Fig. 2

Inhibition of HDAC6 resulted in reduction of SARS CoV-2 replication. A A549 cells were either transfected with shHDAC6 or pcDNA-HDAC6-FLAG followed by SARS-CoV-2 infection (at a MOI = 1). Total RNA was isolated after 24 h of infection followed by qRT-PCR using SARS-CoV-2 orf1a, hdac6 and gapdh-specific primers. Data represent means ± SD of three independent experiments. ***p ≤ .001, unpaired t-test and **p ≤ .01, unpaired t-test. B Protein was extracted from SARS-CoV-2 infected cells at 24 hpi (MOI = 1) ectopically expressing shHDAC6 or pcDNA-HDAC6-FLAG. S, NSP13 and HDAC6 expression levels were analysed via western blotting. C SARS-CoV-2 infected (24 hpi) A549 cells were treated with increasing doses of tubacin (0–2.5 μM). Cellular extracts were subjected to immunoblot to analyse levels of S and NSP13. GAPDH was used as internal loading control. D Total RNA was isolated from tubacin treated SARS-CoV-2 infected cells (MOI = 1) at 24 hpi followed by qRT-PCR using SARS-CoV-2 orf1a and gapdh specific primers. Data represent means ± SD of three independent experiments. ***p ≤ .001, unpaired t-test and **p ≤ .01, unpaired t-test. E A549 cells were either transfected with empty vector or pcDNA-HDAC6-FLAG or pcDNA-HDAC6.DC-FLAG followed by SARS-CoV-2 infection (at a MOI = 0.5). Total RNA was isolated after 24 h of infection followed by qRT-PCR using SARS-CoV-2 orf1a, hdac6 and gapdh-specific primers. Data represent means ± SD of three independent experiments. ***p ≤ 0.001, unpaired t-test, *p ≤ 0.1, unpaired t-test and ns = not significant, unpaired t-test. F A549 cells were infected with SARS-CoV-2 (MOI = 1) either in presence or absence of tubacin (1–2.5 μM) for 24, 48 and 72 h followed by plaque assay. Viral titers were measured as plaque forming units [log (pfu/ml)]. Data represent means ± SD of three independent experiments. **p ≤ .01,multiple t-tests,***p ≤ .001, multiple t-tests and ns = not significant, multiple t-tests. G A549 cells were either transfected with empty vector or shHDAC6 or pcDNA-HDAC6-FLAG or pcDNA-HDAC6.DC-FLAG followed by SARS-CoV-2 infection (at a MOI = 0.5) for 24, 48 and 72 h followed by plaque assay. Viral titers were measured as plaque forming units [log (pfu/ml)]. Data represent means ± SD of three independent experiments. ***p ≤ .001, multiple t-tests, *p ≤ 0.05,  multiple t-tests and ns = not significant, multiple t-tests