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Nucleoside diphosphate kinase (NDK), which has the same sequence as oncoprotein (OP) in humans, can induce nucleoside triphosphates in DNA replication by maintenance of the deoxynucleotide triphosphate (dNTP’s) and is known to be regulated by viral infection in the shrimp Litopenaeus vannamei. This paper describes the relationship between NDK and white spot syndrome virus (WSSV) infection. The recombinant NDK was produced by a prokaryotic expression system. WSSV copy numbers and mRNA levels of IE1 and VP28 were significantly increased in shrimp injected with recombinant NDK at 72 h after WSSV infection. After synthesizing dsRNA-NDK and confirming the efficacy of NDK silencing, we recorded the cumulative mortality of WSSV-infected shrimp injected with NDK and dsRNA-NDK. A comparison between the results demonstrated that silencing NDK delayed the death of shrimps. These findings indicate that NDK has an important role influencing the replication of WSSV replication in shrimp. Furthermore, NDK may have potential target as a new therapeutic strategy against WSSV infection in shrimp.

Osteoclasts are large multinucleated cells responsible for bone resorption. Excessive inflammatory activation of osteoclasts leads to bony erosions, which are the hallmark of several diseases such as rheumatoid arthritis (RA). Salt-inducible kinases (SIK) constitute a subfamily of kinases comprising three members (SIK1, -2, and -3). Inhibition of SIK kinase activity induces an anti-inflammatory phenotype in macrophages. Since osteoclasts originate from precursors of macrophage origin, we hypothesized a role of SIK in osteoclastogenesis. We analyzed SIK1, -2 and -3 expression and function in osteoclast differentiation using the mouse macrophage cell line RAW264.7 and bone marrow-derived macrophages (BMM). We show that all three SIK are expressed in fully differentiated osteoclasts and that in BMM-derived osteoclasts there is an increased expression of SIK1 and SIK3 proteins. Interestingly, the pan-SIK inhibitor HG-9-91-01 significantly inhibited osteoclastogenesis by dose dependently reducing osteoclast differentiation markers (i.e. CathepsinK, MMP-9 and TRAP) and bone resorbing activity. Analysis of the signaling pathways activated by RANKL in RAW cells showed that SIK inhibitors did not affect RANKL-induced ERK1/2, JNK, p38 or NF-κB activation, but induced a significant downregulation in c-Fos and NFATc1 protein levels, the two main transcription factors involved in the regulation of osteoclast-specific genes. Moreover, SIK inhibition partially increased the proteasome-mediated degradation of c-Fos. SIK2 and SIK3 knockout RAW cells were generated by the CRISPR/Cas9 approach. SIK2 KO and, to a lesser extent, SIK3 KO recapitulated the effect of SIK small molecule inhibitor, thus confirming the specificity of the effect of SIK inhibition on the reduction of osteoclastogenesis. Overall, our results support the notion that the SIK signaling pathway plays a significant role among the check-points controlling osteoclastogenesis. SIK kinase inhibitors could thus represent a potential novel therapy to prevent bone erosions.

Depression symptoms following immune response to a challenge have been reported after the recovery from sickness. A RNA-Seq study of the dysregulation of the microglia transcriptome in a model of inflammation-associated depressive behavior was undertaken. The transcriptome of microglia from mice at day 7 after Bacille Calmette Guérin (BCG) challenge was compared to that from unchallenged Control mice and to the transcriptome from peripheral macrophages from the same mice. Among the 562 and 3,851 genes differentially expressed between BCG-challenged and Control mice in microglia and macrophages respectively, 353 genes overlapped between these cells types. Among the most differentially expressed genes in the microglia, serum amyloid A3 (Saa3) and cell adhesion molecule 3 (Cadm3) were over-expressed and coiled-coil domain containing 162 (Ccdc162) and titin-cap (Tcap) were under-expressed in BCG-challenged relative to Control. Many of the differentially expressed genes between BCG-challenged and Control mice were associated with neurological disorders encompassing depression symptoms. Across cell types, S100 calcium binding protein A9 (S100A9), interleukin 1 beta (Il1b) and kynurenine 3-monooxygenase (Kmo) were differentially expressed between challenged and control mice. Immune response, chemotaxis, and chemokine activity were among the functional categories enriched by the differentially expressed genes. Functional categories enriched among the 9,117 genes differentially expressed between cell types included leukocyte regulation and activation, chemokine and cytokine activities, MAP kinase activity, and apoptosis. More than 200 genes exhibited alternative splicing events between cell types including WNK lysine deficient protein kinase 1 (Wnk1) and microtubule-actin crosslinking factor 1(Macf1). Network visualization revealed the capability of microglia to exhibit transcriptome dysregulation in response to immune challenge still after resolution of sickness symptoms, albeit lower than that observed in macrophages. The persistent transcriptome dysregulation in the microglia shared patterns with neurological disorders indicating that the associated persistent depressive symptoms share a common transcriptome basis.