Oncofertility care for newly diagnosed girls with cancer in a national pediatric oncology setting, the first full year experience from the Princess Máxima Center, the PEARL study.

BACKGROUND: Childhood cancer patients often remain uninformed regarding their potential risk of gonadal damage. In our hospital we introduced a five step standard oncofertility care plan for all newly diagnosed female patients aiming to identify, inform and triage 100% of patients and counsel 100% of patients at high risk (HR) of gonadal damage. This observational retrospective study (PEARL study) evaluated the use of this standard oncofertility care plan in the first full year in a national cohort. METHODS: The steps consist of 1)timely (preferably before start of gonadotoxic treatment) identification of all new patients, 2)triage of gonadal damage risk using a standardized gonadal damage risk stratification tool, 3)informing all patients and families, 4)counseling of a selected subset of girls, and 5) fertility preservation including ovarian tissue cryopreservation (OTC) in HR patients using amended Edinburgh criteria. A survey of the medical records of all girls newly diagnosed with cancer the first year (1-1-2019 until 31-12-2019) was conducted. RESULTS: Of 261 girls, 228 (87.4%) were timely identified and triaged. Triage resulted in 151 (66%) low(LR), 32 (14%) intermediate(IR) and 45 (20%) high risk(HR) patients. Ninety-nine families were documented to be timely informed regarding gonadal damage risk. In total, 35 girls (5 LR, 5 IR, 25 HR) were counseled by an oncofertility expert. 16/25 HR patients underwent fertility preservation (1 ovariopexy + OTC, oocyte cryopreservation (1 with and 1 without OTC) and 13 OTC). Fertility preservation did not lead to complications or delay of cancer treatment in any patient. CONCLUSION: We timely identified and triaged most girls (88%) with cancer with a high risk of gonadal damage to be counseled for fertility preservation. We aim to optimize the oncofertility care plan and the standardized gonadal damage risk stratification tool based on this experience and these may be of value to other pediatric oncology centers.

Open epididymal spermatozoa aspiration for obstructive azoospermia.

In men suffering from obstructive azoospermia (OA), surgical sperm retrieval (SR) can be performed for use with intracytoplasmic sperm injection (ICSI). Several techniques of surgical SR exist, with various results. In our facility, we have developed the open epididymal spermatozoa aspiration (OESA) procedure. The aim of this study was to report on the sperm retrieval rate (SRR), reproductive outcome and neonatal outcome of OESA followed by ICSI. In addition, we have investigated possible predictors of successful SR and clinical pregnancy. A total of 231 men who were treated with OESA were included in this retrospective analysis, together with their female partners. We found an overall SRR of 76.6%. Serum FSH was a significant negative predictor of successful SR (odds ratio 0.87; 95% CI 0.78-0.98; p = 0.021). Overall cumulative pregnancy rate was 50.8%. Higher age (odds ratio 0.90; p < 0.001) and frozen vs. fresh embryo transfer (odds ratio 0.56; p = 0.004) were negatively associated with clinical pregnancy in multivariable analysis. Reproductive and neonatal outcomes did not differ according to obstruction cause. We conclude that OESA is a reliable and safe method for surgical SR in men suffering from OA.

Semen cryopreservation and usage rate for assisted reproductive technology in 898 men with cancer.

An undesired side effect of cancer treatment is potential subfertility or infertility. Timely cryopreservation of semen is the best modality to ensure fertility. This retrospective data analysis established the usage rate of cryopreserved semen from cancer patients. Pubertal and post-pubertal patients who could become infertile as a result of cancer (treatment) were offered the option to cryopreserve semen prior to treatment. Of the 898 patients who cryopreserved their semen in our hospital, 96 (10.7%) used this for assisted reproductive technology. The live birth rates for intrauterine insemination, in-vitro fertilization, intracytoplasmic sperm injection and cryopreserved embryo transfer were 13%, 29%, 32% and 17%, respectively. Of all couples involved, 77% achieved parenthood, i.e. 60 of the 78 patients (with complete follow-up) fathered at least one child.

Central melanocortins regulate the motivation for sucrose reward.

The role of the melanocortin (MC) system in feeding behavior is well established. Food intake is potently suppressed by central infusion of the MC 3/4 receptor agonist α-melanocyte stimulating hormone (α-MSH), whereas the MC 3/4 receptor inverse-agonist Agouti Related Peptide (AGRP) has the opposite effect. MC receptors are widely expressed in both hypothalamic and extra-hypothalamic brain regions, including nuclei involved in food reward and motivation, such as the nucleus accumbens (NAc) and the ventral tegmental area. This suggests that MCs modulate motivational aspects of food intake. To test this hypothesis, rats were injected intracerebroventricularly with α-MSH or AGRP and their motivation for sucrose was tested under a progressive ratio schedule of reinforcement. Food motivated behavior was dose-dependently decreased by α-MSH. Conversely, AGRP increased responding for sucrose, an effect that was blocked by pretreatment with the dopamine receptor antagonist α-flupenthixol. In contrast to progressive ratio responding, free intake of sucrose remained unaltered upon α-MSH or AGRP infusion. In addition, we investigated whether the effects of α-MSH and AGRP on food motivation were mediated by the NAc shell. In situ hybridization of MC3 and MC4 receptor expression confirmed that the MC4 receptor was expressed throughout the NAc, and injection of α-MSH and AGRP into the NAc shell caused a decrease and an increase in motivation for sucrose, respectively. These data show that the motivation for palatable food is modulated by MC4 receptors in the NAc shell, and demonstrate cross-talk between the MC and dopamine system in the modulation of food motivation.

Cannabinoid, melanocortin and opioid receptor expression on DRD1 and DRD2 subpopulations in rat striatum.

The striatum harbors two neuronal populations that enable action selection. One population represents the striatonigral pathway, expresses the dopamine receptor D1 (DRD1) and promotes the execution of motor programs, while the other population represents the striatopallidal pathway, expresses the dopamine receptor D2 (DRD2) and suppresses voluntary activity. The two populations integrate distinct sensorimotor, cognitive, and emotional information streams and their combined activity enables the selection of adaptive behaviors. Characterization of these populations is critical to the understanding of their role in action selection, because it aids the identification of the molecular mechanisms that separate them. To that end, we used fluorescent in situ hybridization to quantify the percentage of striatal cells that (co)express dopaminergic receptors and receptors of the cannabinoid, melanocortin or opioid neurotransmitters systems. Our main findings are that the cannabinoid 1 receptor is equally expressed on both populations with a gradient from dorsal to ventral striatum, that the opioid receptors have a preference for expression with either the DRD1 or DRD2 and that the melanocortin 4 receptor (MC4R) is predominantly expressed in ventral parts of the striatum. In addition, we find that the level of MC4R expression determines its localization to either the DRD1 or the DRD2 population. Thereby, we provide insight into the sensitivity of the two dopaminoceptive populations to these neurotransmitters and progress the understanding of the mechanisms that enable action selection.

A tail-anchored myotonic dystrophy protein kinase isoform induces perinuclear clustering of mitochondria, autophagy, and apoptosis.

BACKGROUND: Studies on the myotonic dystrophy protein kinase (DMPK) gene and gene products have thus far mainly concentrated on the fate of length mutation in the (CTG)n repeat at the DNA level and consequences of repeat expansion at the RNA level in DM1 patients and disease models. Surprisingly little is known about the function of DMPK protein products. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrate here that transient expression of one major protein product of the human gene, the hDMPK A isoform with a long tail anchor, results in mitochondrial fragmentation and clustering in the perinuclear region. Clustering occurred in a variety of cell types and was enhanced by an intact tubulin cytoskeleton. In addition to morphomechanical changes, hDMPK A expression induces physiological changes like loss of mitochondrial membrane potential, increased autophagy activity, and leakage of cytochrome c from the mitochondrial intermembrane space accompanied by apoptosis. Truncation analysis using YFP-hDMPK A fusion constructs revealed that the protein's tail domain was necessary and sufficient to evoke mitochondrial clustering behavior. CONCLUSION/SIGNIFICANCE: Our data suggest that the expression level of the DMPK A isoform needs to be tightly controlled in cells where the hDMPK gene is expressed. We speculate that aberrant splice isoform expression might be a codetermining factor in manifestation of specific DM1 features in patients.

DMPK protein isoforms are differentially expressed in myogenic and neural cell lineages.

Myotonic dystrophy type 1 (DM1) is a neuromuscular disorder caused by an unstable (CTG . CAG)n segment in the 3' untranslated region of the myotonic dystrophy protein kinase (DMPK) gene. It is commonly accepted that DMPK mRNA-based toxicity is the main contributor to DM1 manifestations; however, not much is known about the significance of the DMPK protein. To appreciate its normal and possible pathobiological role, we analyzed the patterns of DMPK splice isoform expression in mouse tissues. Long membrane-anchored DMPK dominated in heart, diaphragm, and skeletal muscle, whereas short cytosolic isoforms were highly expressed in bladder and stomach. Both isoform types were present in diverse brain regions. DMPK protein was also detectable in cultured myoblasts, myotubes, cortical astrocytes, and related cell lines of neural or muscle origin, but not in hippocampal neurons. This work identifies DMPK as a kinase with pronounced expression in diverse muscle and neural tissues that are affected in DM1.

Coiled-coil interactions modulate multimerization, mitochondrial binding and kinase activity of myotonic dystrophy protein kinase splice isoforms.

The myotonic dystrophy protein kinase polypeptide repertoire in mice and humans consists of six different splice isoforms that vary in the nature of their C-terminal tails and in the presence or absence of an internal Val-Ser-Gly-Gly-Gly motif. Here, we demonstrate that myotonic dystrophy protein kinase isoforms exist in high-molecular-weight complexes controlled by homo- and heteromultimerization. This multimerization is mediated by coiled-coil interactions in the tail-proximal domain and occurs independently of alternatively spliced protein segments or myotonic dystrophy protein kinase activity. Complex formation was impaired in myotonic dystrophy protein kinase mutants in which three leucines at positions a and d in the coiled-coil heptad repeats were mutated to glycines. These coiled-coil mutants were still capable of autophosphorylation and transphosphorylation of peptides, but the rates of their kinase activities were significantly lowered. Moreover, phosphorylation of the natural myotonic dystrophy protein kinase substrate, myosin phosphatase targeting subunit, was preserved, even though binding of the myotonic dystrophy protein kinase to the myosin phosphatase targeting subunit was strongly reduced. Furthermore, the association of myotonic dystrophy protein kinase isoform C to the mitochondrial outer membrane was weakened when the coiled-coil interaction was perturbed. Our findings indicate that the coiled-coil domain modulates myotonic dystrophy protein kinase multimerization, substrate binding, kinase activity and subcellular localization characteristics.

Divergent mitochondrial and endoplasmic reticulum association of DMPK splice isoforms depends on unique sequence arrangements in tail anchors.

Myotonic dystrophy protein kinase (DMPK) is a Ser/Thr-type protein kinase with unknown function, originally identified as the product of the gene that is mutated by triplet repeat expansion in patients with myotonic dystrophy type 1 (DM1). Alternative splicing of DMPK transcripts results in multiple protein isoforms carrying distinct C termini. Here, we demonstrate by expressing individual DMPKs in various cell types, including C(2)C(12) and DMPK(-/-) myoblast cells, that unique sequence arrangements in these tails control the specificity of anchoring into intracellular membranes. Mouse DMPK A and C were found to associate specifically with either the endoplasmic reticulum (ER) or the mitochondrial outer membrane, whereas the corresponding human DMPK A and C proteins both localized to mitochondria. Expression of mouse and human DMPK A-but not C-isoforms in mammalian cells caused clustering of ER or mitochondria. Membrane association of DMPK isoforms was resistant to alkaline conditions, and mutagenesis analysis showed that proper anchoring was differentially dependent on basic residues flanking putative transmembrane domains, demonstrating that DMPK tails form unique tail anchors. This work identifies DMPK as the first kinase in the class of tail-anchored proteins, with a possible role in organelle distribution and dynamics.