Limited efficacy of somatic cell lysis buffer to purify laboratory mouse sperm

Avian sperm-borne RNAs: optimisation of a new isolation protocol

1. Sperm-borne RNAs are involved in sperm and embryonic protein translation, the regulation of early development and the epigenetic inheritance of the paternal phenotype. Sperm-borne RNA purification protocols generally include a cell purification stage to discard contamination by somatic cells. In avian species, no protocol is currently available to isolate all the populations composing sperm-borne RNAs.2. This study evaluated the presence of somatic cells in semen samples of chickens and quails using visual examination after fluorescent nuclei staining. The efficiency of somatic cell lysis buffer (SCLB) on chicken liver cells and its impacts on chicken sperm cell integrity was explored. Three different approaches were tested to isolate RNA: two developed for mammalian sperm cells and a commercial kit for somatic cells. The efficiency and reliability of each approach was determined based on RNA quality and purity. Eventually, the presence of miRNA and mRNA in purified avian sperm-borne RNAs was investigated by RT-(q)PCR.3. No somatic cells were found in chicken and quail semen. The SCLB totally lysed chicken liver cells but also induced sperm cell necrosis. Consequently, this treatment wasn't performed on samples prior to RNA isolation. Among the tested RNA purification protocols, the commercial one was the least variable and isolated RNA with the highest purity levels. No DNA contamination was observed. Furthermore, the samples contained miRNA and mRNA already known as present in mammalian sperm cells (gga-miR-100-5p, gga-miR-191-5p, GAPDH and PLCZ1), but mRNAs associated with leucocytes (CD4) and Sertoli cells (SOX4, CLDN11) were not detected. This protocol was successfully applied to quail sperm cells.4. Altogether, the study reveals that it is unnecessary to pre-treat samples to remove somatic cell contamination before RNA purification and successfully describes an isolation protocol for sperm-borne RNAs, including small non-coding and long coding RNAs, in two distinct avian species highly valuable as biological models.

Metabolomic profiling reveals correlations between spermiogram parameters and the metabolites present in human spermatozoa and seminal plasma

In 50% of all infertility cases, the male is subfertile or infertile, however, the underlying mechanisms are often unknown. Even when assisted reproductive procedures such as in vitro fertilization and intracytoplasmic sperm injection are performed, the causes of male factor infertility frequently remain elusive. Since the overall activity of cells is closely linked to their metabolic capacity, we analyzed a panel of 180 metabolites in human sperm and seminal plasma and elucidated their associations with spermiogram parameters. Therefore, metabolites from a group of 20 healthy donors were investigated using a targeted LC-MS/MS approach. The correlation analyses of the amino acids, biogenic amines, acylcarnitines, lysophosphatidylcholines, phosphatidylcholines, sphingomyelins and sugars from sperm and seminal plasma with standard spermiogram parameters revealed that metabolites in sperm are closely related to sperm motility, whereas those in seminal plasma are closely related to sperm concentration and morphology. This study provides essential insights into the metabolome of human sperm and seminal plasma and its associations with sperm functions. This metabolomics technique could be a promising screening tool to detect the factors of male infertility in cases where the cause of infertility is unclear.