Erythromycin inhibition of cell proliferation and in vitro mitochondrial protein synthesis in human HeLa cells is pH dependent

Antibiotics with therapeutic effects on spinal cord injury: a review

Accumulating evidence indicates that a considerable number of antibiotics exert anti-inflammatory and neuroprotective effects in different central and peripheral nervous system diseases including spinal cord injury (SCI). Both clinical and preclinical studies on SCI have found therapeutic effects of antibiotics from different families on SCI. These include macrolides, minocycline, β-lactams, and dapsone, all of which have been found to improve SCI sequels and complications. These antibiotics may target similar signaling pathways such as reducing inflammatory microglial activity, promoting autophagy, inhibiting neuronal apoptosis, and modulating the SCI-related mitochondrial dysfunction. In this review paper, we will discuss the mechanisms underlying therapeutic effects of these antibiotics on SCI, which not only could supply vital information for investigators but also guide clinicians to consider administering these antibiotics as part of a multimodal therapeutic approach for management of SCI and its complications.

Neuroprotective effects of erythromycin on ischemic injury following permanent focal cerebral ischemia in rats

OBJECTIVE

This study aims to determine if erythromycin provides neuroprotective effects against ischemic injury following permanent focal cerebral ischemia.

METHODS

Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO). Each animal received a single subcutaneous injection of erythromycin lactobionate (EM, 50 mg/kg) or vehicle immediately after ischemia. The infarct volume, edema index and neurological performance were evaluated at 24 and 72 h after MCAO. The cerebral blood flow (CBF) was measured with an MRI system at 30 min after MCAO. TUNEL staining and immunohistochemical analyses for oxidative stress (4-HNE, 8-OHdG) and inflammation (Iba-1, TNF-α) in the cortex were conducted at 24 and 72 h after MCAO.

RESULTS

The CBF did not differ between the EM-treated and vehicle-treated groups. The EM treatment significantly reduced the infarct volume (p < 0.01) at 24 and 72 h after MCAO and significantly reduced the edema index (p < 0.01) at 24 h. The EM treatment significantly improved the neurological deficit scores (p < 0.05) at 24 and 72 h. EM also significantly suppressed the accumulation of 4-HNE (p < 0.01) and 8-OHdG (p < 0.01) and markedly reduced Iba-1 (p < 0.01) and TNF-α expression (p < 0.05) at both time points. The EM treatment significantly reduced TUNEL-positive cells (p < 0.01) at both time points.

CONCLUSION

These findings suggest that EM can protect against the neuronal damage caused by cerebral ischemia by alleviating inflammation and reducing oxidant stress.

Neuroprotective effects of erythromycin on cerebral ischemia reperfusion-injury and cell viability after oxygen-glucose deprivation in cultured neuronal cells

This study aims to determine if erythromycin has neuroprotective effects against transient ischemia and oxygen-glucose deprivation (OGD) in cultured neuronal cells. Sprague-Dawley rats were subjected to middle cerebral artery occlusion for 90 min, followed by reperfusion. The animals received a subcutaneous single injection of erythromycin lactobionate (EM, 50mg/kg) or vehicle immediately after ischemia. Infarct volume, edema index, and neurological performance were evaluated at 24 and 72 h after reperfusion. Immunohistochemical analyses for oxidative stress (4-HNE, 8-OHdG) and inflammation (Iba-1, TNF-α) were conducted in the cortex at 24h. Primary cortical neuronal cell cultures were prepared from the cerebral cortices of the animals and then subjected to OGD for 3h. Ten or 100 μM EM was added before OGD to determine the effect of EM on cell viability after OGD. EM significantly reduced infarct volume (p<0.01) and edema volume (p<0.05) and improved neurological deficit scores (p<0.05) at 24 and 72 h. EM significantly suppressed the accumulation of 4-HNE (p<0.01) and 8-OHdG (p<0.01) and markedly reduced Iba-1 (p<0.01) and TNF-α expression (p<0.01). Treatment with 100 μM EM in vitro significantly reduced cell death after OGD. EM reduces neuronal damage following cerebral ischemia and OGD and may have antioxidant and anti-inflammatory effects.

Plant ribosome recycling factor homologue is a chloroplastic protein and is bactericidal in escherichia coli carrying temperature-sensitive ribosome recycling factor

We have isolated a protein, mature RRFHCP, from chloroplasts of spinach (Spinacia oleracea L.) that shows 46% sequence identity and 66% sequence homology with ribosome recycling factor (RRF) of Escherichia coli. RRF recycles ribosomes through disassembly of the posttermination complex. From the cDNA analysis and from the amino-terminal sequencing of the isolated protein, the mature RRFHCP was deduced to have a Mr of 21,838 with 193 aa. It lacks the 78-aa chloroplast targeting sequence encoded by the RRFHCP cDNA sequence. The RRFHCP synthesized in vitro was imported into isolated chloroplasts with simultaneous conversion to the mature RRFHCP. Transcription of the gene coding for RRFHCP was not dependent on light, yet it was limited mostly to photosynthetic tissues in which only one transcript size was detected. Mature RRFHCP exerted a bactericidal effect on E. coli carrying temperature-sensitive RRF at the permissive temperature whereas wild-type E. coli was not affected.

Sequence analysis of mouse mitochondrial chloramphenicol-resistant mutants

The nucleotide sequences of the 3' halves of the mitochondrial 16S rRNA genes from four independent mouse chloramphenicol-resistant (CAP-R) mutants were determined. Each contained a different, single base change that encodes the mutational phenotype. The mitochondrial rRNA gene from the SVA31 CAP-R mutant contains a G-to-A transition at nucleotide 2161 of the noncoding strand; the SVIS CAP-R mutant, a G-to-A transition at position 2375; the LA9 CAP-R mutant, an A-to-T transversion at position 2379; and the SVT2 CAP-R mutant, a T-to-C transition at position 2433. Three of these CAP-R mutants appear to be heteroplasmic as the mtDNA populations contain both wild-type and mutant copies of the rRNA gene. The SVIS CAP-R mutation has not been observed in other mammalian CAP-R mutants, although it occurs at a site homologous to one of the yeast mitochondrial CAP-R mutations. Based upon the locations of the mutated sites within the 16S rRNA, and their proximity to previously analyzed sites of mutations conferring increased inhibitor resistance, all these mutations occur within the ribosomal RNA peptidyltransferase domain. These results provide an explanation for the pleiotropic nature of mitochondrial CAP-R mutations in mammalian cells, particularly the observations that some of the mutant lines are partially respiration deficient.