Screening And Pharmacodynamic Study Of Anti-Sporothrix Globosa Targeting AbaA

Sporotrichosis is a fungal disease caused by a complex of Sporothrix schenckii which causes chronic infection of the epidermis and subcutaneous tissue in humans and animals.The disease often presents as cutaneous,cutaneous fixed and cutaneous disseminated types.The infection appears to be ulcerated and nodular,and can be lifethreatening in severe cases.The Sporothrix schenckii complex contains seven genotypes of Sporothrix,of which Sporothrix schenckii,Sporothrix brasiliensis and Sporothrix globosa are the main pathogens.the Sporotrichosis has been reported in various cities in China,mainly in Northeast China.In the northeast of China,the main pathogenic genotype is Sporothrix globosa,however,this pathogenic genotype is the most understudied.To our understanding,there is few relevant literatures about its basic research and clinical research.In recent years,the problem of drug resistance in invasive fungal diseases has emerged,and drug-resistant strains also have emerged in the Sporotrichosis,so it is urgent to find new drug targets.Based on the above background,a new small molecule drug was screened for the new target of Sporothrix,and its efficacy was tested.The results are as follows:1.We used the Robetta server to predict the three-dimensional structure of AbaA,a key pathogenic protein of Sporothrix globosa,and found the DNA-binding domain of AbaA by bioinformatics analysis.The DNA-binding domain of the highest-quality three-dimensional structure in model was truncated for binding pocket prediction,and the predicted binding pocket was subjected to bulk molecular docking using Auto Dock Vina in an FDA-approved small molecule database,the results of docking were analyzed in terms of binding energy,price,pharmacodynamics and side effects.Four small molecule drugs,AS-1,AS-2,AS-3 and AS-4,were selected as candidate drugs.2.The results showed that AS-1 and AS-2 had no effect on the growth and phase transformation of S.globose.However,AS-3 and AS-4 significantly inhibited the growth and phase transformation of S.globosa.At the same time,in order to test their broad-spectrum antibacterial activity,we also tested the sensitivity of the narrow-sense Sporothrix schenckii to two small-molecule drugs,the results showed that AS-3 and AS-4 also inhibited the growth and transformation of the narrow sense Sporothrix schenckii.The growth curve also showed that the growth of Sporothrix globosa and Sporothrix schenckii were inhibited by the addition of two small-molecule drugs.Then,the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of AS-3 and AS-4 were measured on the Sporothrix globosa and Sporothrix schenckii.The results showed that the MIC and MBC of AS-3 against Sporothrix globosa were 25 μg/m L and 50 μg/m L,the MIC and MBC of AS-3 against Sporothrix schenckii were 6.25 μg/m L and 50 μg/m L.The MIC and MBC of AS-4 against Sporothrix globosa were 12.5 μg/m L and 25 μg/m L.The MIC and MBC of AS-4against Sporothrix schenckii were 6.25 μg/m L and 25 μg/m L.3.The efficacy of AS-3 and AS-4 in the treatment of sporotrichosis was verified at the animal level at animal level by modeling sporotrichosis in the abdomen of mice by intradermal injection of sporotrichosis spore suspension.After the model was established,the mice were treated by intragastric administration of two small molecules,use Itraconazole as a positive control.At the end of the treatment,HE staining was used to observe the inflammatory infiltration and granuloma in the skin lesions of mice.The results showed that compared with the control group,the inflammatory infiltration and granuloma in the treatment group and the positive control group were less,the granuloma width and inflammatory cell infiltration in the control group were different from those in the treatment group significantly.Taken together,we conclude that the small molecules AS-3 and AS-4 have the ability to inhibit Sporothrix globose,Sporothrix schenckii and treat Sporotrichosis in vitro and in vivo in mice,therefore,they has the potential to be developed as the Sporotrichosis drug.This study successfully screened out two new drugs targeting Sporothrix globose,Sporothrix schenckii and provided a new idea for developing other antifungal drugs.