HTCC: Broad Range Inhibitor of Coronavirus Entry

Abstract

To date, six human coronaviruses have been known, all of which are associated with respiratory infections in humans. With the exception of the highly pathogenic SARS and MERS coronaviruses, human coronaviruses (HCoV-NL63, HCoV-OC43, HCoV-229E, and HCoV-HKU1) circulate worldwide and typically cause the common cold. In most cases, infection with these viruses does not lead to severe disease, although acute infections in infants, the elderly, and immunocompromised patients may progress to severe disease requiring hospitalization. Importantly, no drugs against human coronaviruses exist, and only supportive therapy is available. Previously, we proposed the cationically modified chitosan, N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride (HTCC), and its hydrophobically-modified derivative (HM-HTCC) as potent inhibitors of the coronavirus HCoV-NL63. Here, we show that HTCC inhibits interaction of a virus with its receptor and thus blocks the entry. Further, we demonstrate that HTCC polymers with different degrees of substitution act as effective inhibitors of all low-pathogenic human coronaviruses.

Biopolymeric nano/microspheres for selective and reversible adsorption of coronaviruses

“…The decrease in the number of HCoV-NL63 RNA copies after addition of 10 mg/500 μl CHIT-NS/MS was not statistically significant indicating that the CHIT-NS/MS surface has not high enough charge density to bind HCoV-NL63. Observed results are consistent with data reported previously [32].…”

“…We previously found that the water-soluble HTCC is a strong inhibitor of HCoV-NL63 and mouse hepatitis virus (MHV) [31], however, it is a very weak inhibitor of human coronavirus HCoV-OC43 [32]. To find out if the virus inhibitory activity of HTCC is correlated with its adsorptive properties, we studied the specificity of the adsorption of these coronavirus strains by H-HTCC-NS/MS.…”

“…The polymer showed high specificity towards coronaviruses, as it inhibited replication of coronaviruses that belong to two separate genera: HCoV-NL63 (alphacoronavirus) and the mouse hepatitis virus (MHV; betacoronavirus). Further study proved that fine-tuning of HTCC substitution degree enables it to inhibit replication of all human coronaviruses [32].…”

APOBEC3-mediated restriction of RNA virus replication

“…RNA yields were assessed using real-time PCR (7500 Fast Real-Time PCR; Life Technologies, Poland). HCoV-NL63 cDNA was amplified in a reaction mixture containing 1 × TaqMan Universal PCR Master Mix (Thermo Fisher Scientific, Poland), in the presence of FAM/TAMRA (6-carboxyfluorescein/6carboxytetramethylrhodamine) probe (100 nM specific) and primers (450 nM each) 47 . Reaction was carried out according to the scheme: 2 min at 50 °C and 10 min at 92 °C, followed by 40 cycles of 15 sec at 92 °C and 1 min at 60 °C.…”

“…Reaction was carried out according to the scheme: 10 min at 50 °C and 5 min at 95 °C, followed by 40 cycles of 30 sec at 95 °C, 30 sec at 56 °C and 45 sec at 75 °C. In order to assess the copy number for each gene, DNA standards were prepared, as described before 47 .…”