Transglutaminase-mediated amine incorporation into substance P protects the peptide against proteolysis in vitro

Effects of an Extract of Salmon Milt on Symptoms and Serum TNF and Substance P in Patients With Fibromyalgia Syndrome

PURPOSE

The aim of this study was to evaluate the effects of a dietary supplement containing primarily an extract of salmon's milt (semen) on symptoms and blood levels of proinflammatory molecules in patients with fibromyalgia syndrome (FMS), a chronic, painful musculoskeletal disease without a distinct pathogenesis or treatment. We recently reported increased serum levels of the proinflammatory molecules substance P (SP) and tumor necrosis factor (TNF) in patients with FMS as compared to those in normal controls.

METHODS

This prospective, open-label study was conducted in patients with FMS (n = 87; 80 women, 7 men; age range, 18-80 years) selected from 2 clinical centers in Spain. Patients were administered the supplement and were evaluated at weeks 1 (before treatment), 4, 8, and 12 (end of treatment) for clinical parameters of functioning, fatigue, and pain, as well as overall impression. Patients were directed to take 1 capsule per day in the morning for the first 4 weeks, followed by 1 capsule in the morning and 1 capsule in the evening for the remaining 8 weeks. Differences in symptom scores in patients with FMS between weeks 1 and weeks 4, 8, and 12 were evaluated using ANOVA. Blood was obtained and serum separated in patients with FMS at 1 and 12 weeks and in a separate population of healthy controls (n = 20; 15 women, 5 men; age range, 25-65 years). Serum levels of SP and TNF were measured in patients with FMS at 1 and 12 weeks and in healthy controls by ELISA. TNF and SP levels in patients with FMS were compared between weeks 1 and 12, as well as between patients with FMS and untreated controls, using the Mann-Whitney U test.

FINDINGS

Clinical parameters of functioning, fatigue, and pain, as well as overall impression, were improved significantly at 4 weeks as compared to 1 week and remained unchanged for the duration of the study (all, P < 0.0001). Serum TNF and SP levels were significantly elevated at 1 week in patients with FMS compared to controls and were decreased significantly at 12 weeks as compared to 1 week (all, P < 0.0001).

IMPLICATIONS

Our findings indicate that this dietary supplement may significantly improve symptoms in patients with FMS. This is the first time to our knowledge that any molecule has been reported to be associated with a reduction in serum SP level. Consequently, the supplement or its hypothesized main active ingredient, spermine, may be developed as a novel treatment approach to FMS or other neuroinflammatory conditions. ClinicalTrials.gov identifier: NCT03911882.

Interactions of natural polyamines with mammalian proteins

The ubiquitously expressed natural polyamines putrescine, spermidine, and spermine are small, flexible cationic compounds that exert pleiotropic actions on various regulatory systems and, accordingly, are essentially involved in diverse life functions. These roles of polyamines result from their capability to interact with negatively charged regions of all major classes of biomolecules, which might act in response by changing their structures and functions. The present review deals with polyamine-protein interactions, thereby focusing on mammalian proteins. We discuss the various modes in which polyamines can interact with proteins, describe major types of affected functions illustrated by representative examples of involved proteins, and support information with respective structural evidence from elucidated three-dimensional structures. A specific focus is put on polyamine interactions at protein surfaces that can modulate the aggregation of proteins to organized structural networks as well as to toxic aggregates and, moreover, can play a role in important transient protein-protein interactions.

Putrescine-polysaccharide conjugates as transglutaminase substrates and their possible use in producing crosslinked films

Putrescine (1,4-diaminobutane) was covalently linked to alginate and low-methoxyl pectin to synthesize new aminated polysaccharides. Both putrescine-pectin and -alginate conjugates, although the latter at higher concentrations, were found to be able to act as effective acyl acceptor transglutaminase substrates in vitro using both dimethylated casein and soy flour proteins as acyl donors. Monodansylcadaverine, a well known acyl acceptor transglutaminase substrate, dose-dependently counteracted the covalent binding of the aminated polysaccharides to the proteins. Putrescine-pectin conjugate was also tested to prepare, in combination with soy flour proteins, edible films in the presence of purified microbial transglutaminase. Characterization of the enzymatically crosslinked films showed a significant decreased water vapor permeability, with respect to the ones obtained with non-aminated pectin in the presence of transglutaminase, as well as improved mechanical properties, such as high extensibility. Possible biotechnological applications of hydrocolloid films containing putrescine-polysaccharide derivatives enzymatically crosslinked to proteins were suggested.

Chitosan-whey protein edible films produced in the absence or presence of transglutaminase: analysis of their mechanical and barrier properties

Chitosan-whey protein edible films with different protein concentrations were prepared in the absence or presence of microbial transglutaminase as cross-linking agent. The films prepared in the presence of the enzyme showed low solubility at a wide range of pH, a lower degree of swelling, and good biodegradability following protease treatments. The presence of transglutaminase induced also an enhancement in film mechanical resistance and a reduction in their deformability. Finally, the barrier efficiency toward oxygen and carbon dioxide was found to be markedly improved in the cross-linked films which showed also a lower permeability to water vapor. Some potential practical applications of transglutaminase-treated chitosan-whey protein films are suggested.

Transglutaminase-catalyzed site-specific glycosidation of catalase with aminated dextran

An enzymatic approach, based on a transglutaminase-catalyzed coupling reaction, was investigated to modify bovine liver catalase with an end-group aminated dextran derivative. We demonstrated that catalase activity increased after enzymatic glycosidation and that the conjugate was 3.8-fold more stable to thermal inactivation at 55 degrees C and 2-fold more resistant to proteolytic degradation by trypsin. Moreover, the transglutaminase-mediated modification also improved the pharmacokinetics behavior of catalase, increasing 2.5-fold its plasma half-life time and reducing 3-fold the total clearance after its i.v. administration in rats.

Mammalian transglutaminases. Identification of substrates as a key to physiological function and physiopathological relevance

Transglutaminases form a large family of intracellular and extracellular enzymes that catalyse the Ca2+-dependent post-translational modification of proteins. Despite significant advances in our understanding of the biological role of most mammalian transglutaminase isoforms, recent findings suggest new scenarios, most notably for the ubiquitous tissue transglutaminase. It is becoming apparent that some transglutaminases, normally expressed at low levels in many tissue types, are activated and/or overexpressed in a variety of diseases, thereby resulting in enhanced concentrations of cross-linked proteins. As applies to all enzymes that exert their metabolic function by modifying the properties of target proteins, the identification and characterization of the modified proteins will cast light on the functions of transglutaminases and their involvement in human diseases. In this paper we review data on the properties of mammalian transglutaminases, particularly as regards their protein substrates and the relevance of transglutaminase-catalysed reactions in physiological and disease conditions.

Transglutaminase-catalyzed synthesis of trypsin-cyclodextrin conjugates: kinetics and stability properties

Bovine pancreatic trypsin was modified by the mono-6-amino-6-deoxy derivatives of alpha-, beta-, and gamma-cyclodextrin through a transglutaminase-catalyzed reaction. The trypsin-cyclodextrin conjugates, containing about 3 mol of oligosaccharide per mole of protein, were tested for their catalytic and stability properties. The specific esterolytic activity and the kinetics constants of trypsin were significantly improved following the transglutaminase-induced structural modifications. Trypsin-cyclodextrin conjugates were also found markedly (sixfold) more resistant to autolytic degradation at alkaline pH, and their thermal stability profile was improved by about 16 degrees C. Moreover, they were particularly resistant to heat inactivation when treated at different temperatures ranging from 45 degrees C to 70 degrees C for different periods of time.