A bradykinin-potentiating peptide (BPP-10c) from Bothrops jararaca induces changes in seminiferous tubules

Abstract

BackgroundThe testis-specific isoform of angiotensin-converting enzyme (tACE) is exclusively expressed in germ cells during spermatogenesis. Although the exact role of tACE in male fertility is unknown, it clearly plays a critical function in spermatogenesis. The dipeptidase domain of tACE is identical to the C-terminal catalytic domain of somatic ACE (sACE). Bradykinin potentiating peptides (BPPs) from snake venoms are the first natural sACE inhibitors described and their structure–activity relationship studies were the basis for the development of antihypertensive drugs such as captopril. In recent years, it has been showed that a number of BPPs – including BPP-10c – are able to distinguish between the N- and C-active sites of sACE, what is not applicable to captopril. Considering the similarity between tACE and sACE (and since BPPs are able to distinguish between the two active sites of sACE), the effects of the BPP-10c and captopril on the structure and function of the seminiferous epithelium were characterized in the present study. BPP-10c and captopril were administered in male Swiss mice by intraperitoneal injection (4.7 μmol/kg for 15 days) and histological sections of testes were analyzed. Classification of seminiferous tubules and stage analysis were carried out for quantitative evaluation of germ cells of the seminiferous epithelium. The blood-testis barrier (BTB) permeability and distribution of claudin-1 in the seminiferous epithelium were analyzed by hypertonic fixative method and immunohistochemical analyses of testes, respectively.ResultsThe morphology of seminiferous tubules from animals treated with BPP-10c showed an intense disruption of the epithelium, presence of atypical multinucleated cells in the lumen and degenerated germ cells in the adluminal compartment. BPP-10c led to an increase in the number of round spermatids and total support capacity of Sertoli cell in stages I, V, VII/VIII of the seminiferous epithelium cycle, without affecting BTB permeability and the distribution of claudin-1 in the seminiferous epithelium. Interestingly, no morphological or morphometric alterations were observed in animals treated with captopril.ConclusionsThe major finding of the present study was that BPP-10c, and not captopril, modifies spermatogenesis by causing hyperplasia of round spermatids in stages I, V, and VII/VIII of the spermatogenic cycle.

Angiotensin-converting enzyme inhibitors of Bothrops jararaca snake venom affect the structure of mice seminiferous epithelium

“…Nevertheless, it has been demonstrated that captopril and its derivatives did not affect tACE activity in vivo , thereby suggesting that these drugs do not cross the BTB, which would explain the absence of reports concerning the adverse effects of ACE inhibitors on testicular function [ 28 , 29 ]. However, we have demonstrated in previous studies that BPP-10c, the most potent and selective sACE C-domain inhibitor, modified spermatogenesis in mice treated by intraperitoneal injection without affecting BTB permeability or the distribution of claudin-1, a protein found at the site of the BTB [ 16 ]. It was very interesting to find that the effects are dependent on the primary molecular structure of BPP-10c, since no morphological or morphometric alterations in the seminiferous epithelium were found in the mice treated with (inv)BPP-10c, that contains the inverted BPP-10c sequence.…”

“…We have previously shown that BPP-10c is internalized by HUVEC, HEK293 and C6 cells in different experimental conditions [ 16 , 30 , 37 ]. These results are not surprising considering that BPPs are proline-rich peptides, a feature that endows these molecules with the properties of cell-penetrating peptides and resistance to proteolysis [ 27 ].…”

“…Captopril was purchased from Sigma Chemical Company (USA). BPP-10c, BPP-11e, BPP-AP and (inv)BPP-10c tested in present study were synthesized via solid phase peptide synthesis applying the Fmoc (9-fluorenylmethyloxycarbonyl) strategy [ 13 – 16 ]. The synthetic peptides were purified by preparative reversed-phase chromatography (reversed-phase HPLC), whereas the purity and identity of the peptide were confirmed by MALDI-TOF mass spectrometry on an Ettan MALDI-TOF/Pro instrument (Amersham Biosciences, USA).…”

“…The effect of BPPs derived from Bothrops jararaca snake venom on spermatogenesis in mice has been characterized by our group. Interestingly, we have demonstrated that BPP-10c, a potent selective C-domain inhibitor of sACE and not captopril, modified spermatogenesis in male Swiss mice treated for 15 consecutive days with a single dose of BPP-10c (4.7 μmol/kg/d) by intraperitoneal administration [ 16 ].…”

Toxins Are an Excellent Source of Therapeutic Agents against Cardiovascular Diseases

“…204,205 Currently, such peptides are being explored for the design of antihypertensive drugs. BPP-10c, a proline-rich decapeptide, 206 is a selective inhibitor of the active site at the C-domain of somatic ACE, which contains two active sites. 207 BPP-5a exerts a potent and long-lasting antihypertensive effect in spontaneously hypertensive rats (SHRs) through endothelium-and NO-dependent vasodilation.…”