Technology Insight: small, noncoding RNA molecules as tools to study and treat endocrine diseases

MicroRNA-16 represses granulosa cell proliferation in polycystic ovarian syndrome through inhibition of the PI3K/Akt pathway by downregulation of Apelin13

This study aimed to uncover the specific role of micro RNA-16 (miR-16) in granulosa cell function in polycystic ovarian syndrome (PCOS). After sample collection, the expression levels of miR-16 and Apelin13 in the granulosa cells of PCOS patients and controls were determined. Subsequently, miR-16 mimic, miR-16 inhibitor, pcDNA3.1-Apelin13, sh-Apelin13, and their corresponding negative controls were transfected into granulosa cell lines (KGN and SVOG) to monitor alterations in miR-16 expression, Apelin13, and PI3K/Akt signalling pathway-related proteins (p-Akt and Akt). MTT assay was used to detect cell viability, clone formation assay to detect cell proliferation, and flow cytometry to detect cell apoptosis rate. In addition, a luciferase assay was performed to test the targeting relationship between miR-16 and Apelin13. After miR-16 overexpression or Apelin13 knockdown was achieved in granulosa cells, granulosa cell proliferation was suppressed and cell apoptosis was enhanced. Additionally, Apelin13 is a potential target of miR-16. Functionally, overexpression of Apelin13 could partly reverse the effect of miR-16 overexpression on granulosa cell proliferation and apoptosis. Moreover, inhibits granulosa cell proliferation and enhances blocking the PI3K/Akt pathway by suppressing Apelin13. Our study revealed miR-16 regulates Apelin13 to mediate the PI3K/Akt signalling pathway and, thereby mediates PCOS progression.

Synaptic Plasticity Dysfunctions in the Pathophysiology of 22q11 Deletion Syndrome: Is There a Role for Astrocytes?

The 22q11 deletion syndrome (DS) is the most common microdeletion syndrome in humans and gives a high probability of developing psychiatric disorders. Synaptic and neuronal malfunctions appear to be at the core of the symptoms presented by patients. In fact, it has long been suggested that the behavioural and cognitive impairments observed in 22q11DS are probably due to alterations in the mechanisms regulating synaptic function and plasticity. Often, synaptic changes are related to structural and functional changes observed in patients with cognitive dysfunctions, therefore suggesting that synaptic plasticity has a crucial role in the pathophysiology of the syndrome. Most interestingly, among the genes deleted in 22q11DS, six encode for mitochondrial proteins that, in mouse models, are highly expressed just after birth, when active synaptogenesis occurs, therefore indicating that mitochondrial processes are strictly related to synapse formation and maintenance of a correct synaptic signalling. Because correct synaptic functioning, not only requires correct neuronal function and metabolism, but also needs the active contribution of astrocytes, we summarize in this review recent studies showing the involvement of synaptic plasticity in the pathophysiology of 22q11DS and we discuss the relevance of mitochondria in these processes and the possible involvement of astrocytes.

A reusable sensor for the label-free detection of specific oligonucleotides by surface plasmon fluorescence spectroscopy

The development of a reusable molecular beacon (MB)-based sensor for the label-free detection of specific oligonucleotides using surface plasmon fluorescence spectroscopy (SPFS) as the readout method is described. The MBs are chemisorbed at planar gold surfaces serving as fluorescence quenching units. Target oligonucleotides of 24 bases can be detected within a few minutes at high single-mismatch discrimination rates.

Co-transfection and tandem transfection of HEK293A cells for overexpression and RNAi experiments

pIRES2-EGFP was employed and a non-target shRNA expressing plasmid was constructed to simulate overexpression and RNAi (RNA interference) experiments. Transfection of pIRES2-EGFP into HEK293A cells by cationic lipids VigoFect demonstrated that transfection efficiency increased in a dose-dependent manner with amount of DNA plasmid used, and optimal transfection time and cell density should be identified to reach a compromise of higher transfection efficiency and lower toxicity. Co-transfection experiments indicated that the two co-transfected plasmids were equivalently delivered into the same cells, and the co-transfection efficiency was rarely affected by cell density and proportion of the two plasmids. However, plasmid-receipted cells seemed indisposed to accept plasmid again during the second transfection, and very low co-transfection efficiency was observed in tandem transfection.

Specificity of insulin signalling in human skeletal muscle as revealed by small interfering RNA

Insulin action on metabolically active tissues is a complex process involving positive and negative feedback regulation to control whole body glucose homeostasis. At the cellular level, glucose and lipid metabolism, as well as protein synthesis, are controlled through canonical insulin signalling cascades. The discovery of small interfering RNA (siRNA) allows for the molecular dissection of critical components of the regulation of metabolic and gene regulatory events in insulin-sensitive tissues. The application of siRNA to tissues of human origin allows for the molecular dissection of the mechanism(s) regulating glucose and lipid metabolism. Penetration of the pathways controlling insulin action in human tissue may aid in discovery efforts to develop diabetes prevention and treatment strategies. This review will focus on the use of siRNA to validate critical regulators controlling insulin action in human skeletal muscle, a key organ important for the control of whole body insulin-mediated glucose uptake and metabolism.

Small interfering RNA therapy in cancer: mechanism, potential targets, and clinical applications

BACKGROUND

Small interfering RNA (siRNA) has become a powerful tool in knocking down or silencing gene expression in most cells. siRNA-based therapy has shown great promise for many diseases such as cancer. Major targets for siRNA therapy include oncogenes and genes that are involved in angiogenesis, metastasis, survival, antiapoptosis and resistance to chemotherapy.

OBJECTIVES

This review briefly summarizes current advances in siRNA therapy and clinical applications in cancers, especially in pancreatic cancer.

METHODS

This review article covers several aspects of siRNA therapy in cancer, which include the types of siRNA, the delivery systems for siRNA, and the major targets for siRNA therapy. Specific attention is given to siRNA in pancreatic cancer, which is our main research focus.

RESULTS/CONCLUSION

siRNA can be introduced into the cells by using either chemically synthesized siRNA oligonucleotides (oligos), or vector-based siRNA (shRNA), which allows long lasting and more stable gene silencing. Nanoparticles and liposomes are commonly used carriers, delivering the siRNA with better transfection efficiency and protecting it from degradation. In combination with standard chemotherapy, siRNA therapy can also reduce the chemoresistance of certain cancers, demonstrating the potential of siRNA therapy for treating many malignant diseases. This review will provide valuable information for clinicians and researchers who want to recognize the newest endeavors within this field and identify possible lines of investigation in cancer.