Fluorocyclines. 1. 7-fluoro-9-pyrrolidinoacetamido-6-demethyl-6-deoxytetracycline: a potent, broad spectrum antibacterial agent.

This and the accompanying report (DOI: 10.1021/jm201467r ) describe the design, synthesis, and evaluation of a new generation of tetracycline antibacterial agents, 7-fluoro-9-substituted-6-demethyl-6-deoxytetracyclines ("fluorocyclines"), accessible through a recently developed total synthesis approach. These fluorocyclines possess potent antibacterial activities against multidrug resistant (MDR) Gram-positive and Gram-negative pathogens. One of the fluorocyclines, 7-fluoro-9-pyrrolidinoacetamido-6-demethyl-6-deoxytetracycline (17j, also known as TP-434, 50th Interscience Conference on Antimicrobial Agents and Chemotherapy Conference , Boston, MA , September 12-15, 2010 , poster F1 - 2157 ), is currently undergoing phase 2 clinical trials in patients with complicated intra-abdominal infections (cIAI).

Fluorocyclines. 2. Optimization of the C-9 side-chain for antibacterial activity and oral efficacy.

Utilizing a fully synthetic route to tetracycline analogues, the C-9 side-chain of the fluorocyclines was optimized for both antibacterial activity and oral efficacy. Compounds were identified that overcome both efflux (tet(K), tet(A)) and ribosomal protection (tet(M)) tetracycline-resistance mechanisms and are active against Gram-positive and Gram-negative organisms. A murine systemic infection model was used as an oral efficacy screen to rapidly identify compounds with oral bioavailability. Two compounds were identified that exhibit both oral bioavailability in rat and clinically relevant bacterial susceptibility profiles against major respiratory pathogens. One compound demonstrated oral efficacy in rodent lung infection models that was comparable to marketed antibacterial agents.

Synthesis and antibacterial activity of pentacyclines: a novel class of tetracycline analogs.

Employing a highly efficient total synthesis approach, we synthesized and evaluated for antibacterial activity diverse and novel pentacycline analogs with systematic variations at C7, C8, C9, and C10. Certain substitution groups, as well as substitution patterns at various positions, were found to be preferred for increased antibacterial activity. A number of pentacycline analogs displayed potent activity in vitro and in vivo, especially against Gram-positive organisms. Several analogs have also shown promising oral bioavailability in rats and cynomolgus monkey.

8-Azatetracyclines: synthesis and evaluation of a novel class of tetracycline antibacterial agents.

A novel series of fully synthetic 8-azatetracyclines was prepared and evaluated for antibacterial activity. Compounds were identified that overcome both efflux (tet(K)) and ribosomal protection (tet(M)) tetracycline resistance mechanisms and are active against Gram-positive and Gram-negative organisms. Two compounds were identified that exhibit comparable efficacy to marketed tetracyclines in in vivo models of bacterial infection.

Evaluation of the roles of apoptosis, autophagy, and mitophagy in the loss of plating efficiency induced by Bax expression in yeast.

We found recently that, in yeast cells, the heterologous expression of Bax induces a loss of plating efficiency different from that induced by acute stress because it is associated with the maintenance of plasma membrane integrity (Camougrand, N., Grelaud-Coq, A., Marza, E., Priault, M., Bessoule, J. J., and Manon, S. (2003) Mol. Microbiol. 47, 495-506). Bax effects were neither dependent on the presence of the yeast metacaspase Yca1p and the apoptosis-inducing factor homolog nor associated with the appearance of typical apoptotic markers such as metacaspase activation, annexin V binding, and DNA cleavage. Yeast cells expressing Bax instead displayed autophagic features, including increased accumulation of Atg8p, activation of vacuolar alkaline phosphatase, and the presence of autophagosomes and autophagic bodies. However, the inactivation of autophagy did not prevent and actually slightly accelerated Bax-induced loss of plating efficiency. On the other hand, Bax expression induced a fragmentation of the mitochondrial network, which retained, however, some level of organization in wild-type cells. However, when expressed in cells inactivated for the gene UTH1, previously shown to be involved in mitophagy, Bax induced a complete disorganization of the mitochondrial network. Interestingly, although mitochondrially targeted green fluorescent protein was slowly degraded in the wild-type strain, it remained unaffected in the mutant. Furthermore, the slow loss of plating efficiency in the mutant strain correlated with a loss of plasma membrane integrity. These data suggest that Bax-induced loss of growth capacity is associated with maintenance of plasma membrane integrity dependent on UTH1, suggesting that selective degradation of altered mitochondria is required for a regulated loss of growth capacity.