REVIEW | doi:10.20944/preprints202310.1159.v1
Subject: Medicine And Pharmacology, Ophthalmology Keywords: Microglia; Macrophages; Macular Degeneration; Sialic Acid; SIGLECs; Nanoparticles; Glycosylation; Geographic Atrophy; PolySialic Acid.
Online: 18 October 2023 (17:17:25 CEST)
Age-related macular degeneration, a leading cause of visual loss and dysfunction in the devel-oped world, is a disease initiated by genetic polymorphisms that impairs negative regulation of complement. Proteomic investigation points to altered glycosylation and loss of SIGLEC medi-ated glyco-immune checkpoint parainflammatory homeostasis as a main determinant for the vi-sion impairing complications of macular degeneration. The effect of altered glycosylation on microglial maintained retinal para-inflammatory homeostasis and eventual recruitment and polarization of peripheral blood monocyte derived macrophages (PBMDM) into the retina can explain the phenotypic variability seen in this clinically heterogenous disease. Restoring gly-co-immune checkpoint control with a sialic acid mimetic nanoparticle targeting microgli-al/macrophage SIGLECs to regain retinal para inflammatory homeostasis is a promising thera-peutic that could halt the progression of and improve visual function in all stages of macular de-generation.
REVIEW | doi:10.20944/preprints202310.0001.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: sialic acid; sialylation; xeno-sialic acid; COVID-19; SARS-CoV-2
Online: 1 October 2023 (07:28:10 CEST)
The host glycosylation mechanism synthesizes the carbohydrates of glycoproteins of viral envelopes. Due to the loss of the Cytidine Monophospho-N-Acetylneuraminic Acid Hydroxylase gene by some mammalian species, including humans (negative-CMAH), Neu5Gc is no longer synthesized. Uptake of Neu5Gc by negative-CMAH species, through the intake of food products derived from positive-CMAH mammals, leads to incorporating Neu5Gc-glycans in the glycocalyx (xenosialylation). Neu5Gc, being a Mammalian-associated Carbohydrate Antigen (MCA), acts as a non-self-antigen, inducing an inflammatory reaction (Xenosialitis), and triggering the production of circulating antiNeu5Gc antibodies to attack/remove all incorporated Neu5Gc. In the state of Xenosialitis, the virus-neutralizing antibodies produced by a heavily xenosialylated patient following exposure to viral infection (including SarsCoV2) or anti SarsCoV2 vaccination cross-react against all incorporated non-self Neu5Gc-MCA glycans due to their resemblance with viral envelope antigens synthesized by the host glycosylation mechanism. In addition, the circulating anti-XeSias antibodies determine the massive removal of the circulating neutralizing FC-xeno-contaminated antibodies by the serum, living only the hyper-inflammatory agalattosylated antiviral IgG antibodies. Therefore, we hypothesize that the combination of antibody cross-reaction against non-self Neu5Gc-MCA glycans and the massive removal of the xeno-contaminated newly formed neutralizing antibodies in favor of hyper reactive antibodies, could be the cause of the massive inflammatory reaction (cytokine storm, coagulopathies, neuropathies) observed in Covid 19 patients or after anti-SarsCoV2 vaccination. Therefore, evaluating the serum anti-MCA antibodies titer, particularly anti-Neu5GC antibodies, could be a groundbreaking tool to timely identify patients at risk of developing severe complications in case of all viral infections, including SARS-CoV2 and repeated vaccinations.
REVIEW | doi:10.20944/preprints201901.0158.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: sialidase; sialic acid; sialoglycoprotease; pathogenicity; therapeutic target; siglec
Online: 16 January 2019 (08:49:16 CET)
Periodontitis is a chronic inflammatory disease affecting the tissues that surround and support the teeth. In the U. S., approximately 65 million people are affected by this condition. Its occurrence is also associated with many important systemic diseases such as cardiovascular disease, rheumatoid arthritis, and Alzheimer’s disease. Among the most important etiologies of periodontitis is Porphyromonas gingivalis, a keystone bacterial pathogen. Keystone pathogens can orchestrate inflammatory disease by remodeling a normally benign microbiota causing imbalance between normal and pathogenic microbiota (dysbiosis). The important characteristics of P. gingivalis causing dysbiosis are its virulence factors that cause effective subversion of host defenses to its advantage , allowing other pathogens to grow. However, the mechanisms involving these processes are poorly understood. However, various microbial strategies target host sialoglycoproteins for immune dysregulation. In addition, the enzymes that break down sialoglycoproteins/sialoglycans are the “sialoglycoproteases”, resulting in exposed terminal sialic acid. This process could lead to pathogen-toll like receptor (TLR) interactions mediated through sialic acid receptor–ligand mechanisms. By assessing the function of P. gingivalis sialoglycoproteases, could pave the way to designing carbohydrate analogues and sialic acid mimetics to serve as drug targets.
ARTICLE | doi:10.20944/preprints202105.0588.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: osteoarthritis; collagen-hydrolysate; sulfated N-acetyl glucosamine; sialic acids; eicosapentaenoic acid (EPA); MMP-3; ADAMTS-5
Online: 25 May 2021 (08:27:16 CEST)
The bioactivities of collagen-hydrolysates, sulfated glucosamine and a special fatty acid enriched dog-food were tested in a dog patient study as potential therapeutic treatment options in early osteoarthritis. Biophysical, biochemical, cell biological and molecular modeling methods support that these well-defined substances may act as effective nutraceuticals. Importantly, the applied collagen-hydrolysates as well as sulfated glucosamine residues from marine organisms were strongly supported by both an animal model and molecular modeling of intermolecular interactions. Molecular modeling of predicted interaction dynamics were evaluated for the receptor proteins MMP-3 and ADAMTS-5. These proteins play a prominent role in the maintenance of cartilage health as well as innate and adapted immunity. Nutraceuticals data were generated in a veterinary clinical study focusing on mobility and agility. Specifically, key clinical parameters were obtained from blood probes of German shepherd dogs with early osteoarthritis symptoms fed with collagen-hydrolysates or sulfated glucosamines. Collagen-hydrolysate, a chondroprotective food supplement was examined by high resolution NMR experiments. Molecular modeling simulations were used to further characterize the interaction potency of collagen-fragments and glucosamines with protein receptor structures. Potential beneficial effects of collagen-hydrolysates, sulfated glycans (i.e. sulfated glucosamine from crabs and mussels) and lipids, especially, eicosapentaenoic acid (extracted from fish oil) on biochemical and physiological processes are discussed here in the context of human and veterinary medicine.
REVIEW | doi:10.20944/preprints202303.0477.v3
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: H5N1; Influenza A; first-line immunity; interferon; mucosal antibodies; immune evasion; sialic acid receptor; natural lymphocytes; adaptive lymphocytes; monocytes; macrophages; cytokines
Online: 27 April 2023 (02:56:58 CEST)
The Influenza A Virus (IAV) represents an enveloped, positive-sense and single-stranded RNA-based virus that infects mammals mainly via the respiratory system, although other bodily systems are also infected and undergo various extents of inflammatory pathogenesis. There are two well-known strains of IAV that cause life-threatening disease in mammals; H1N1 and H5N1, and the first strain caused the 1918 IAV H1N1 pandemic that claimed between 30 and 50 million human lives. Due to the significant ability of IAV to evade important immune recognition, the virus was observed to favor the onset of secondary microbial infections (i.e. bacterial or fungal), as the overall performance of the immune system became transiently weakened during the viral infection. During the IAV H1N1 pandemic, many patients died as a result of bacterial pneumonia, as pathogenic bacteria, such as Streptococcus pneumoniae and Haemophilus influenzae, gained a wider opportunity to colonize and infect vital areas of the lower respiratory tract, and such a phenomenon led to the excessive, prophylactic usage of antibiotics due to the increased levels of panic, which in turn favored the natural selection of bacteria with genes that became resistant to such antibiotics. Antibiotics might be required for usage solely when bacteria are known to be colonizing vital areas of the human body, and this aspect is tricky, as colonization is asymptomatic and screening is consequently rare. Recently, new variants of the avian IAV H5N1 strain were transmitted from live, infected birds to mammals, including humans in some isolated cases, and given that there have already been several zoonotic spillover events overall since the beginning of 2023, we are rapidly approaching the time when a zoonotic spillover into humans will mark the first epidemic outbreak of the avian flu in humans. A lethality rate of 60% was projected by the World Health Organization, as the virus was shown to favor the development of life-threatening hyper-inflammatory responses at the levels of alveolar tissues constituted by Type II pneumocytes. There are hints that novel variants of H5N1 are capable of infecting the intestinal layer, as recently, two dolphins died as a result of ingesting infected birds within the area of the British Isles. IAV is known to suppress the production and transmission of Type I Interferons by expressing various non-structural proteins (NSPs), such as NSP1, which was found to be also packaged into exosomes and transmitted to neighboring uninfected cells, thereby preventing them from responding to the virus in the first place. A more pronounced rate of innate immune evasion would probably be observed in H5N1 IAV infection than in the infection caused by recent variants of H1N1 IAV. The H5N1 strain of IAV was also found to secrete a higher concentration of NSP1 than SARS-CoV-2, indicating the existence of an association to the greater mortality rate of H5N1 IAV infection. A direct, prophylactic stimulation of the interferon system using a reduced oral or nasal dosage of recombinant anti-inflammatory and anti-viral interferon glycoproteins may represent the most viable approach to prevent an emergence of a life-threatening H5N1 IAV pandemic. A similar non-invasive approach could be developed for an Marburg Virus (MARV) and a Nipah Virus (NiV) infection of humans, as risks of the emergence of a Marburg epidemic and also of a Nipah epidemic may be substantial at this stage as well. Clinical testing of clinical approaches as such could be of critical importance at the moment. Animals could also benefit from related clinical approaches. Somatic natural and adaptive lymphocytes treated with IFN I and III could also constitute a substantial approach of immunization and heavily favor an indefinite shift in the evolutionary battle between the host organism and microbes of public health concern.