Krüppel-like transcription factor 8 (Klf8) is expressed and active in the neurons of the mouse brain

Genome-Wide Identification, Evolution, and miRNA-22 Regulation of Kruppel-Like Factor (KLF) Gene Family in Chicken (Gallus gallus)

Krüppel-like factors (KLFs) are a class of fundamental transcription factors that are widely present in various eukaryotes from nematodes to humans, named after their DNA binding domain which is highly homologous to the Krüppel factor in fruit flies. To investigate the composition, organization, and evolutionary trajectory of KLF gene family members in chickens, in our study, we leveraged conserved sequences of KLF genes from representative classes across fish, amphibians, birds, and mammals as foundational sequences. Bioinformatic tools were employed to perform homology alignment on the chicken genome database, ultimately identifying the KLF family members present in chickens. The gene structure, phylogenetic analysis, conserved base sequences, physicochemical properties, collinearity analysis, and protein structure were then analyzed using bioinformatic tools. Additionally, the impact of miRNA-22, related to poultry lipid metabolism, on the expression of the KLF gene family in the liver, heart, and muscle of Qingyuan partridge chickens was explored. The results showed that: (1) compared to fish, the KLF family in birds is more closely related to mammals and amphibians; (2) KLFs within the same subgroups are likely to be derived from a common ancestral gene duplication; (3) KLF3/8/12 in the same subgroup may have some similar or overlapping functions; (4) the motif 4 of KLF5 was most likely lost during evolution; (5) KLF9 may perform a similar function in chickens and pigs; (6) there are collinear relationships between certain KLF genes, indicating that there are related biomolecular functions between these KLF genes; (7) all members of the KLF family in chickens are non-transmembrane proteins; and (8) interference and overexpression of miRNA-22 in Qingyuan partridge chickens can affect the expression levels of KLF genes in liver, heart, and muscle.

The kruppel-like factor (KLF) family, diseases, and physiological events

The Kruppel-Like Factor family of regulatory proteins, which has 18 members, is transcription factors. This family contains zinc finger proteins, regulates the activation and suppression of transcription, and binds to DNA, RNA, and proteins. Klfs related to the immune system are Klf1, Klf2, Klf3, Klf4, Klf6, and Klf14. Klfs related to adipose tissue development and/or glucose metabolism are Klf3, Klf7, Klf9, Klf10, Klf11, Klf14, Klf15, and Klf16. Klfs related to cancer are Klf3, Klf4, Klf5, Klf6, Klf7, Klf8, Klf9, Klf10, Klf11, Klf12, Klf13, Klf14, Klf16, and Klf17. Klfs related to the cardiovascular system are Klf4, Klf5, Klf10, Klf13, Klf14, and Klf15. Klfs related to the nervous system are Klf4, Klf7, Klf8, and Klf9. Klfs are associated with diseases such as carcinogenesis, oxidative stress, diabetes, liver fibrosis, thalassemia, and the metabolic syndrome. The aim of this review is to provide information about the relationship of Klfs with some diseases and physiological events and to guide future studies.

Genetic deletion of Krüppel-like factor 11 aggravates traumatic brain injury

BACKGROUND

The long-term functional recovery of traumatic brain injury (TBI) is hampered by pathological events, such as parenchymal neuroinflammation, neuronal death, and white matter injury. Krüppel-like transcription factor 11 (KLF 11) belongs to the zinc finger family of transcription factors and actively participates in various pathophysiological processes in neurological disorders. Up to now, the role and molecular mechanisms of KLF11 in regulating the pathogenesis of brain trauma is poorly understood.

METHODS

KLF11 knockout (KO) and wild-type (WT) mice were subjected to experimental TBI, and sensorimotor and cognitive functions were evaluated by rotarod, adhesive tape removal, foot fault, water maze, and passive avoidance tests. Brain tissue loss/neuronal death was examined by MAP2 and NeuN immunostaining, and Cresyl violet staining. White matter injury was assessed by Luxol fast blue staining, and also MBP/SMI32 and Caspr/Nav1.6 immunostaining. Activation of cerebral glial cells and infiltration of blood-borne immune cells were detected by GFAP, Iba-1/CD16/32, Iba-1/CD206, Ly-6B, and F4/80 immunostaining. Brian parenchymal inflammatory cytokines were measured with inflammatory array kits.

RESULTS

Genetic deletion of KLF11 worsened brain trauma-induced sensorimotor and cognitive deficits, brain tissue loss and neuronal death, and white matter injury in mice. KLF11 genetic deficiency in mice also accelerated post-trauma astrocytic activation, promoted microglial polarization to a pro-inflammatory phenotype, and increased the infiltration of peripheral neutrophils and macrophages into the brain parenchyma. Mechanistically, loss-of-KLF11 function was found to directly increase the expression of pro-inflammatory cytokines in the brains of TBI mice.

CONCLUSION

KLF11 acts as a novel protective factor in TBI. KLF11 genetic deficiency in mice aggravated the neuroinflammatory responses, grey and white matter injury, and impaired long-term sensorimotor and cognitive recovery. Elucidating the functional importance of KLF11 in TBI may lead us to discover novel pharmacological targets for the development of effective therapies against brain trauma.

Serum aberrant expression of miR-24-3p and its diagnostic value in Alzheimer's disease

Aim: This study aimed to evaluate the effect of miR-24-3p in Alzheimer's disease (AD). Materials & methods: A total of 198 participants were recruited in this study, including 104 AD patients and 94 healthy controls. Expression of miR-24-3p was detected using quantitative real-time PCR. Receiver-operating characteristic curve was used to assess the diagnostic value of miR-24-3p. In vitro AD model was established to evaluate the effect of miR-24-3p. The downstream target was detected by luciferase reporter gene assay. Results: Expression of miR-24-3p showed 1.6-fold increase in AD group compared with healthy controls, and a negative correlation of miR-24-3p with mini-mental state examination score was obtained. Receiver-operating characteristic curve showed satisfactory diagnostic accuracy. Downregulation of miR-24-3p promoted cell proliferation and inhibited cell apoptosis. KLF8 is a target gene of miR-24-3p. Conclusion: MiR-24-3p has a certain value in the diagnosis of AD and may be a potential biomarker.

Proteomic Profile of Mouse Brain Aging Contributions to Mitochondrial Dysfunction, DNA Oxidative Damage, Loss of Neurotrophic Factor, and Synaptic and Ribosomal Proteins

The deleterious effects of aging on the brain remain to be fully elucidated. In the present study, proteomic changes of young (4-month) and aged (16-month) B6129SF2/J male mouse hippocampus and cerebral cortex were investigated by using nano liquid chromatography tandem mass spectrometry (NanoLC-ESI-MS/MS) combined with tandem mass tag (TMT) labeling technology. Compared with the young animals, 390 hippocampal proteins (121 increased and 269 decreased) and 258 cortical proteins (149 increased and 109 decreased) changed significantly in the aged mouse. Bioinformatic analysis indicated that these proteins are mainly involved in mitochondrial functions (FIS1, DRP1), oxidative stress (PRDX6, GSTP1, and GSTM1), synapses (SYT12, GLUR2), ribosome (RPL4, RPS3), cytoskeletal integrity, transcriptional regulation, and GTPase function. The mitochondrial fission-related proteins FIS1 and DRP1 were significantly increased in the hippocampus and cerebral cortex of the aged mice. Further results in the hippocampus showed that ATP content was significantly reduced in aged mice. A neurotrophin brain-derived neurotrophic factor (BNDF), a protein closely related with synaptic plasticity and memory, was also significantly decreased in the hippocampus of the aged mice, with the tendency of synaptic protein markers including complexin-2, synaptophysin, GLUR2, PSD95, NMDAR2A, and NMDAR1. More interestingly, 8-hydroxydeoxyguanosine (8-OHdG), a marker of DNA oxidative damage, increased as shown by immunofluorescence staining. In summary, we demonstrated that aging is associated with systemic changes involving mitochondrial dysfunction, energy reduction, oxidative stress, loss of neurotrophic factor, synaptic proteins, and ribosomal proteins, as well as molecular deficits involved in various physiological/pathological processes.

Movement deficits and neuronal loss in basal ganglia in TRPC1 deficient mice

Transient receptor potential cation (TRPC) channel proteins are abundantly expressed in brain. However, the functions of these TRPC proteins such as TRPC1 are largely unclear. In this study, we reported that TRPC1 deficiency caused movement disorder as measured by swimming test, modified open field test and sunflower seeds eating test. Immunofluorescent staining showed significant loss of both NeuN-positive cells and tyrosine hydroxylase (TH) -positive cells in the caudate putamen (CPu), the external globus pallidus (GPe), and the substantia nigra pars reticulata (SNr) in 5-month-old TRPC1 knockout mice (TRPC1-/-) compared to the wild type (WT) mice. TUNEL staining further revealed that TUNEL-positive cells were significantly increased in the CPu, GPe, and SNr of TRPC1-/- mice. Taken together, these data suggests that TRPC1 is involved in the control of motor function by inhibiting the apoptosis of neuronal cells of basal ganglia.

Molecular identification and functional analysis of KLF2 in Plecoglossus altivelis (ayu): It's regulatory role in monocyte/macrophage activation

Monocytes/macrophages (MO/MФ) play an important role in the response to infection in Plecoglossus altivelis (ayu). However, the role of transcription factors in the function of ayu MO/MФ is poorly understood. Here, we cloned the cDNA sequence of the Kruppel-like factor 2 (PaKLF2) gene from ayu. Phylogenetic analysis indicated that PaKLF2 was closest to that of Atlantic salmon (Salmo salar). Real time quantitative PCR (RT-qPCR) revealed that the PaKLF2 mRNA level was highest in the peripheral blood mononuclear cells among all tested tissues. The mRNA expression of PaKLF2 was upregulated in the head kidney, liver, spleen, and brain after Listonella anguillarum infection. Subsequently, PaKLF2 was expressed and purified to prepare anti-PaKLF2 antibodies. After L. anguillarum challenge, the PaKLF2 mRNA and protein levels were significantly upregulated in ayu MO/MФ. Moreover, PaKLF2 knockdown in MO/MФ resulted in the enhancement of cytokine production as well as phagocytotic and bactericidal capability. Therefore, PaKLF2 may modulate the immune response in ayu by suppressing the function of MO/MФ.

Histone deacetylase-mediated regulation of chondroitin 4-O-sulfotransferase-1 (Chst11) gene expression by Wnt/β-catenin signaling

Chondroitin sulfate (CS) proteoglycans are abundant extracellular and cell surface molecules that consist of a protein core to which highly sulfated CS chains are covalently attached. The CS backbone is composed of repeating disaccharide units [-GlcA-GalNAc-]_n, and during synthesis the CS chains acquire structural variability due to the action of sulfotransferases. Specific sulfation patterns are recognized by a large variety of proteins, including growth factors, morphogens, and extracellular matrix proteins, and these interactions regulate key events in development and normal physiology. Therefore, it is important to understand how gene expression of CS sulfotransferases is regulated. We previously found that Wnt signaling regulates the sulfation patterns of cell-associated CS chains by suppressing expression of chondroitin 4-O-sulfotaransferase-1 (C4ST-1), a CS biosynthetic enzyme. Here we investigated the mechanism underlying the regulation of C4ST-1 gene expression by Wnt/β-catenin signaling. Although C4ST-1 mRNA of 3'-UTR contains three binding sites for microRNAs (miRNA), these miRNAs played little role in controlling C4ST-1 gene expression. In contrast, the suppression of C4ST-1 gene expression by Wnt/β-catenin signaling can be recovered by treatment with trichostatin A, but not with 5'-aza-2'-deoxycytidine. These results suggest that the Wnt/β-catenin signal pathway controls C4ST-1 gene expression mainly through histone deacetylase.