Identification and assignment of the human NIMA-related protein kinase 7 gene (NEK7) to human chromosome 1q31.3

Revisiting the inhibitory potential of protein kinase inhibitors against NEK7 protein via comprehensive computational investigations

The NEK7 protein is required for spindle formation, cell division, and the activation of the NLRP3 inflammasome receptor. The aberrant expression of NEK7 has been implicated to the growth of metastasis and severe inflammatory conditions like rheumatoid arthritis, liver cirrhosis, and gout. An emergent target for the development of anti-cancer drugs is NEK7. In this context, the PubChem database was used to retrieve the 675 compound library and FDA-approved protein kinase inhibitors, which were then thoroughly examined via in-silico experiments. Computational studies investigated the binding orientation, electronic, and thermodynamic characteristics of drug candidates related to target protein. Drugs were investigated using density functional theory and molecular docking to find binding interactions with NEK7. Molecular dynamic simulations assessed interactions and stability of protein-ligand complex. DFT analyses showed that selected compounds maintained a significant amount of chemical reactivity in both liquid and gaseous states. Alectinib, Crizotinib, and compound 146476703 all displayed promising molecular interactions, according to molecular docking studies, with docking scores of - 32.76, - 30.54, and - 34.34 kJ/mol, respectively. Additionally, MD simulations determined the stability and dynamic characteristics of the complex over a 200 ns production run. The current study's findings indicate that the drugs Alectinib, Crizotinib, and compound 146476703 can successfully inhibit the overexpression of the NEK7 protein. To discover more potent drugs against NEK7, it is recommended to synthesize the derivatives of Alectinib and Crizotinib and carry out additional in-vitro and in-vivo studies at the molecular level.

In Mitosis You Are Not: The NIMA Family of Kinases in Aspergillus, Yeast, and Mammals

The Never in mitosis gene A (NIMA) family of serine/threonine kinases is a diverse group of protein kinases implicated in a wide variety of cellular processes, including cilia regulation, microtubule dynamics, mitotic processes, cell growth, and DNA damage response. The founding member of this family was initially identified in Aspergillus and was found to play important roles in mitosis and cell division. The yeast family has one member each, Fin1p in fission yeast and Kin3p in budding yeast, also with functions in mitotic processes, but, overall, these are poorly studied kinases. The mammalian family, the main focus of this review, consists of 11 members named Nek1 to Nek11. With the exception of a few members, the functions of the mammalian Neks are poorly understood but appear to be quite diverse. Like the prototypical NIMA, many members appear to play important roles in mitosis and meiosis, but their functions in the cell go well beyond these well-established activities. In this review, we explore the roles of fungal and mammalian NIMA kinases and highlight the most recent findings in the field.

Inhibition of NEK7 Suppressed Hepatocellular Carcinoma Progression by Mediating Cancer Cell Pyroptosis

NIMA-related kinase 7 (NEK7) is a serine/threonine kinase involved in cell cycle progression via mitotic spindle formation and cytokinesis. It has been related to multiple cancers, including breast cancer, hepatocellular cancer, lung cancer, and colorectal cancer. Moreover, NEK7 regulated the NLRP3 inflammasome to activate Caspase-1, resulting in cell pyroptosis. In the present study, we investigated whether NEK7 is involved in cell pyroptosis of hepatocellular carcinoma (HCC). Interestingly, we found that NEK7 was significantly related to expression of pyroptosis marker GSDMD in HCC. We found that NEK7 expression was significantly correlated with GSDMD expression in bioinformatics analysis, and NEK7 expression was significantly co-expressed with GSDMD in our HCC specimens. Cell viability, migration, and invasion capacity of HCC cell lines were inhibited, and the tumor growth in the xenograft mouse model was also suppressed following knockdown of NEK7 expression. Mechanistic studies revealed that knockdown of NEK7 in HCC cells significantly upregulated the expression of pyroptosis markers such as NLRP3, Caspase-1, and GSDMD. Coculture of HCC cells stimulated hepatic stellate cell activation by increasing p-ERK1/2 and α-SMA. Knockdown of NEK7 impaired the stimulation of HCC cells. Therefore, downregulation of NEK7 inhibited cancer–stromal interaction by triggering cancer cell pyroptosis. Taken together, this study highlights the functional role of NEK7-regulated pyroptosis in tumor progression and cancer–stromal interaction of HCC, suggesting NEK7 as a potential target for a new therapeutic strategy of HCC treatment.

Targeting the NLRP3 inflammasome in cardiovascular diseases

The NACHT, leucine-rich repeat (LRR), and pyrin domain (PYD)-containing protein 3 (NLRP3) inflammasome is an intracellular sensing protein complex that plays a major role in innate immunity. Following tissue injury, activation of the NLRP3 inflammasome results in cytokine production, primarily interleukin(IL)-1β and IL-18, and, eventually, inflammatory cell death - pyroptosis. While a balanced inflammatory response favors damage resolution and tissue healing, excessive NLRP3 activation causes detrimental effects. A key involvement of the NLRP3 inflammasome has been reported across a wide range of cardiovascular diseases (CVDs). Several pharmacological agents selectively targeting the NLRP3 inflammasome system have been developed and tested in animals and early phase human studies with overall promising results. While the NLRP3 inhibitors are in clinical development, multiple randomized trials have demonstrated the safety and efficacy of IL-1 blockade in atherothrombosis, heart failure and recurrent pericarditis. Furthermore, the non-selective NLRP3 inhibitor colchicine has been recently shown to significantly reduce cardiovascular events in patients with chronic coronary disease. In this review, we will outline the mechanisms driving NLRP3 assembly and activation, and discuss the pathogenetic role of the NLRP3 inflammasome in CVDs, providing an overview of the current and future therapeutic approaches targeting the NLRP3 inflammasome.

NEK7 Promotes Pancreatic Cancer Progression And Its Expression Is Correlated With Poor Prognosis

The prognosis for pancreatic ductal adenocarcinoma (PDAC) patients is still dismal. Elucidation of associated genomic alteration may provide effective therapeutic strategies for PDAC treatment. NIMA-related protein kinase 7 is widely expressed in various tumors, including breast cancer, colorectal cancer and lung cancer, and promotes the proliferation of liver cancer cells in vitro and in vivo. We investigated the protein expression level of NEK7 in tumor tissues and adjacent normal tissues using immunohistochemistry of 90 patients with PADC. Meanwhile, the RNA expression level of NEK7 was examined using database-based bioinformatic analysis. Correlation and significance of NEK7 expression with patient clinicopathological features and prognosis were examined. Cell proliferation, cell adhesion, migration and invasion capabilities were measured following downregulation of NEK7 expression. 3D tumor organoids of pancreatic cancer were established and splenic xenografted into nude mice, then liver metastatic ability of NEK7 was evaluated in following 4 weeks. We observed NEK7 expression was upregulated in tumor tissues compared to normal tissues at both RNA and protein levels using bioinformatic analysis and immunohistochemistry analysis in PDAC. NEK7 expression was undetectable in normal pancreatic ducts; NEK7 was overexpressed in primary tumor of PDAC; NEK7 expression was highly correlated with advanced T stage, poorly differentiated histological grade invasive ductal carcinoma, and lymphatic invasion. Meanwhile, patients with higher NEK7 expression accompanied by worse survival outcome. Moreover, NEK7 promoted migration, invasion, adhesion, proliferation and liver metastatic ability of pancreatic cancer cells. Taken together, our data indicate that NEK7 promotes pancreatic cancer progression and it may be a potential marker for PDAC prognosis.

Physiological and Pathological Roles of Mammalian NEK7

NEK7 is the smallest NIMA-related kinase (NEK) in mammals. The pathological and physiological roles of NEK7 have been widely reported in many studies. To date, the major function of NEK7 has been well documented in mitosis and NLRP3 inflammasome activation, but the detailed mechanisms of its regulation remain unclear. This review summarizes current advances in NEK7 research involving mitotic regulation, NLRP3 inflammasome activation, related diseases and potential inhibitors, which may provide new insights into the understanding and therapy of the diseases associated with NEK7, as well as the subsequent studies in the future.

NEK7 Coordinates Rapid Neuroinflammation After Subarachnoid Hemorrhage in Mice

Background: Subarachnoid hemorrhage (SAH) is a devastating disease which leads to high morbidity and mortality. Recent studies have indicated that, never in mitosis gene A-related expressed kinase 7 (NEK7), is involved in NLRP3 (NLR family, pyrin domain containing 3) associated inflammation, which may result in subsequent cellular and vascular damage. The aim of this study was to investigate whether NEK7 is involved in the pathophysiology of subarachnoid hemorrhage.

Methods: 455 adult male C57B6J mice, weighing 22 to 30 g, were used to investigate the time course of NEK7 expression in the ipsilateral cortex after SAH, and to investigate the intrinsic function and mechanism of NEK7. A vascular puncture model was used to create the mouse SAH model, and intracerebroventricular injection was used to deliver NEK7 recombinant protein, NEK7 small interfering RNA, nigericin, and MCC950. Neurological score, brain water content, Evans blue extravasation, immunofluorescence, and western blot were evaluated for neurological outcome, neuronal apoptosis, blood-brain barrier damage, microglia accumulation, and the mechanism of NEK7 and NLRP3 activation.

Results: Our results exhibited that intrinsic NEK7 was elevated after SAH in the cortex of the left/ipsilateral hemisphere and was colocalized with microglia, endothelial cells, neuron, astrocyte, and oligodendrocyte, and highly expressed in microglia and endothelial cells after SAH. NEK7 recombinant protein aggravated neurological deficits, brain edema, neuronal apoptosis, BBB permeability, microglial accumulation, and activated caspase-1 and IL-1β maturation, while NEK7 small interfering RNA injection reversed those effects. Nigericin administration enhanced ASC oligomerization, caspase-1 and IL-1β maturation without increasing the protein level of NLRP3, and ASC oligomerization and caspase-1 IL-1β maturation reduced when combined with NEK7 knockdown or MCC950 delivery. We found the level of NEK7 expression increased after SAH and could activate the downstream NLRP3 pathway to induce caspase-1, IL-1β expression and then increased the BBB opening, microglia accumulation and neuronal apoptosis after SAH.

Conclusions: This study demonstrated for the first time that NEK7 mediated the harmful effects of neuronal apoptosis and BBB disruption after SAH, which may potentially be mediated by the NEK7/NLRP3 signal. NEK7 served as a co-component for NLRP3 inflammasome activation after SAH. NEK7 may be a promising target on the management of SAH patients.

The cell adhesion gene PVRL3 is associated with congenital ocular defects

We describe a male patient (patient DGAP113) with a balanced translocation, 46,XY,t(1;3)(q31.3;q13.13), severe bilateral congenital cataracts, CNS abnormalities and mild developmental delay. Fluorescence in situ hybridization (FISH) and suppression PCR demonstrated that the chromosome 3 breakpoint lies ~515 kb upstream of the PVRL3 gene, while the chromosome 1 breakpoint lies ~50 kb upstream of the NEK7 gene. Despite the fact that NEK7 is closer to a translocation breakpoint than PVRL3, NEK7 transcript levels are unaltered in patient DGAP113 lymphoblastoid cells and Nek7-deficient mice exhibit no detectable ocular phenotype. In contrast, the expression of PVRL3, which encodes the cell adhesion protein Nectin 3, is significantly reduced in patient DGAP113 lymphoblastoid cells, likely due to a position effect caused by the chromosomal translocation. Nectin 3 is expressed in the mouse embryonic ciliary body and lens. Moreover, Pvrl3 knockout mice as well as a spontaneous mouse mutant ari (anterior retinal inversion), that maps to the Pvrl3 locus, exhibit lens and other ocular defects involving the ciliary body. Collectively, these data identify PVRL3 as a critical gene involved in a Nectin-mediated cell-cell adhesion mechanism in human ocular development.

Gonadal transcriptome alterations in response to dietary energy intake: sensing the reproductive environment

Reproductive capacity and nutritional input are tightly linked and animals' specific responses to alterations in their physical environment and food availability are crucial to ensuring sustainability of that species. We have assessed how alterations in dietary energy intake (both reductions and excess), as well as in food availability, via intermittent fasting (IF), affect the gonadal transcriptome of both male and female rats. Starting at four months of age, male and female rats were subjected to a 20% or 40% caloric restriction (CR) dietary regime, every other day feeding (IF) or a high fat-high glucose (HFG) diet for six months. The transcriptional activity of the gonadal response to these variations in dietary energy intake was assessed at the individual gene level as well as at the parametric functional level. At the individual gene level, the females showed a higher degree of coherency in gonadal gene alterations to CR than the males. The gonadal transcriptional and hormonal response to IF was also significantly different between the male and female rats. The number of genes significantly regulated by IF in male animals was almost 5 times greater than in the females. These IF males also showed the highest testosterone to estrogen ratio in their plasma. Our data show that at the level of gonadal gene responses, the male rats on the IF regime adapt to their environment in a manner that is expected to increase the probability of eventual fertilization of females that the males predict are likely to be sub-fertile due to their perception of a food deficient environment.

Human Misato regulates mitochondrial distribution and morphology

Misato of Drosophila melanogaster and Saccharomyces cerevisiae DML1 are conserved proteins having a homologous region with a part of the GTPase family that includes eukaryotic tubulin and prokaryotic FtsZ. We characterized human Misato sharing homology with Misato of D. melanogaster and S. cerevisiae DML1. Tissue distribution of Misato exhibited ubiquitous distribution. Subcellular localization of the protein studied using anti-Misato antibody suggested that it is localized to the mitochondria. Further experiments of fractionating mitochondria revealed that Misato was localized to the outer membrane. The transfection of Misato siRNA led to growth deficiencies compared with control siRNA transfected HeLa cells, and the Misato-depleted HeLa cells showed apoptotic nuclear fragmentation resulting in cell death. After silencing of Misato, the filamentous mitochondrial network disappeared and fragmented mitochondria were observed, indicating human Misato has a role in mitochondrial fusion. To examine the effects of overexpression, COS-7 cells were transfected with cDNA encoding EGFP-Misato. Its overexpression resulted in the formation of perinuclear aggregations of mitochondria in these cells. The Misato-overexpressing cells showed low viability and had no nuclei or a small and structurally unusual ones. These results indicated that human Misato has a role(s) in mitochondrial distribution and morphology and that its unregulated expression leads to cell death.

Nek8, a NIMA family kinase member, is overexpressed in primary human breast tumors

The family of human Nek (NIMA Related Kinase) kinases currently contains 11 members. We have identified Nek8 as a new member of the Nek kinase family. For many of the Nek family members, primary tumor expression data and function have been limited. However, all of the Nek family proteins share considerable homology with the Never In Mitosis, gene A (NIMA) kinase from the filamentous fungus Aspergillus nidulans. NIMA, as well as its most closely related human ortholog, Nek2, are required for G(2)/M progression and promote centrosome maturation during mitosis. We isolated Nek8 from a primary human colon cDNA library, and found it to be highly homologous to murine Nek8. Recently, a previously named Nek8 sequence was renamed Nek9/Nercc1 in Genbank due to its lack of homology to murine Nek8 and its high homology to murine Nek9. Interestingly, in our study, phylogenetic analysis suggests that human Nek8 and Nek9 form a subfamily within the Nek family. Nek8 has high homology to the Nek family kinase domain as well as to a regulator of chromosome condensation domain (RCC1), which is also present in Nek9. The open reading frame of human Nek8 encodes a 692 amino-acid protein with a calculated molecular weight of 75 kDa. Nek8 is differently expressed between normal human breast tissue and breast tumors. Overexpression of a mutated kinase domain Nek8 in U2-0S cells led to a decrease in actin protein, and a small increase in the level of cdk1/cyclinB1. Our data demonstrate for the first time that Nek8 is a novel tumor associated gene, and shares considerable sequence homology with the Nek family of protein kinases and may be involved in G(2)/M progression.

Nek11, a new member of the NIMA family of kinases, involved in DNA replication and genotoxic stress responses

DNA replication and genotoxic stresses activate various checkpoint-associated protein kinases, and checkpoint dysfunction often leads to cell lethality. Here, we have identified new members of the mammalian NIMA family of kinases, termed Nek11L and Nek11S (NIMA-related kinase 11 Long and Short isoform) as novel DNA replication/damage stresses-responsive kinases. Molecular cloning and biochemical studies showed that the catalytic domain of Nek11 is most similar to Nek4 and Nek3, and substrate specificity of Nek11L is distinguishable from those of NIMA and Nek2. The expression of nek11L mRNA increased through S to G(2)/M phase, and subcellular localization of Nek11 protein altered between interphase and prometaphase, suggesting multiple roles of Nek11. We found an activation of Nek11 kinase activity when cells were treated with various DNA-damaging agents and replication inhibitors, and this activation of Nek11 was suppressed by caffeine in HeLaS3 cells. The transient expression of wild-type Nek11L enhanced the aphidicolin-induced S-phase arrest, whereas the aphidicolin-induced S-phase arrest was reduced in the U2OS cell lines expressing kinase-negative Nek11L (K61R), and these cells were more sensitive to aphidicolin-induced cell lethality. Collectively, these results suggest that Nek11 has a role in the S-phase checkpoint downstream of the caffeine-sensitive pathway.

Molecular cloning and characterization of the human NIMA-related protein kinase 3 gene (NEK3)

NEKs (NIMA-related kinases) are a group of protein kinases sharing high amino acid sequence identities with NIMA (never in mitosis gene a) which control mitosis in Aspergillus nidulans. We have cloned a cDNA for human NEK3, a novel human gene structurally related to NIMA, by RT-PCR. Its open reading frame encodes a protein of 489 amino acid residues with the calculated molecular mass of 56.0 kDa and a predicted pI of 6.58. Phylogenetic analysis suggests that mouse and human NEK3s constitute a subfamily within the NIMA family of protein kinases. The expression pattern of NEK3 was studied by RT-PCR and a high level of expression was detected in testis, ovary, and brain, with low-level expression being detected in most of the tissues studied. NEK3 mRNA was detected in all the proliferating cell lines studied, and the amount did not change during the cell cycle. The human NEK3 gene was assigned to human chromosome 13 by somatic cell hybrids and 13q14.2 by radiation hybrid mapping.