Enoxaparin and Pentosan Polysulfate Bind to the SARS-CoV-2 Spike Protein and Human ACE2 Receptor, Inhibiting Vero Cell Infection

As with many other pathogens, SARS-CoV-2 cell infection is strongly dependent on the interaction of the virus-surface Spike protein with the glycosaminoglycans of target cells. The SARS-CoV-2 Spike glycoprotein was previously shown to interact with cell-surface-exposed heparan sulfate and heparin in vitro. With the aim of using Enoxaparin as a treatment for COVID-19 patients and as prophylaxis to prevent interpersonal viral transmission, we investigated GAG binding to the Spike full-length protein, as well as to its receptor binding domain (RBD) in solution by isothermal fluorescence titration. We found that Enoxaparin bound to both protein variants with similar affinities, compared to the natural GAG ligand heparan sulfate (with Kd-values in the range of 600–680 nM). Using size-defined Enoxaparin fragments, we discovered the optimum binding for dp6 or dp8 for the full-length Spike protein, whereas the RBD did not exhibit a significant chain-length-dependent affinity for heparin oligosaccharides. The soluble ACE2 receptor was found to interact with unfractionated GAGs in the low µM Kd range, but with size-defined heparins with clearly sub-µM Kd-values. Interestingly, the structural heparin analogue, pentosan polysulfate (PPS), exhibited high binding affinities to both Spike variants as well as to the ACE2 receptor. In viral infection experiments, Enoxaparin and PPS both showed a strong inhibition of infection in a concentration range of 50–500 µg/mL. Both compounds were found to retain their inhibitory effects at 500 µg/mL in a natural biomatrix-like human sputum. Our data suggest the early topical treatment of SARS-CoV-2 infections with inhaled Enoxaparin; some clinical studies in this direction are already ongoing, and they further imply an oral or nasal prophylactic inactivation of the virus by Enoxaparin or PPS for the prevention of inter-personal viral transmission.

Pentosan polysulfate inhibits attachment and infection by SARS-CoV-2 in vitro: insights into structural requirements for binding.

Two years since the outbreak of the novel coronavirus SARS-CoV-2 pandemic, there remain few clinically effective drugs to complement vaccines. One is the anticoagulant, heparin, which in 2004 was found able to inhibit invasion of SARS CoV (CoV-1) and which has been employed during the current pandemic to prevent thromboembolic complications and moderate potentially damaging inflammation. Heparin has also been shown experimentally to inhibit SARS-CoV-2 attachment and infection in susceptible cells. At high therapeutic doses however, heparin increases the risk of bleeding and prolonged use can cause heparin-induced thrombocytopenia, a serious side-effect. One alternative, with structural similarities to heparin is the plant-derived, semi-synthetic polysaccharide, pentosan polysulfate (PPS). PPS is an established drug for the oral treatment of interstitial cystitis, is well-tolerated and exhibits weaker anticoagulant effects than heparin. In an established Vero cell model, PPS and its fractions of varying molecular weights, inhibited invasion by SARS-CoV-2. Intact PPS and its size-defined fractions were characterized by molecular weight distribution and chemical structure using NMR spectroscopy and LC-MS, then employed to explore the structural basis of interactions with SARS-CoV-2 spike protein receptor-binding domain (S1 RBD) and the inhibition of Vero cell invasion. PPS was as effective as unfractionated heparin, but more effective at inhibiting cell infection than low molecular weight heparin (on a weight/volume basis). Isothermal titration calorimetry and viral plaque-forming assays demonstrated size-dependent binding to S1 RBD and inhibition of Vero cell invasion, suggesting the potential application of PPS as a novel inhibitor of SARS-CoV-2 infection.

Treatment of cystoid macular oedema secondary to pentosan polysulfate maculopathy using anti-VEGF and intravitreal steroid injections

Background Pentosan polysulfate-related maculopathy is a recently described clinical entity, related to dose and long term use of this medication, and may progress despite drug cessation. Cystoid macular oedema (CMO) has been reported in some cases, but there are few reports of treatment outcomes in the literature. Aims We present the case of a 55 year old female, with CMO secondary to pentosan polysulfate maculopathy, that was responsive to treatment with both intravitreal anti-VEGF and steroid injections, stabilising vision over a four year follow up period. Conclusions This is the first report, to our knowledge, of CMO related to pentosan polysulfate maculopathy responding to intravitreal steroid injections, broadening the therapeutic options for preserving vision in these patients.

A Review on Protein Misfolding Diseases and therapeutics for preventing Diseases

Background: Protein misfolding sicknesses are the gathering of irresistible lethal neuro and non-neurodegenerative infections and in ebb and flow researchers and specialists accepted that unusual folding of protein is the essential or main key of such illnesses are Alzheimer's infections, Parkinson's diseases, Huntington's sickness, Creutzfeldt-Jakob infection, cystic fibrosis, Gaucher's infection and numerous other degenerative and neurodegenerative problems. The motive of this review article is to gave a detailed of the existing structural information for prion and prion protein and also we will trying to find out their preventing root causes with respect to structural information of prions within the context of what is known about the protein misfolding diseases. Objective: This article presents a brief overview of research on the use of these therapeutics for the treatment or improvement in prion diseases or protein misfolding. Material and Methods: This article begins with the brief introduction about protein misfolding diseases or infections and the therapeutic materials which are used in researches or explain this article (pentosan polysulfate, Quinacrine, Doxycycline, Chaperone based therapy, Resveratrol and curcumin) etc. Results and Conclusions: In this present context of protein misfolding/prion diseases diagonsis.Therapeutic approaches predicts that person infected with prion diseases prolongs the survival time of the patient and improvement in the conditions of the prion diseased infected patient which provides good result for future medicine development. Keywords: Amyloid, Beta-sheet, neurodegenerative, prion, protein misfolding, therapeutics etc

Pentosan polysulfate sodium prevents functional decline in chikungunya infected mice by modulating growth factor signalling and lymphocyte activation

Chikungunya virus (CHIKV) is an arthropod-borne virus that causes large outbreaks world-wide leaving millions of people with severe and debilitating arthritis. Interestingly, clinical presentation of CHIKV arthritides have many overlapping features with rheumatoid arthritis including cellular and cytokine pathways that lead to disease development and progression. Currently, there are no specific treatments or vaccines available to treat CHIKV infections therefore advocating the need for the development of novel therapeutic strategies to treat CHIKV rheumatic disease. Herein, we provide an in-depth analysis of an efficacious new treatment for CHIKV arthritis with a semi-synthetic sulphated polysaccharide, Pentosan Polysulfate Sodium (PPS). Mice treated with PPS showed significant functional improvement as measured by grip strength and a reduction in hind limb foot swelling. Histological analysis of the affected joint showed local inflammation was reduced as seen by a decreased number of infiltrating immune cells. Additionally, joint cartilage was protected as demonstrated by increased proteoglycan staining. Using a multiplex-immunoassay system, we also showed that at peak disease, PPS treatment led to a systemic reduction of the chemokines CXCL1, CCL2 (MCP-1), CCL7 (MCP-3) and CCL12 (MCP-5) which may be associated with the reduction in cellular infiltrates. Further characterisation of the local effect of PPS in its action to reduce joint and muscle inflammation was performed using NanoString™ technology. Results showed that PPS altered the local expression of key functional genes characterised for their involvement in growth factor signalling and lymphocyte activation. Overall, this study shows that PPS is a promising treatment for alphaviral arthritis by reducing inflammation and protecting joint integrity.