Adverse effects of gossypol analogs on TM4 cell mitochondrial function

Three aqueous-soluble gossypol Schiff's bases, SP562: bis-8,8'-[(N-(2-(dimethylamino)ethyl]-iminomethylene]- 1,1',6,6',7,7'-hexahydroxy-5,5'-diisopropyl-3,3'-dimethyl-2,2'-binaphthalene dihydrochloride; SP563: bis-8,8'-[(N-(2-(diethylamino)ethyl]-iminomethylene]-1,1',6,6',7,7'- hexahydroxy-5,5'-diisopropyl-3,3'-dimethyl-2,2'-binaphthalene dihydrochloride; and SP564: bis-8,8'-[(N-(2-(diethylamino)propyl]-iminomethylene]-1,1',6,6',7,7'- [hexahydroxy-5,5'-diisopropyl-3,3'-dimethyl-2,2'-binaphthalene dihydrochloride, were examined for their effects on TM4 cell mitochondrial function and proliferation. Among the three gossypol analogs, SP562 had the most severe effect on decreasing TM4 cell population that accumulated rhodamine 123 into their mitochondria. This adverse effect exerted by SP562, however, was not as strong as that caused by (+/-) gossypol acetic acid of the same molarity. On the other hand, SP564 had the most severe effect on proliferation of TM4 cells. This severe effect was even more so than that caused by an equimolarity of (+/-) gossypol acetic acid.

Inhibitory effects of gossypol analogs on human sperm motility

Aqueous-soluble gossypol Schiff's bases, SP562: bis-8,8'-[(N-(2-(dimethylamino)ethyl]-iminomethylene]- [1,1',6,6',7,7'-hexahydroxy-5,5'-diisopropyl-3,3'-dimethyl-2,2- binaphthalene dihydrochloride; SP563: bis-8,8'-[(N-(2-(diethylamino)ethyl]-iminomethylene]-1,1',6,6',7,7 '- hexahydroxy-5,5'-diisopropyl-3,3'-dimethyl-2,2'-binaphthalene++ + dihydrochloride; and SP564: bis-8,8'-[(N-(2-(diethylamino)propyl]-iminomethylene]- 1,1',6,6',7,7'-hexahydroxy-5,5'-diisopropyl-3,3'-dimethyl-2,2'- binaphthalene dihydrochloride, were investigated for their effects on human sperm motility. SP564, which has the longest alkyl substituent of the Schiff's base, appeared to exert the greatest inhibitory effects on human sperm motility. These inhibitory effects were even greater than those caused by (+/-)gossypol acetic acid at the same concentration.

Incorporation of gossypol and formation of its protein conjugates in mouse transformed Sertoli (TM4) cells

Mitochondria of both mouse transformed Sertoli (TM4) cells and primary-cultured rat and mouse Sertoli cells were shown to be preferentially affected by gossypol (Tanphaichitr et al, 1984). To investigate whether this selective effect was due to a greater of TM4 cells to accumulate gossypol, TM4 and other somatic cell lines, including dog (MDCK) and kangaroo (PtK2) kidney epithelial cells, rat embryo fibroblasts (Rat-1) and mouse BALB/c 3T3 fibroblasts, were incubated with [14C]gossypol and the incorporated specific activity of the drug was assessed. The results indicate that TM4 cells accumulated [14C]gossypol at the highest level. Incorporated [14C]gossypol appeared to bind to TM4 cell macromolecules and remained in the dialysis tubing after extensive dialysis. Characterization of these gossypol-conjugated proteins by SDS-polyacrylamide gel electro-proteins had apparent Mr's of 92,500, 70,000, 63,200, 60,000, 58,100, 54,000, 52,000, 50,000, 47,500, 40,000 37,000, 35,000, 30,000, 20,000, and 14,500 daltons. Conjugation of these proteins with gossypol may result in macromolecular dysfunction and abnormal structure.

Differential effects of (+) and (-) gossypol enantiomers on mitochondrial function and proliferation of cultured TM4 cells

The in vitro effects of (+) and (-)gossypol enantiomers on the mitochondrial functions of mouse transformed Sertoli, TM4 cells were investigated by monitoring mitochondrial rhodamine 123 accumulation. When TM4 cells were cultured in medium without fetal calf serum, 5 micrograms/ml of both enantiomers caused similar declines in mitochondrial rhodamine 123 staining. By contrast, (-)gossypol had a greater adverse action than did (+)gossypol on the mitochondrial of TM4 cells that were cultured in medium supplemented with 2% fetal calf serum. Construction of dose response curves for the effects of the two enantiomers on rhodamine 123 accumulation by TM4 cells after 5 hr of drug treatment gave an EC50 of 7.5 micrograms/ml for the (-)gossypol isomer compared with 18 micrograms/ml for the (+)gossypol isomer. Similarly, TM4 cell proliferation was also more disturbed by (-)gossypol in medium supplemented with other concentrations of fetal calf serum. The results suggest that the lower effect of (+)gossypol on TM4 cells may be attributed to its higher affinity to serum components, which may impede its entrance into TM4 cells.

Comparison of the in vitro fertilization rate by human sperm capacitated by multiple-tube swim-up and Percoll gradient centrifugation

Two sperm preparation methods, a multiple-tube swim-up and Percoll-gradient centrifugation, were employed in our human in vitro fertilization program. The fertilization rate of these two sperm preparation methods was compared when they were employed in semen samples of less than 60 million motile sperm/ml. The results described here suggest that both of these methods gave a similar fertilization rate in these semen samples, i.e., 72 +/- 8% for the Percoll-gradient centrifugation method and 66 +/- 8% for the multiple-tube swim-up method.

Egg-penetration ability and structural properties of human sperm prepared by Percoll-gradient centrifugation

Human sperm with a high zona-free hamster egg-penetration ability were obtained by centrifuging freshly ejaculated sperm through a discontinuous two-step (47% and 90%) Percoll gradient at 600g at room temperature for 30 min. Highly motile sperm with good penetration ability were recovered in the pellet fraction (Per-sperm), whereas those with low penetration ability were in the gradient interface. The increased penetration ability of Per-sperm, as compared to sperm capacitated by other methods such as a single-tube swim-up or multiple-tube swim-up preparation, was not due to an increased proportion of acrosome reacted sperm. Rather, transmission electron microscopy indicated that Per-sperm were devoid of coating envelopes, which were present around both the head and tail regions of noncapacitated and single-tube swim-up sperm. Changes to the surface of Per-sperm were demonstrated by their decreased interaction with UEA I lectin, which binds specifically to fucose residues. Removal of the coating envelopes as well as other changes on the sperm surface may lead to an enhanced binding of Per-sperm to the oocyte. In addition, 99% of Per-sperm contained chromatin that was fully condensed. By contrast, about 15% of swim-up sperm still possessed incompletely condensed chromatin. With a higher penetration ability, "clean" appearance, and homogeneity of condensed chromatin, Per-sperm are recommended for insemination and studies of human sperm capacitation.

Aberrant protamine 1/protamine 2 ratios in sperm of infertile human males

Protamines were extracted from the sperm of fertile and infertile human males and the relative proportion of protamines 1, 2, and 3 were determined by scanning microdensitometry following electrophoresis of total protamine in polyacrylamide gels. The proportion of the three protamines was found to be similar in sperm obtained from different normal males. The distribution of protamines in sperm obtained from a select group of infertile males producing an elevated level of large sperm heads, in contrast, was different from that of the fertile males.

An increase in in vitro fertilization ability of low-density human sperm capacitated by multiple-tube swim-up

Comparison was made of the efficacy of multiple-tube swim-up (MT-SU) and single-tube swim-up (ST-SU) preparations on inducing human sperm fertilization ability in semen samples of less than 60 million motile sperm/ml. Two parallel groups of in vitro fertilization (IVF) patients possessing sperm density of this category had their sperm capacitated by MT-SU or ST-SU. The MT-SU patients' sperm fertilized 71 +/- 6.0% of eggs retrieved in comparison to 39 +/- 7.9% in the parallel ST-SU patients (P less than 0.001). Similarly, MT-SU increased the rate of human sperm penetration into zona-free hamster eggs. The increased fertilization rate of MT-SU sperm was not from acceleration of the acrosome reaction, but may be attributed to the higher efficiency of MT-SU in removing antifertility factors present in the seminal plasma from sperm.

Gossypol-induced damage to mitochondria of transformed Sertoli cells

Studies on gossypol-induced morphologic changes in transformed Sertoli cells (TM4) were performed at both light- and electron-microscopic levels. Exposure of TM4 cells to 5 micrograms gossypol/ml for greater than 1 hour has severe, deleterious effects on the structure and function of mitochondria. Mitochondrial function in TM4 cells was monitored by employing a fluorochrome, Rhodamine 123, which accumulates rapidly in mitochondria having a high transmembrane potential. In gossypol-treated TM4 cells, Rhodamine 123 mitochondrial staining was reduced significantly 1 hour after the drug addition and reached a minimal level at 3 hour. Concomitantly, cytoplasmic vacuoles were detected even at the light-microscopic level. Electron-microscopic studies revealed that these vacuoles were distended mitochondria. The morphology of these damaged organelles changed gradually, starting with the transformation of the tubular mitochondria into the rounded forms. Cristae concurrently collapsed onto the organelles' periphery. In addition, the ground matrixes disappeared, and the mitochondria appeared as empty vacuoles. Further evidence that these vacuoles were distended mitochondria was derived from the cytochemical localization of cytochrome c oxidase in these vacuole-like structures.

Energy metabolism of cultured TM4 cells and the action of gossypol

The energy metabolism of cultured TM4 cells, a cell line originally derived from mouse testicular cells, has been studied in relation to the action of gossypol. In the absence of externally added substrates, TM4 cells consumed oxygen at 37 +/- 5 nmoles O2 X mg protein-1 X h-1. Pyruvate stimulated oxygen consumption in a dose-dependent fashion up to 23%. Addition of glucose to the cells suspended in substrate-free medium inhibited oxygen consumption. At 5.5 mM glucose, the inhibition of oxygen consumption was 45 +/- 9%. The rate of aerobic lactate production from endogenous substrates was less than 7 nmoles lactate X mg protein-1 X h-1, even in the presence of optimal concentrations of the mitochondrial uncoupler carbonylcyanide m-chlorophenylhydrazone. The rate of aerobic lactate production was 920 +/- 197 nmoles X mg protein-1 X h-1 at external glucose concentrations of 2 mM or greater. The formation of aerobic glycolytic adenosine triphosphate (ATP) in 5 mM glucose comprised about 80% of the total ATP production. Gossypol stimulated both aerobic lactate production and oxygen consumption of the transformed testicular cells in a dose-dependent manner. The effect of gossypol on glucose transport, aerobic lactate production, and oxygen consumption is consistent with the hypothesis that gossypol modifies energy metabolism in these cells mainly by partially uncoupling mitochondrial oxidative phosphorylation. The possible impairment of cell and tissue function under gossypol treatment would depend on the metabolic properties of each specific differentiated cell.

Direct effect of gossypol on TR-ST cells: perturbation of rhodamine 123 accumulation in mitochondria

Gossypol has deleterious effects directly on TR-ST cells originating from a rat testicular tumor. Exposure of TR-ST cells to gossypol (5 micrograms/ml) decreases their rate of protein synthesis approximately 30% within 1 h and 65% by greater than 10 h, causes intracellular vacuolation, changes cell shape from cobblestone to a rounded conformation and inhibits cell proliferation. Yet, these gossypol-treated cells remain viable, as assessed by their ability to hydrolyze fluorescein diacetate. Gossypol also perturbs mitochondrial transmembrane potential in TR-ST cells, as demonstrated by marked changes in rhodamine 123 staining. Mitochondria of control TR-ST cells avidly accumulate rhodamine 123, but those in cells exposed to gossypol (greater than or equal to 5 micrograms/ml) for greater than 1 h fail to sequester the fluorochrome. Instead, the cell cytoplasm shows a light and diffuse staining with rhodamine 123. Rat spermatozoa show a similar response. Conversely, at concentrations of 20 micrograms/ml, gossypol has minimal effects on rhodamine 123 accumulation by primary cultures of hepatocytes and by rat spermatogenic cells, including primary spermatocytes and spermatids (Steps 1-12). Moreover, TR-ST cells exhibit reduced mitochondrial staining with gossypol at an ED50 of 7.6 micrograms/ml, while those for the nontesticular Rat-1, AnAn, 3T3 and PtK2 cell lines are 13.1, 21.5, 28.5 and 26.4 micrograms/ml, respectively.

Molecular mechanisms of gossypol action on lipid membranes

Gossypol, an aldehyde extracted from cotton plants, produces both general toxic and antifertility effects in mammals. The cellular mechanisms by which gossypol exerts these effects are not understood. In this study, we have characterized the interactions of gossypol with lipid monolayer and bilayer membranes in order to assess if the drug acts by modifying the electrochemical properties of membranes. The charged form of gossypol binds to monolayers of different lipid compositions with apparent dissociation constants ranging from 0.7 to 2 microM. Binding of charged gossypol decreases the interfacial potential by 80-235 mV, the magnitude of this decrease being dependent upon the lipid composition. Gossypol also induces a conductance in phospholipid bilayer membranes. The relation between steady-state bilayer conductance versus gossypol concentration indicates that the current-carrying species is a single molecule of gossypol. The increase in bilayer conductance is accompanied by an increase in proton permeability. These changes induced by gossypol in model membranes can account for the mitochondrial uncoupling effects of this molecule and may be responsible for the inhibitory effects of gossypol on several membrane transport systems.

Transmission and scanning electron microscopic studies of human sperm heads extracted with 8 M urea, 1% mercaptoethanol and different concentrations of salt

Transmission (TEM) and scanning (SEM) electron microscopic studies were performed on the human sperm heads extracted with (a) 1% Triton X-100, 1% mercaptoethanol (ME) and (b) 8 M urea, 1% ME together with increasing concentrations of NaCl ranging from 0.2 to 0.6 M. In the TEM study, the extraction of the nuclear material was first observed when the heads were treated with 8 M urea and 1% ME, with the majority of the chromatin remaining as 400-550 A thick interconnecting cords and oval bodies. At 0.2 M NaCl the cords and bodies were further separated but linked together by extremely thin 20-50 A fibers. Between 0.3 and 0.5 M NaCl the chromatin bodies within the sperm heads began to be extracted, first at the central part and progressively towards the periphery. Finally, at 0.6 M NaCl only the chromatin cords forming the periphery of the heads remained. In the SEM study, the sperm heads remained unbroken up to the treatment with 8 M urea, 1% ME and 0.2 M NaCl. Between 0.3 M and 0.5 M NaCl the majority of heads were disrupted to form interlacing chromatin cords of 400-550 A thick while the unbroken heads exhibited surface with cross-weaving cords. At 0.6 M NaCl all heads were disrupted and the remaining chromatin existed mostly as exoskeleton of former sperm heads. Protein gel electrophoresis showed that histones and nonhistones were removed from the chromatin when the treatment reached 0.2 M NaCl, whereas protamines started to be removed at 0.3 M, and totally removed at 0.6 M NaCl; HP1 was the first protamine fraction to be extracted.(ABSTRACT TRUNCATED AT 250 WORDS)

Electron microscopic and biochemical analyses of the organization of human sperm chromatin decondensed with sarkosyl and dithiothreitol

Human sperm chromatin was decondensed by treating the purified sperm heads with Sarkosyl for 60 minutes followed with dithiothreitol (DTT) for 20 minutes and overnight. Following Sarkosyl treatment all histones and nonhistones were removed; the remaining nucleoprotamines in the sperm heads exhibited two levels of higher-order structure in the forms of 900-1200 A thick and 380-520 A thin knobby cords, which were randomly coiled. Subsequent treatment with DTT resulted in the dissociation of the 380-520 A cords into subunits of 180-210 A fibers, which were further decondensed into beads-on-a-string structure with diameter of the beads about 120-150 A.

Scanning electron microscopic study of the tegumental surface of adult Schistosoma mekongi

The surface topography of the tegument of adult Schistosoma mekongi was studied by scanning electron microscopy (SEM). In comparison to other species of human schistosomes the male tegument lacks tubercles and, except in the gynecophoral canal, also lacks spines; instead the surface is composed chiefly of trabeculae of highly perforated ridges which give it the 'spongy' appearance. In addition, there are 3 kinds of papillae interspersed on the surface among the ridges. The first is a doughnut-shaped papilla with a central crater which is most abundant on the ventral surface of the anterior part, on the floor of the gynecophoral canal and on the dorsal-lateral aspect of the tail. The second is a pleomorphic papilla with irregular shape and size, which is scattered throughout the dorso-lateral aspect of the middle part of the body. The third type of papilla has a uniform hemispherical shape, possesses a cilium projecting from its apex and probably corresponds to the 'sensory papilla' found in other species. The tegument of the female differs from that of the male by having numerous short spines over the whole surface; however, the pleomorphic papillae are much fewer in number and the ridges are much less developed than those of the male tegument; complex trabeculae are absent.

Transmission and scanning electron microscopic studies of the human sperm chromatin decondensed by micrococcal nuclease and salt

The human sperm chromatin was gently decondensed by treating the sperm head sequentially with micrococcal nuclease and 2 M NaCl. All histones, about 10% of DNA, and a small amount of degraded protamines were released into the soluble fraction, leaving mainly nucleoprotamines in the pellet fraction. Transmission and scanning electron microscopic studies revealed that the nucleoprotamine pellet consisted of chromatin cords of two dimensions, viz., 330- to 420-A and 650- to 1200-A thick cords laced together by very fine strands of 60- to 80-A fibers; both types of cord appeared knobby and had zig-zag patterns throughout their length. It appeared that these cords were derived from two types of sperm heads of approximately equal population; one type contained chiefly the thick cords and the other chiefly the thin cords. Further treatment of the pellet nuclease-NaCl with urea and mercaptoethanol resulted in the dissociation of the thick into the thin cords and unravelling of the thin cords into smaller sized fibers; whereas the treatment of the pellet nuclease-NaCl with DNAase I resulted in the disappearance of the 60- to 80-A fibers, and the remaining cords were chiefly of thick type together with the sperm head exoskeletons. From these results the packing order of the chromatin in human sperm was proposed.

Electron microscopic studies of rat sperm heads treated with urea, dithiothreitol, and micrococcal nuclease

Urea and dithiothreitol can decondense the chromatin in some of rat sperm heads. By this treatment, we have observed that in the nuclei of rat sperm the chromatin is organized into two morphologically distinct portions, namely: the compact chromatin rods of about 450 to 1,000 A thick, and the interlacing fibers about 250-290 A in thickness. When these treated sperm are further digested with micrococcal nuclease, the small fibers disappear, whereas the chromatin rods are still present in the "urea-nuclease pellet." From the available evidence, we suggest that the chromatin rods represent the highly packed nucleoprotamine, whereas the small fibers represent the more loosely organized nucleohistone.

Levels of L-carnitine and L-O-acetylcarnitine in normal and infertile human semen: a lower level of L-O-acetycarnitine in infertile semen

The level of total L-carnitine was determined in normal human seminal plasma and sperm. Most of the L-carnitine is concentrated in the seminal plasma and its level is about 10 times higher than that in blood plasma. About 50% of total L-carnitine in normal human seminal plasma exists in the form of acetylcarnitine. Similar studies were also carried out in oligospermic and azoospermic human seminal plasma. The level of L-O-acetylcarnitine in both types of infertile samples is significantly lower than that in normal samples. On the other hand, the level of free L-carnitine is the same in fertile and infertile seminal plasma.

Production of high levels of phosphorylated F1 histone by zinc chloride

Methods have been sought to perturb the level of phosphohistones. ZnCl2 (10 mM) exhibits histone phosphate phosphatase in vivo in HTC cells and leads to hyperphysiological levels of F1 phosphohistone. Treatment of tissue culture cells with this concentration of ZnCl2 leads to a reduction in medium pH to 6.4. Control experiments have indicated that HTC cells grow efficiently at this pH and that the reduction of pH does not produce the hyperphosphorylated state per se. The optimum conditions for the ZnCl2 effect are described. That the effect of ZnCl2 on the heterogeneity of F1 histone is due to an effect on phosphorylation was demonstrated by the observation that the entire effect is abolished by treatment with alkaline phosphatase. The site of phosphorylation is in the carboxy-terminal end of the F1 molecule. The inhibitory effect of ZnCl2 on F3 phosphorylation in metaphase cells is also described.

Relationship between chromosome condensation and metaphase lysine-rich histone phosphorylation

Treatment of metaphase HTC cells with ZnCl2 inhibits histone phosphatase activity and leads to an increase in the hyperphosphorylated forms of the lysine-rich (F1) histone. Under normal conditions a massive phosphatase activity is triggered as the cells shift from M into G1 phase. In the presence of ZnCl2 this activity is abolished and thehyperphosphorylated form of F1 persists intact into G1. We have asked the simple question of whether the chromosome can still extend during the M-G1 transition even if the F1 histone is maintained in the hyperphosphorylated form. We observe an apparently normal extension os the chromosomal material under these conditions, though it is evident that high levels of ZnCl2 have rather substantial effects on other cell functions.