ABSTRACT
The formyltetrapeptides for-Met-Leu-Leu-Phe-OMe 1, for-Met-Leu-Aib-Phe-OMe 2, for-Met-Leu-Ac6c-Phe-OMe 3, for-Met-Leu-Pro-Phe-OMe 4, for-Met-Pro-Pro-Phe-OMe 5, for-Met-Aib-Aib-Phe-OMe 6, for-Met-Pro-Aib-Phe-OMe 7 and for-Met-Aib-Pro-Phe-OMe 8 were synthesized and biologically tested on human neutrophils in an attempt to evaluate the specific receptor pocket dimensions and features. Our results indicate that the shift in the Phe residue to the fourth position in these compounds strongly reduces chemotactic response, but is efficacious in triggering superoxide anion production and lysozyme release (order of potency 3 > 2 > 1 > 4 > 6 > 8 > 5 > 7). The potency of the two latter responses correlates well with the affinity data obtained in binding experiments.
Subject(s)
Chemotactic Factors/chemistry , N-Formylmethionine Leucyl-Phenylalanine/chemistry , Neutrophils/drug effects , Amino Acid Sequence , Chemotactic Factors/pharmacology , Chemotaxis, Leukocyte/drug effects , Cytoplasmic Granules/drug effects , Cytoplasmic Granules/enzymology , Humans , In Vitro Techniques , Magnetic Resonance Spectroscopy , Muramidase/metabolism , N-Formylmethionine Leucyl-Phenylalanine/pharmacology , Neutrophils/enzymology , Neutrophils/metabolism , Structure-Activity Relationship , Superoxides/metabolismSubject(s)
Receptors, Immunologic/antagonists & inhibitors , Receptors, Peptide/antagonists & inhibitors , Humans , In Vitro Techniques , Molecular Conformation , N-Formylmethionine Leucyl-Phenylalanine/metabolism , Neutrophils/metabolism , Peptides/chemical synthesis , Peptides/chemistry , Peptides/pharmacology , Receptors, Formyl Peptide , Receptors, Immunologic/chemistry , Receptors, Peptide/chemistry , Structure-Activity Relationship , Superoxides/metabolismABSTRACT
In order to further investigate the potential of rifamycins as antiinflammatory drugs, twenty-five semisynthetic rifamycins were tested at concentrations ranging from 10(-9) to 10(-5) M on in vitro human neutrophil functions such as locomotion, superoxide anion production, and degranulation, under different stimulatory conditions. They were also tested as antiproliferative agents on peripheral blood lymphocytes. The present semisynthetic derivatives are in general characterized by their carrying a hydrophilic substituent; they are rifamycin S or rifamycin SV derivatives carrying at C(3) either a carboxyalkyl side-chain or a glycosyl side-chain. Derivatives of the former group displayed inhibitory activities covering the whole range of activities tested, suggesting that the sum of these different effects could support their antiinflammatory activity in vivo. These derivatives, carrying a free carboxyl, are more water soluble than rifamycin SV at physiological pH, and may serve as antiinflammatory drugs for local administration, alternative to rifamycin SV, possibly giving higher efficacy and reduced side effects of pain and tissue swelling.
Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Neutrophils/drug effects , Neutrophils/physiology , Rifamycins/chemistry , Rifamycins/pharmacology , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Cell Degranulation/drug effects , Cell Movement/drug effects , Humans , In Vitro Techniques , Respiratory Burst/drug effects , Structure-Activity Relationship , Superoxides/metabolismABSTRACT
In order to obtain an insight into the mode of binding at the for-Met-Leu-Phe-OH (fMLP) receptor, three fMLP-OMe analogs (1-3) were synthesized in which the Met residue was substituted by Gln 1, Asn 2, and Ser 3. We evaluated the influence of the charge variation and/or the shift of its position on neutrophil biological responses.
Subject(s)
Chemotactic Factors/pharmacology , N-Formylmethionine Leucyl-Phenylalanine/analogs & derivatives , N-Formylmethionine Leucyl-Phenylalanine/pharmacology , Receptors, Immunologic/drug effects , Receptors, Peptide/drug effects , Chemotactic Factors/chemistry , Chemotactic Factors/metabolism , Humans , N-Formylmethionine Leucyl-Phenylalanine/chemistry , N-Formylmethionine Leucyl-Phenylalanine/metabolism , Neutrophils/drug effects , Receptors, Formyl Peptide , Receptors, Immunologic/metabolism , Receptors, Peptide/metabolism , Structure-Activity RelationshipABSTRACT
In our study we investigated the effect of rifamycin SV, rifamycin B, rifampicin and five semisynthetic derivatives on human neutrophil functions such as locomotion, superoxide production and degranulation stimulated by specific agonists. All compounds were tested at concentrations ranging from 10(-9) to 10(-5) M. Among the newly synthesized compounds the most active we found to be the derivatives carrying an acidic substituent at C3: these significantly lowered the superoxide generation induced by PMA throughout the entire concentration range, whereas rifamycin SV, rifamycin B and rifampicin were effective only at the highest concentrations. Moreover, chemotactic movement was significantly attenuated by derivative R4, rifamycin B and rifamycin SV at high doses; granule enzyme release was unaffected by all compounds.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Neutrophils/drug effects , Rifamycins/pharmacology , Cell Degranulation/drug effects , Cell Movement/drug effects , Chemotaxis, Leukocyte/drug effects , Humans , Neutrophils/physiology , Respiratory Burst/drug effectsABSTRACT
The formylpeptides formyl-L-methionyl-L-leucyl-L-N-methylphenylalanine methyl ester 1, formyl-L-methionyl-L-leucyl-L-2-oxy-3-phenylpropionic acid methyl ester 2 and formyl-L-methionyl-L-leucyl-L-2-aminoxy-3-phenylpropionic acid methyl ester 3 were synthesized to investigate the role of the amide bond at position 3 in biological activity in human neutrophiles. Our results indicate that this amide bond is required for optimal chemotactic activity, but not for superoxide anion production.
