Biology subjects

Pinilla, C.

Publications and source records attributed to Pinilla, C..

3 recordsLinked to original sources

bioRxiv2024

Structure-activity relationship of pyrrolidine pentamine derivatives as inhibitors of the aminoglycoside 6'-N-acetyltransferase type Ib

Resistance to amikacin and other major aminoglycosides is commonly due to enzymatic acetylation by aminoglycoside 6'-N -acetyltransferase type I enzyme, of which type Ib [AAC(6')-Ib] is the most widespread among Gram-negative pathogens. Finding enzymatic inhibitors could be an effective way to overcome resistance and extend the useful life of amikacin. Small molecules possess multiple properties that make them attractive compounds to be developed as drugs. Mixture-based combinatorial libraries and positional scanning strategy led to the identification of a chemical scaffold, pyrrolidine pentamine, that, when substituted with the appropriate functionalities at five locations (R1 - R5), inhibits AAC(6')-Ib-mediated inactivation of amikacin. Structure-activity relationship (SAR) studies showed that while truncations to the molecule result in loss of inhibitory activity, modifications of functionalities and stereochemistry have different effects on the inhibitory properties. In this study, we show that alterations at position R1 of the two most active compounds, 2700.001 and 2700.003, reduced inhibition levels, demonstrating the essential nature not only of the presence of an S -phenyl moiety at this location but also the distance to the scaffold. On the other hand, modifications on the R3, R4, and R5 positions have varied effects, demonstrating the potential for optimization. A correlation analysis between molecular docking values ({Delta}G) and the dose required for two-fold potentiation of compounds described in this and the previous studies showed a significant correlation between {Delta}G values and inhibitory activity. HighlightsO_LIAmikacin resistance in Gram-negatives is mostly caused by the AAC(6')-Ib enzyme C_LIO_LIAAC(6')-Ib has been identified in most Gram-negative pathogens C_LIO_LIInhibitors of AAC(6')-Ib could be used to treat resistant infections C_LIO_LICombinatorial libraries and positional scanning identified an inhibitor C_LIO_LIThe lead compound can be optimized by structure activity relationship studies C_LI

biochemistry↗

bioRxiv2024

Antigen-driven CD8+ T cell clonal expansion is a prominent feature of MASH in humans and mice.

Background and AimsChronic liver disease due to metabolic dysfunction-associated steatohepatitis (MASH) is a rapidly increasing global epidemic. MASH progression is a consequence of the complex interplay between inflammatory insults and dysregulated hepatic immune responses. T lymphocytes have been shown to accumulate in the liver during MASH, but the cause and consequence of T cell accumulation in the liver remain unclear. Our study aimed to define the phenotype and T cell receptor diversity of T cells from human cirrhotic livers and an animal model of MASH to begin resolving their function in disease. Approach and ResultsIn these studies, we evaluated differences in T cell phenotype in the context of liver disease we isolated liver resident T cell populations from individuals with cirrhosis and a murine model of MASH. Using both 5 single cell sequencing and flow cytometry we defined the phenotype and T cell receptor repertoire of liver resident T cells during health and disease. ConclusionsMASH-induced cirrhosis and diet-induced MASH in mice resulted in the accumulation of activated and clonally expanded T cells in the liver. The clonally expanded T cells in the liver expressed markers of chronic antigenic stimulation, including PD1, TIGIT and TOX. Overall, this study establishes for the first time that T cells undergo antigen-dependent clonal expansion and functional differentiation during the progression of MASH. These studies could lead to the identification of potential antigenic targets that drive T cell activation, clonal expansion, and recruitment to the liver during MASH.

immunology↗

bioRxiv2017

Identification of a Small Molecule Inhibitor of the Aminoglycoside 6’-N-Acetyltransferase Type Ib [AAC(6’)-Ib] Using Mixture-Based Combinatorial Libraries

The aminoglycoside 6'-N-acetyltransferase type Ib [AAC(6)-Ib] is the most widely distributed enzyme among AAC(6)-I-producing Gram-negative pathogens and confers resistance to clinically relevant aminoglycosides including amikacin. This enzyme is therefore ideal to target with enzymatic inhibitors that could overcome resistance to aminoglycosides. The search for inhibitors was carried out using mixture-based combinatorial libraries, the scaffold ranking approach, and the positional scanning strategy. A library with high inhibitory activity had pyrrolidine pentamine scaffold and was selected for further analysis. This library contained 738,192 compounds with functionalities derived from 26 different amino acids (R1, R2 and R3) and 42 different carboxylic acids (R4) in four R group functionalities. The most active compounds all contained S-phenyl (R1 and R3) and S-hydromethyl (R2) functionalities at three locations and differed at the R4 position. The compound containing 3-phenylbutyl at R4 (compound 206) was a robust enzymatic inhibitor in vitro, in combination with amikacin potentiated the inhibition of growth of three resistant bacteria in culture, and improved survival when used as treatment of Galleria mellonella infected with aac(6)-Ib-harboring Klebsiella pneumoniae and Acinetobacter baumannii strains.

microbiology↗