Dry eye disease (DED) is a prevalent and intractable ocular disease induced by a variety of causes. Elevated sphingomyelin (SM) levels and pro-inflammatory cytokines were detected on the ocular surface of DED patients, particularly in the meibomian glands. Sphingomyelin synthase 2 (SMS2), one of the proteins involved in SM synthesis, would light a novel way of developing a DED therapy strategy. Herein, we report the design and optimization of a series of novel thiophene carboxamide derivatives to afford 14l with an improved highly potent inhibitory activity on SM synthesis (IC_{50, SMS2} = 28 nmol/L). Moreover, 14l exhibited a notable protective effect of anti-inflammation and anti-apoptosis on human corneal epithelial cells (HCEC) under TNF-α-hyperosmotic stress conditions in vitro, with an acceptable ocular specific distribution (corneas and meibomian glands) and pharmacokinetics (PK) profiles (t _{1/2, cornea} = 1.11 h; t _{1/2, meibomian glands} = 4.32 h) in rats. Furthermore, 14l alleviated the dry eye symptoms including corneal fluorescein staining scores and tear secretion in a dose-dependent manner in mice. Mechanically, 14l reduced the mRNA expression of Tnf-α, Il-1β and Mmp-9 in corneas, as well as the proportion of very long chain SM in meibomian glands. Our findings provide a new strategy for DED therapy based on selective SMS2 inhibitors.

Objective To investigate the genomic characteristics and virulence factors of emetic-type Bacillus cereus strains isolated from food in Hangzhou for better understanding their pathogenic potential. Methods Real-time PCR was performed to detect the ces gene cluster ( cereulide) in 132 Bacillus cereus strains isolated from food from 2015 to 2017. Genomes of cereulide-positive strains were sequenced using Illumina MiSeq sequencing platform. Genome annotation, virulence factor detection, comparative and evolu-tionary analysis were performed after the sequences of genomes were assembled. Results Twelve strains (9. 09％) carried the ces gene. Their genome sizes ranged from 5. 35 to 5. 75 Mb and GC contents from 35. 25 to 35. 43 mol％. All of them harbored the full cereulide biosynthesis gene cluster, nonhemolytic ente-rotoxin ( NHE)-encoding gene cluster ( nheA, nheB and nheC) and hemolysinⅢ( hlyⅢ) . The average nu-cleotide identity ( ANI ) between the 12 isolates and the reference strain NC7401 ( Accession number:AP007209) was over 99. 35％. Phylogenetic analysis demonstrated these strains were clustered into the same branch with local clinical isolates and the emetic-type Bacillus cereus strains of NC7401 and AH187. Con-clusions The genomic sequences of the emetic-type Bacillus cereus strains isolated from food in Hangzhou area were highly similar to that of the reference strain NC7401. Results of the genomic analysis suggested that these isolates carried many virulence factors that were related to pathogenicity.