Exploring the dual effect of novel 1,4-diarylpyranopyrazoles as antiviral and anti-inflammatory for the management of SARS-CoV-2 and associated inflammatory symptoms.

COVID-19 and associated substantial inflammations continue to threaten humankind triggering death worldwide. So, the development of new effective antiviral and anti-inflammatory medications is a major scientific goal. Pyranopyrazoles have occupied a crucial position in medicinal chemistry because of their biological importance. Here, we report the design and synthesis of a series of sixteen pyranopyrazole derivatives substituted with two aryl groups at N-1 and C-4. The designed compounds are suggested to show dual activity to combat the emerging Coronaviruses and associated substantial inflammations. All compounds were evaluated for their in vitro antiviral activity and cytotoxicity against SARS-CoV infected Vero cells. As well, the in vitro assay of all derivatives against the SARS-CoV Mpro target was performed. Results revealed the potential of three pyranopyrazoles (22, 27, and 31) to potently inhibit the viral main protease with IC50 values of 2.01, 1.83, and 4.60 µM respectively compared with 12.85 and 82.17 µM for GC-376 and lopinavir. Additionally, in vivo anti-inflammatory testing for the most active compound 27 proved its ability to reduce levels of two cytokines (TNF-α and IL-6). Molecular docking and dynamics simulation revealed consistent results with the in vitro enzymatic assay and indicated the stability of the putative complex of 27 with SARS-CoV-2 Mpro. The assessment of metabolic stability and physicochemical properties of 27 have also been conducted. This investigation identified a set of metabolically stable pyranopyrazoles as effective anti-SARS-CoV-2 Mpro and suppressors of host cell cytokine release. We believe that the new compounds deserve further chemical optimization and evaluation for COVID-19 treatment.

Hepatoma-derived growth factor-related protein-3: a new neurotrophic and neurite outgrowth-promoting factor for cortical neurons.

Hepatoma-derived growth factor-related proteins (HRPs) make up a family of six members. Hepatoma-derived growth factor-related protein-3 (HRP-3) is the only family member whose expression is almost restricted to nervous tissue. Here we show that soluble HRP-3 acts as a novel neurotrophic factor for cultured primary cortical neurons. Antibody-mediated neutralization of HRP-3 function results in neuronal degeneration. In contrast, HRP-3 as the only addition to a culture medium not supporting neuronal survival rescues neurons to an extent comparable to the addition of FCS. Besides this neuroprotective capability, the protein exerts a neurite outgrowth-promoting effect when it is presented as a coated substrate but not as a soluble factor. This study points to an important role of HRP-3 during the development of the nervous system.

Hepatoma-derived growth factor-related protein-3 interacts with microtubules and promotes neurite outgrowth in mouse cortical neurons.

Hepatoma-derived growth factor-related proteins (HRP) comprise a family of 6 members, which the biological functions are still largely unclear. Here we show that during embryogenesis HRP-3 is strongly expressed in the developing nervous system. At early stages of development HRP-3 is located in the cytoplasm and neurites of cortical neurons. Upon maturation HRP-3 relocalizes continuously to the nuclei and in the majority of neurons of adult mice it is located exclusively in the nucleus. This redistribution from neurites to nuclei is also found in embryonic cortical neurons maturing in cell culture. We show that HRP-3 is necessary for proper neurite outgrowth in primary cortical neurons. To identify possible mechanisms of how HRP-3 modulate neuritogenesis we isolated HRP-3 interaction partners and demonstrate that it binds tubulin through the N-terminal so called HATH region, which is strongly conserved among members of the HRP family. It promotes tubulin polymerization, stabilizes and bundles microtubules. This activity depends on the extranuclear localization of HRP-3. HRP-3 thus could play an important role during neuronal development by its modulation of the neuronal cytoskeleton.

Expression of hepatoma-derived growth factor family members in the adult central nervous system.

BACKGROUND: Hepatoma-derived growth factor (HDGF) belongs to a polypeptide family containing five additional members called HDGF related proteins 1-4 (HRP-1 to -4) and Lens epithelial derived growth factor. Whereas some family members such as HDGF and HRP-2 are expressed in a wide range of tissues, the expression of others is very restricted. HRP-1 and -4 are only expressed in testis, HRP-3 only in the nervous system. Here we investigated the expression of HDGF, HRP-2 and HRP-3 in the central nervous system of adult rats on the cellular level by immunohistochemistry. In addition we performed Western blot analysis of various brain regions as well as neuronal and glial cell cultures. RESULTS: HDGF was rather evenly expressed throughout all brain regions tested with the lowest expression in the substantia nigra. HRP-2 was strongly expressed in the thalamus, prefrontal and parietal cortex, neurohypophysis, and the cerebellum, HRP-3 in the bulbus olfactorius, piriform cortex and amygdala complex. HDGF and HRP-2 were found to be expressed by neurons, astrocytes and oligodendrocytes. In contrast, strong expression of HRP-3 in the adult nervous system is restricted to neurons, except for very weak expression in oligodendrocytes in the brain stem. Although the majority of neurons are HRP-3 positive, some like cerebellar granule cells are negative. CONCLUSION: The coexpression of HDGF and HRP-2 in glia and neurons as well as the coexpression of all three proteins in many neurons suggests different functions of members of the HDGF protein family in cells of the central nervous system that might include proliferation as well as cell survival. In addition the restricted expression of HRP-3 point to a special function of this family member for neuronal cells.