CaMKⅡ mediates cadmium induced apoptosis in rat primary osteoblasts through MAPK activation and endoplasmic reticulum stress

Melatonin attenuates cadmium-induced ovulatory dysfunction by suppressing endoplasmic reticulum stress and cell apoptosis

BACKGROUND

Increasing evidence demonstrate that cadmium (Cd) has adverse effects on the mammalian reproductive system. However, the mechanisms underlying the effects of Cd on ovarian function and the strategies to reverse these effects have not been fully elucidated.

METHODS

In this study, 60 CD-1 mice were divided into four groups (control, melatonin, Cd, Cd with melatonin). During the treatment for 14 days, body weight was measured every 2 days. After the treatment, ovaries were isolated and weighted to observe the morphological and biological characteristics. Statistical analyses were performed using one-way ANOVA followed by Fisher's-multiple range test or chi-squared test, A P value < 0.05 indicated statistical significance.

RESULTS

We observed that Cd exposure induced ovulatory dysfunction, demonstrated by the reduced number of ovulated oocytes numbers in the Cd group. However, this endoplasmic reticulum (ER) pathway was activated in the Cd-exposed ovaries and the expression of GRP78, ATF4, CHOP, and p-JNK was upregulated, which was reversed by treatment with melatonin. Furthermore, we found that melatonin inhibited Cd-induced activation of cleaved caspase-3, restored the ratio of Bax/Bcl-2, and ultimately decreased the apoptosis of granular cells as detected by TUNEL staining.

CONCLUSION

Collectively, our findings reveal that melatonin attenuated Cd-induced ovulation dysfunction and cell apoptosis by inhibiting the activation of the ER pathway. Thus, melatonin can be a potential agent to protect mammalian ovaries against Cd toxicity.

The Multi-Functional Calcium/Calmodulin Stimulated Protein Kinase (CaMK) Family: Emerging Targets for Anti-Cancer Therapeutic Intervention

The importance of Ca²⁺ signalling in key events of cancer cell function and tumour progression, such as proliferation, migration, invasion and survival, has recently begun to be appreciated. Many cellular Ca²⁺-stimulated signalling cascades utilise the intermediate, calmodulin (CaM). The Ca²⁺/CaM complex binds and activates a variety of enzymes, including members of the multifunctional Ca²⁺/calmodulin-stimulated protein kinase (CaMK) family. These enzymes control a broad range of cancer-related functions in a multitude of tumour types. Herein, we explore the cancer-related functions of these kinases and discuss their potential as targets for therapeutic intervention.

MicroRNA Expression Analysis of Naked Silkworms

The silk gland (SG) is characterized by the synthesis and secretion of silk protein in the economically important silkworm, Bombyx mori L. (Lepidoptera: Bombycidae). Nd and Nd-s are two fibroin-secretion-deficient silkworm mutants. MicroRNA (miRNA) plays an important role in many biological processes, such as cell proliferation, differentiation, and apoptosis. Using the Dazao silkworm as a control, we explored the miRNA expression profiles in the SGs of u02 (Nd) and u05 (Nd-s) to reveal the potential functions of miRNAs in silk protein expression and SG development. Here, we sequenced small RNA libraries made from the whole SGs of three strains. There are 260, 236, and 233 known miRNAs and 20, 18, and 18 potential new miRNAs identified from Dazao, u02, and u05, respectively. Fifty-three miRNAs are differentially expressed between Dazao and u02, 51 between Dazao and u05, and 16 between u02 and u05. Gene ontology/KEGG analyses show that most of the predicted target genes of differentially expressed miRNAs were assigned to functional categories involved in cell proliferation, organ development, and cellular compartment structures. The miRNA expression profile of naked silkworms will pave the way for the understanding of SG development and the regulation of silk protein expression.