Identification of a binding site for the anti-inflammatory tripeptide feG

A novel biomarker associated with distress in humans: calcium-binding protein, spermatid-specific 1 (CABS1)

Calcium-binding protein spermatid-specific 1 (CABS1) is expressed in the human submandibular gland and has an anti-inflammatory motif similar to that in submandibular rat 1 in rats. Here, we investigate CABS1 in human saliva and its association with psychological and physiological distress and inflammation in humans. Volunteers participated across three studies: 1) weekly baseline measures; 2) a psychosocial speech and mental arithmetic stressor under evaluative threat; and 3) during academic exam stress. Salivary samples were analyzed for CABS1 and cortisol. Additional measures included questionnaires of perceived stress and negative affect; exhaled nitric oxide; respiration and cardiac activity; lung function; and salivary and nasal inflammatory markers. We identified a CABS1 immunoreactive band at 27 kDa in all participants and additional molecular mass forms in some participants. One week temporal stability of the 27-kDa band was satisfactory (test-retest reliability estimate = 0.62-0.86). Acute stress increased intensity of 18, 27, and 55 kDa bands; 27-kDa increases were associated with more negative affect and lower heart rate, sympathetic activity, respiration rate, and minute ventilation. In both acute and academic stress, changes in 27 kDa were positively associated with salivary cortisol. The 27-kDa band was also positively associated with VEGF and salivary leukotriene B4 levels. Participants with low molecular weight CABS1 bands showed reduced habitual stress and negative affect in response to acute stress. CABS1 is readily detected in human saliva and is associated with psychological and physiological indicators of stress. The role of CABS1 in inflammatory processes, stress, and stress resilience requires careful study.

Calcium-binding protein, spermatid-specific 1 is expressed in human salivary glands and contains an anti-inflammatory motif

Salivary glands are involved in the production and exocrine and endocrine secretion of biologically active proteins, polypeptides, and hormones involved in growth and differentiation, homeostasis, and digestion. We have previously studied the prohormone submandibular rat 1 (SMR1), product of the Vcsa1 gene, which is highly expressed in the testes and salivary glands of rats, and can be cleaved to produce polypeptides with analgesic, erectile function, and anti-inflammatory activities. Humans lack the Vcsa1 gene, but homologous sequences and functions for analgesia and erectile function exist in the human genes Prol1, SMR3a, and SMR3b located on the human chromosomal region close to where Vcsa1 lies in the rat. Here we show the human protein calcium-binding protein spermatid-specific 1 (CABS1) contains a similar sequence to the anti-inflammatory sequence in rat SMR1, thus CABS1 may be another human gene with homologous function to Vcsa1. Using Western blot and PCR, we discovered that the human protein CABS1, previously thought to only be expressed in the testes, is also expressed in the salivary glands and lung, in a tissue-specific manner. Peptides derived from CABS1 were tested in an in vivo mouse model of lipopolysaccharide (LPS)-induced neutrophilia and an ex vivo rat model of antigen-induced intestinal anaphylaxis and significantly reduced both neutrophil accumulation in bronchoalveolar lavage fluid and antigen-induced ileal contractions, respectively. Thus human CABS1 has a peptide motif homologous to the anti-inflammatory peptide sequence of rat SMR1. Whether this similarity of CABS1 extends to the neuroendocrine regulation of the anti-inflammatory activity seen for SMR1 remains to be determined.

Effects of a novel tripeptide on neurological outcomes after spinal cord injury

A biologically active tripeptide [phenylalanine glutamate glycine (feG)] derived from the submandibular gland has anti-inflammatory actions. We have shown that intravenous treatment with feG after spinal cord injury decreases the intraspinal infiltration of leukocytes and associated oxidative damage within 72 h after injury. The present study assessed effects of this treatment on chronic neurological outcomes after clip-compression spinal cord injury at the 12th thoracic segment. Locomotor scores of feG-treated rats were significantly higher than those of controls at 7 weeks after spinal cord injury. Treated rats had significantly less hind paw mechanical allodynia than controls at this time. In conclusion, the anti-inflammatory and anti-oxidative actions of feG treatment correlate with improved neurological outcomes after spinal cord injury.

The tripeptide phenylalanine-(d) glutamate-(d) glycine modulates leukocyte infiltration and oxidative damage in rat injured spinal cord

The tripeptide, phenylalanine-glutamate-glycine (FEG) and its d-isomeric form phenylalanine-(D) glutamate-(D) glycine (feG), derived from submandibular gland peptide-T, significantly reduce the allergic inflammatory response and leukocyte trafficking and neutrophil migration into intestine, heart and lungs. Due to these actions, we hypothesized that feG would attenuate the early inflammatory response to spinal cord injury, reduce free radical production and improve neurological outcomes, like other leukocyte-limiting strategies we have used previously. We tested this using a clip compression model of spinal cord injury in rats. Following spinal cord injury at the 4th thoracic cord segment, we quantified leukocyte infiltration, free radical formation and oxidative damage at the lesion site after feG or control peptide phenylalanine-(D) aspartate-(D) glycine treatment. In rats treated with feG at 2 and 12 h, or 6 and 12 h after spinal cord injury, mean myeloperoxidase activity and ED-1 expression were significantly lower ( approximately 40%) than in controls at 24 h. Free radical formation generated in injured spinal cord was detected using 2',7'-dichlorofluorescin-diacetate as a fluorescent probe. Free radical production in the injured cord increased significantly after spinal cord injury and feG treatment significantly reduced this free radical production. Oxidative enzymes, lipid peroxidation and cell death were also significantly ( approximately 40%), gp91 ( approximately 30%), thiobarbituric acid reactive substance levels ( approximately 35%), 4-hydroxynonenal-bound protein ( approximately 35%) and caspase-3 ( approximately 32%). Early administration of feG decreases infiltration of inflammatory cells into the injured spinal cord and intraspinal free radical formation, thereby reducing oxidative damage and secondary cell death after spinal cord injury.

Effects of peptides, with emphasis on feeding, pain, and behavior A 5-year (1999-2003) review of publications in Peptides

Novel effects of naturally occurring peptides are continuing to be discovered, and their mechanisms of actions as well as interactions with other substances, organs, and systems have been elucidated. Synthetic analogs may have actions similar or antagonistic to the endogenous peptides, and both the native peptides and analogs have potential as drugs or drug targets. The journal Peptides publishes many leading articles on the structure-activity relationship of peptides as well as outstanding reviews on some families of peptides. Complementary to the reviews, here we extract information from the original papers published during the past five years in Peptides (1999-2003) to summarize the effects of different classes of peptides, their modulation by other chemicals and various pathophysiological states, and the mechanisms by which the effects are exerted. Special attention is given to peptides related to feeding, pain, and other behaviors. By presenting in condensed form the effects of peptides which are essential for systems biology, we hope that this summary of existing knowledge will encourage additional novel research to be presented in Peptides.