings, expanding the type of disease-causing mutations to include mutations in the CHM promoter that will dramatically influence gene expression. Information derived from careful phenotyping of patients points increasingly to the central role of the retinal pigment epithelium as the key cell layer affected in the degenerative process.

A novel biomarker associated with distress in humans: calcium-binding protein, spermatid-specific 1 (CABS1).

Calcium-binding protein spermatid-specific 1 (CABS1) is expressed in the human submandibular gland and has an anti-inflammatory motif similar to that in submandibular rat 1 in rats. Here, we investigate CABS1 in human saliva and its association with psychological and physiological distress and inflammation in humans. Volunteers participated across three studies: ) weekly baseline measures; ) a psychosocial speech and mental arithmetic stressor under evaluative threat; and ) during academic exam stress.

Calcium-binding protein, spermatid-specific 1 is expressed in human salivary glands and contains an anti-inflammatory motif.

Salivary glands are involved in the production and exocrine and endocrine secretion of biologically active proteins, polypeptides, and hormones involved in growth and differentiation, homeostasis, and digestion. We have previously studied the prohormone submandibular rat 1 (SMR1), product of the Vcsa1 gene, which is highly expressed in the testes and salivary glands of rats, and can be cleaved to produce polypeptides with analgesic, erectile function, and anti-inflammatory activities. Humans lack the Vcsa1 gene, but homologous sequences and functions for analgesia and erectile function exist in the human genes Prol1, SMR3a, and SMR3b located on the human chromosomal region close to where Vcsa1 lies in the rat.

Measurement of nitric oxide in mast cells with the fluorescent indicator DAF-FM diacetate.

The production of nitric oxide in mast cells has been difficult to measure due to the low amounts made by mast cells, as well as limitations in the specificity and sensitivity of the assays available. We present here a sensitive and specific 96-well plate-based method to directly measure NO using the cell-permeable fluorescent compound DAF-FM diacetate.

Limited replication of influenza A virus in human mast cells.

Mast cells are important in innate immunity and protective against certain bacterial infections. However, there is limited evidence that mast cells respond to viruses. As mast cells are abundant in mucosal tissues of the lung, they are in a prime location to detect and respond to influenza virus.

Autonomic regulation of anti-inflammatory activities from salivary glands.

The cervical sympathetic nerves which innervate the medial basal hypothalamus-hypophyseal complex, primary and secondary lymph organs, and numerous glands, such as the pineal, thyroid, parathyroid and salivary glands form a relevant neuroimmunoendocrine structure that is involved in the regulation of systemic homeostasis. The superior cervical ganglia and the submandibular glands form a 'neuroendocrine axis' called the cervical sympathetic trunk submandibular gland (CST-SMG) axis. The identification of this axis usurps the traditional view of salivary glands as accessory digestive structures and reinforces the view that they are important sources of systemically active immunoregulatory and anti-inflammatory factors whose release is intimately controlled by the autonomic nervous system, and in particular the sympathetic branch.

Expression of nitric oxide synthases in leukocytes in nasal polyps.

Background: Nitric oxide (NO) has various roles in airway physiology and pathophysiology. Monitoring exhaled NO levels is increasingly common to measure airways inflammation and inhaled NO studied for its therapeutic value in premature infants and adult respiratory distress syndrome. NO is produced by 3 isoforms of NO synthase (NOS1, 2, 3), and each can play distinct and perhaps overlapping roles in the airways.

Regulation of inflammation by Rac2 in immune complex-mediated acute lung injury.

Acute lung injury (ALI) is an inflammatory disorder associated with recruitment and activation of neutrophils in lungs. Rac2, a member of the Rho GTPase subfamily, is an essential regulator of neutrophil degranulation, superoxide release, and chemotaxis. Here, we hypothesized that Rac2 is important in mediating lung injury.