P-791 In vitro production of mouse sperm on artificial testis engineered by 3D printing of extracellular matrix

Study question

Are testicular extracellular matrix (T-ECM)-based scaffolds fully capable of supporting mouse in vitro spermatogenesis?

Summary answer

In the future, 3D printing using T-ECM could be used to provide mature sperm for fertility restoration in new infertility treatments.

What is known already

Since autotransplantation of spermatogonial stem cells (SSCs) obtained from malignant samples is more likely to result in cancer recurrence, in vitro sperm production is considered to be a safer method of fertility preservation. Given the difficulty of evaluating the process of SSCs differentiation in organ culture and the fact that cell culture on a two-dimensional substrate cannot create niche-like conditions for SSCs, the use of T-ECM-based 3D substrates was considered with the goal of preserving the natural morphology of cells in vivo.

Study design, size, duration

In this study, the effects of hybrid (alginate-gelatin) and composite (T-ECM-alginate-gelatin) printed scaffolds on the proliferation (two weeks) and differentiation (three weeks) of murine SSCs were investigated at the molecular, cellular, morphological, and functional levels.

Participants/materials, setting, methods

A hypertonic solution-triton was used to decellularize testicular tissue. The extracted ECM was employed as a bio-ink to print in combination with alginate-gelatin. Pre-meiotic and post-meiotic cells in the studied groups (as testicular suspension and co-culture with Sertoli cells) were validated by real-time PCR, flow cytometry, and immunocytochemistry. Morphology of cells was evaluated using TEM, H&E, toluidine blue, and Giemsa staining. The ability of Leydig and Sertoli cells to secrete hormones determined their functionality.

Main results and the role of chance

The results demonstrated that decellularization of testicular tissue fragments was successful, with cellular debris effectively eliminated while ECM components were retained. High cell viability, colonization, and enhanced expression of Plzf, Id4, and Gfra1 pre-meiotic markers in cultured testicular cells on ECM-enriched scaffolds were used to determine the effects of proliferation (group 4) (P ≤ 0.05). Also, after 3 weeks of culture in the differentiation medium, cell viability and expression of Sycp3, Acr and Prm1 markers in group 4 were higher than in other groups (P ≤ 0.05). The structure of these cells in group 4 was remarkably comparable to mature sperm with a specialized tail structure, according to morphological analysis. The release of testosterone and inhibin B by Leydig and Sertoli cells was also verified by the hormonal assay.

Limitations, reasons for caution

We were unable to assess epigenetic alterations and the fertility of mature sperm obtained in this system due to the delay in preparing the material for culture, the long set-up time, the fabrication of hydrogel scaffolds using the 3D printing approach, and the long-term culture in the laboratory.

Wider implications of the findings

This research demonstrated the rapid generation of morphologically normal sperm in the lab and the simple extraction of mature sperm from a T-ECM-based printing system, paving the path for new infertility and sperm production treatments in azoospermic patients and cancer survivors.

Trial registration number

N/A

Effects of hydrostatic pressure on mouse sperm

OBJECTIVES

The objective of this study was to investigate the abnormalities in sperm after exposure to hydrostatic pressure.

BACKGROUND

Hydrostatic pressure acting on the cells is one of the fundamental environmental mechanical forces. Disorders of relationship between the cells and this mechanical force, such as when pressure varies beyond physiological limits, can lead to disease or pathological states. Sperm exposed to different range of hydrostatic pressure within male reproductive system and after entering the female reproductive system.

METHODS

Sexually mature male NMRI mice, 8-12 weeks-old were sperm donors. Sperms were separated from the caudal epididymis and maintained in Ham's F-10 culture medium supplemented with 10 % FBS and divided into control and treatments. Sperm suspensions in the treatments were placed within pressure chamber and were subjected to increased hydrostatic pressure of 25, 50 and 100 mmHg (treatment I, II and III) above atmospheric pressure for 2 and 4 h. Sperm viability, motility, morphology, DNA integrity and fertilizing ability were assessed and compared with control.

RESULTS

Results showed that hydrostatic pressure dependent on ranges and time manner reduced sperm quality due to adverse effect on viability, motility , morphology, DNA integrity and fertilizing ability in all of treatments, especially after 4h (p<0.05).

CONCLUSION

Our data revealed hydrostatic pressure reduces sperm quality as a consequence of adverse effects on sperm parameters and may cause male infertility or subfertility (Tab. 5, Ref. 5).

Increased receptor for advanced glycation end products in spermatozoa of diabetic men and its association with sperm nuclear DNA fragmentation

Although the majority of patients with diabetes have disorders in sexual function, associations between diabetes mellitus and sperm function at the molecular level are largely unknown. As receptor for advanced glycation end products plays a key role in many diabetic complications, we hypothesised that it may be involved in sperm nuclear DNA fragmentation. RAGE levels were determined using ELISA and western blot analysis in sperm samples from 32 diabetic and 35 nondiabetic men. Sperm DNA fragmentation was assessed using TUNEL assay. Diabetic men had significantly higher mean levels of RAGE protein (P < 0.001) and DNA fragmentation (P < 0.001) in spermatozoa. Sperm RAGE was directly correlated to sperm DNA fragmentation in diabetic men (r = 0.81, P < 0.001). The high positive correlation between RAGE levels and nuclear DNA fragmentation in spermatozoa of diabetic men suggests a central role of RAGE in disturbances in sexual function of diabetic men.

Relationship between advanced glycation end products and increased lipid peroxidation in semen of diabetic men

AIMS

Majority of diabetic male patients have disturbances in their reproductive systems. However, the mechanisms underlying these disturbances are largely unknown. Since advanced glycation end products (AGE) have a key role in oxidative stress and cell damage in diabetic complications, we hypothesize that AGEs may be involved sperm lipid peroxidation.

METHODS

total AGEs in seminal plasma of 32 diabetic and 35 non-diabetic men was determined by spectrofluorimetric method and carboxy methyl lysine (CML) level was assayed using ELISA. Contents of lipid peroxidation in sperm and seminal plasma were determined by thiobarbituric acid reaction. Total antioxidant capacity (TAC) was measured by a colorimetric assay.

RESULTS

total AGEs were found significantly higher in seminal plasma of diabetic men than non-diabetic group (p<0.001) whereas no significant differences in seminal plasma CML values between two groups was observed. Moreover, sperm and seminal plasma lipid peroxidation were significantly higher in diabetic subjects than non-diabetic men and a significantly lower TAC was detected in diabetic group compare to non-diabetics.

CONCLUSIONS

these results showed an increment in AGEs in seminal plasma of diabetic subjects and may suggest a key role for glycation process and increased oxidative stress in reproductive system dysfunction.

L-carnitine level in seminal plasma of fertile and infertile men

BACKGROUND

To determine any correlation between infertility and semen quality with concentrations of L-carnitine in human seminal plasma.

METHODS

This case-control study performed in Fatemieh Hospital in Hamadan, Iran. Seminal plasma of 72 infertile men and 80 men with proved fertility as a control group was investigated and L-carnitine level was determined using UV enzymatic test at 340 nm.

RESULTS

The concentration of L-carnitine was significantly lower in the infertile group compared with control group (80.59±56.43 mg/l versus 108.43±42.26 mg/l; P= 0.0009). There was also a statistically significant positive correlation between seminal plasma L-carnitine concentration, total sperm count, and the percentage of motile sperm (P= 0.0009, and P= 0.0000, respectively).

CONCLUSION

These finding suggest that the determination of seminal plasma L-carnitine level may be a useful test in evaluation of male infertility.

The complete amino acid sequence of the pathogenesis-related (PR2) protein induced in chemically stressed bean leaves

We have established the complete sequence of the 155 amino acid residues of the pathogenesis-related protein PR2 accumulating in bean leaves treated with a mercuric chloride solution. Bean PR2 whose biological function remains to be elucidated, represents a structurally unfamiliar protein in which sequence arginine, cysteine, methionine and tryptophan residues are missing. This sequence is identical to that of bean PvPR1.

Clostridium difficile toxin B: characterization and sequence of three peptides

The cytotoxin, also named toxin B, was isolated from a toxigenic strain of Clostridium difficile, purified to homogeneity and partially characterized. The purification procedure included ultrafiltration followed by anion-exchange chromatography. We noticed that a non-specific nucleic material eluted with the protein during the purification. The presence of these nucleic acids appeared to be important for the toxic activity of the protein. Some characteristics of the cytotoxin were examined, especially the amino acid composition and the sequence of three tryptic fragments.

Amino acid composition and proteolytic generated domains of higher plant tubulin

The molecular architecture of tubulin from higher plant remains unknown. In this report we have made an attempt to identify higher plant tubulin domains using total and limited proteolysis of Haemanthus endosperm tubulin. The tubulin was previously purified and characterized (Picquot and Lambert 1988). The amino acid composition revealed a high content of basic residues, such as arginine and lysine. Tubulin domains were probed by tryptic and chymotryptic cleavage and analyzed by immunoblotting using specific monoclonal antibodies against alpha or beta subunits. These data shed light on specific properties of the higher plant tubulin.

Isolation and structure of a pseudopeptide gamma-L-glutamyl-L-aspartic acid from Datura stramonium that impairs learning retention in mice

Datura stramonium contains a compound that impairs learning retention in mice. It has been purified to homogeneity and its structure has been established as that of a gamma-L-glutamyl-L-aspartate. The biological activity of this pseudodipeptide has been found to be identical with that of the corresponding synthetic one. It has also been compared to those of various synthetic di- and tripeptides containing L- and/or D-enantiomers of the constitutive amino acids. The results show that the activity is associated with a peptidic structure containing only one type of enantiomer.

gamma-L-glutamyl-L-aspartate induces specific deficits in long-term memory and inhibits [3H]glutamate binding on hippocampal membranes

gamma-L-Glutamyl-L-aspartic acid (gamma-LGLA) has been isolated from Datura stramonium; its structure has been determined and it was then synthesized. In male Swiss mice intraperitoneal administration of the natural peptide (125 nmol/kg) or of the synthetic peptide (25-2500 nmol/kg) 24 h after acquisition of a Y-maze avoidance task induced a dose-dependent deficit in retention performance 48 h later. gamma-LGLA had no effect on locomotor activity or emotional reactivity at the doses used. Separate or simultaneous administration of aspartate or glutamate (each at 250 nmol/kg) had no effect on learning retention, indicating that deficit induced by gamma-LGLA was specific to the peptide. gamma-LGLA impaired learning acquisition in a time-dependent manner when administered from 3 min to 24 h post-training, but had no effect when administered 3 days following acquisition. gamma-LGLA administered just after the training session did not affect retention performance during the first 3 h, but suppressed the retention improvement observed in control animals from 6 to 24 h after acquisition; this deficit was still evident 7 days after the treatment. gamma-LGLA partially inhibited L-[3H]glutamate binding on crude hippocampal or striatal membrane preparations; this inhibition was not observed on cerebellar membrane preparations. These results suggest a specific action of gamma-LGLA on excitatory amino acid systems which may be responsible for its effects on learning retention.

Amino acid sequence of the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit from Euglena

The amino acid sequence of the ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) small subunit (SSU) from Euglena has been established by alignment of the sequence of peptides obtained by cleavage with chymotrypsin, trypsin, Staphylococcus aureus protease or formic acid. The Euglena SSU has 138 amino acids and thus represents longest SSU sequence described so far. Homology is only 41% with cyanobacteria SSU and about 51% with higher plant SSU, whereas it is around 75% between higher plants. The largest homologous portion between all the known SSU sequences is localized in the second half and covers about 20 amino acids. The phylogenetic tree based on known SSU sequences has been established and the rate of amino acid substitution for SSU is estimated to be about 1.35×10(-9) per year and per site. Despite heterogeneity in amino acid sequence, we found that the overall secondary structure is fairly well conserved.

The complete amino acid sequence of cytoplasmic aspartyl-tRNA synthetase from Saccharomyces cerevisiae

The crystallizable cytoplasmic aspartyl-tRNA synthetase from Saccharomyces cerevisiae is a dimer made up of identical subunits (Mr 63 000). Its primary structure was established using peptide sequences from four different digests of the native and citraconylated enzyme with trypsin, cyanogen bromide and staphylococcal protease. The oligonucleotide sequence of the structural gene was used as a template for the final alignment of the various peptides in the correct order.

A home-made solid-phase sequencer operating at the nanomole level

The building and functioning of a fully automated solid-phase sequencer is described. The peptide is coupled via its alpha-carboxyl end to activated glass beads and successively reacted with Chang's and Edman's reagents. All operations are electronically controlled by the automated programmer. All components necessary to build the machine are commercially available. This sequencer has been used at a nanomole level in the final phase of a protein sequence determination. The overall cost as well as the sensitivity and efficiency of the final product compare favourably to those of commercial machines.