Effects of the FHL2 gene on the development of subcutaneous and intramuscular adipocytes in goats.

BACKGROUND: Adipose tissue affects not only the meat quality of domestic animals, but also human health. Adipocyte differentiation is regulated by a series of regulatory genes and cyclins. Four and half-LIM protein (FHL2) is positively correlated with the hypertrophy of adipocytes and can cause symptoms such as obesity and diabetes. RESULT: In the transcriptome sequencing analysis of intramuscular adipocytes after three days of differentiation, the differentially expressed gene FHL2 was found. To further explore the biological significance of the differentially expressed gene FHL2, which was downregulated in the mature adipocytes. We revealed the function of FHL2 in adipogenesis through the acquisition and loss of function of FHL2. The results showed that the overexpression of FHL2 significantly increased the expression of adipogenic genes (PPARγ, C/EBPß) and the differentiation of intramuscular and subcutaneous adipocytes. However, silencing FHL2 significantly inhibited adipocyte differentiation. The overexpression of FHL2 increased the number of adipocytes stained with crystal violet and increased the mRNA expression of proliferation marker genes such as CCNE, PCNA, CCND and CDK2. In addition, it significantly increased the rate of EdU positive cells. In terms of apoptosis, overexpression of FHL2 significantly inhibited the expression of P53 and BAX in both intramuscular and subcutaneous adipocytes, which are involved in cell apoptosis. However, overexpression of FHL2 promoted the expression of BCL, but was rescued by the silencing of FHL2. CONCLUSIONS: In summary, FHL2 may be a positive regulator of intramuscular and subcutaneous adipocyte differentiation and proliferation, and acts as a negative regulator of intramuscular and subcutaneous adipocyte apoptosis. These findings provide a theoretical basis for the subsequent elucidation of FHL2 in adipocytes.

Genetic polymorphisms of LMX1B and MLXIP are associated with hip osteoarthritis in the Chinese population.

Aims: A large genome-wide analyses of UK Biobank data reported 15 novel loci associated with the susceptibility of hip osteoarthritis (HOA). We aimed to replicate the association of these loci with HOA in the Chinese population.Methods: A total of 13 Single Nucleotide Polymorphisms were genotyped in 892 HOA patients and 1123 healthy controls.Results: The risk allele frequency of rs62578127 and rs11059094 was significantly higher in the patients than in the controls. The mRNA expression of LMX1B (p = 0.01) and MLXIP (p = 0.001) were significantly increased in HOA tissues.Conclusion: We successfully replicated two novel susceptible loci of HOA and further characterized two potential causative genes.

[Box: see text].

Planarian LDB and SSDP proteins scaffold transcriptional complexes for regeneration and patterning.

Sequence-specific transcription factors often function as components of large regulatory complexes. LIM-domain binding protein (LDB) and single-stranded DNA-binding protein (SSDP) function as core scaffolds of transcriptional complexes in animals and plants. Little is known about potential partners and functions for LDB/SSDP complexes in the context of tissue regeneration. In this work, we find that planarian LDB1 and SSDP2 promote tissue regeneration, with a particular function in anterior regeneration and mediolateral polarity reestablishment. We find that LDB1 and SSDP2 interact with one another and with characterized planarian LIM-HD proteins Arrowhead, Islet1, and Lhx1/5-1. We also show that SSDP2 and LDB1 function with islet1 in polarity reestablishment and with lhx1/5-1 in serotonergic neuron maturation. Finally, we find new roles for LDB1 and SSDP2 in regulating gene expression in the planarian intestine and parenchyma; these functions are likely LIM-HD-independent. Together, our work provides insight into LDB/SSDP complexes in a highly regenerative organism. Further, our work provides a strong starting point for identifying and characterizing potential binding partners of LDB1 and SSDP2 and for exploring roles for these proteins in diverse aspects of planarian physiology.

Interference with sphingosine kinase-1 reduces the hydrogen peroxide-induced oxidative stress damage in melanocytes through four and a half LIM domains 2.

Vitiligo is featured by manifestation of white maculae and primarily results from oxidative stress. Sphingosine kinase-1 (SPHK1) participates in oxidative stress. This paper was devised to explore the role of SPHK1 in vitiligo and to disclose the mechanism. PIG1 cell viability was appraised utilizing cell counting kit-8 assay while Western blot detected SPHK1 and four and a half LIM domains 2 (FHL2). The transduction efficacy of small interfering RNA (siRNA)-SPHK1, siRNA-FHL2 and pcDNA3.1 plasmid overexpressing FHL2 (Ov-FHL2) was checked using Western blot. Flow cytometry detected cell apoptotisis. Western blot detected mitochondrial cytochrome c (Mit-Cyt-c) and cytosolic cytochrome c (Cyto-Cyt-c). Dichloro-dihydro-fluorescein diacetate (DCFH-DA) detected reactive oxygen species (ROS) activity while oxidative stress markers were evaluated using corresponding assay kits. SPHK1 expression was discovered to be increased in hydrogen peroxide (H2O2)-challenged PIG1 cells and SPHK1 interference alleviated H2O2-challenged viability damage, apoptosis, oxidative stress and FHL2 expression in PIG1 cells. FHL2 depletion could suppress viability damage, apoptosis and oxidative stress in H2O2-challenged PIG1 cells. Rescue experiments demonstrated that the suppressive impacts of SPHK1 deficiency on PIG1 cell viability, apoptosis and oxidative stress induced by H2O2 were offset by FHL2 overexpression. Collectively, SPHK1 knockdown protected against vitiligo via the regulation of FHL2.

ISL1-overexpressing BMSCs attenuate renal ischemia-reperfusion injury by suppressing apoptosis and oxidative stress through the paracrine action.

Ischemia-reperfusion injury (IRI) is a major event in renal transplantation, leading to adverse outcomes. Bone marrow mesenchymal stem cells (BMSCs) are novel promising therapeutics for repairing kidney injuries. The therapeutic efficacy of BMSCs with ISL1 overexpression in renal IRI and its underlying mechanism need to be investigated. The unilateral renal IRI rat model was established to mimic clinical acute kidney injury. Rats were injected with PBS, BMSCs-Scrambled or BMSCs-ISL1 via the tail vein at the timepoint of reperfusion, and then sacrificed after 24 h of reperfusion. The administration of BMSCs-ISL1 significantly improved renal function, inhibited tubular cells apoptosis, inflammation, oxidative stress in rats. In vitro, HKC cells subjected to H2O2 stimulation were pretreated with the conditioned medium (CM) of BMSCs-Scrambled or BMSCs-ISL1. The pretreatment of ISL1-CM attenuated apoptosis and oxidative stress induced by H2O2 in HKC cells. Our proteomic data suggested that haptoglobin (Hp) was one of the secretory proteins in ISL1-CM. Subsequent experiments confirmed that Hp was the important paracrine factor from BMSCs-ISL1 that exerted anti-apoptotic and antioxidant functions. Mechanistically, Hp played a cytoprotective role via the inhibition of ERK signaling pathway, which could be abrogated by Ro 67-7476, the ERK phosphorylation agonist. The results suggested that paracrine action may be the main mechanism for BMSCs-ISL1 to exert protective effects. As an important anti-apoptotic and antioxidant factor in ISL1-CM, Hp may serve as a new therapeutic agent for treating IRI, providing new insights for overcoming the long-term adverse effects of stem cell therapy.

Combined Pituitary Hormone Deficiency in lhx4-Knockout Zebrafish.

LIM homeobox 4 (LHX4) is a transcription factor crucial for anterior pituitary (AP) development. Patients with LHX4 mutation suffer from combined pituitary hormone deficiency (CPHD), short statures, reproductive and metabolic disorders and lethality in some cases. Lhx4-knockout (KO) mice fail to develop a normal AP and die shortly after birth. Here, we characterize a zebrafish lhx4-KO model to further investigate the importance of LHX4 in pituitary gland development and regulation. At the embryonic and larval stages, these fish express lower levels of tshb mRNA compared with their wildtype siblings. In adult lhx4-KO fish, the expressions of pituitary hormone-encoding transcripts, including growth hormone (gh), thyroid stimulating hormone (tshb), proopiomelanocortin (pomca) and follicle stimulating hormone (fshb), are reduced, the pomca promoter-driven expression in corticotrophs is dampened and luteinizing hormone (lhb)-producing gonadotrophs are severely depleted. In contrast to Lhx4-KO mice, Lhx4-deficient fish survive to adulthood, but with a reduced body size. Importantly, lhx4-KO males reach sexual maturity and are reproductively competent, whereas the females remain infertile with undeveloped ovaries. These phenotypes, which are reminiscent of those observed in CPHD patients, along with the advantages of the zebrafish for developmental genetics research, make this lhx4-KO fish an ideal vertebrate model to study the outcomes of LHX4 mutation.

Lhx4 surpasses its paralog Lhx3 in promoting the differentiation of spinal V2a interneurons.

Paralog factors are considered to ensure the robustness of biological processes by providing redundant activity in cells where they are co-expressed. However, the specific contribution of each factor is frequently underestimated. In the developing spinal cord, multiple families of transcription factors successively contribute to differentiate an initially homogenous population of neural progenitors into a myriad of neuronal subsets with distinct molecular, morphological, and functional characteristics. The LIM-homeodomain transcription factors Lhx3, Lhx4, Isl1 and Isl2 promote the segregation and differentiation of spinal motor neurons and V2 interneurons. Based on their high sequence identity and their similar distribution, the Lhx3 and Lhx4 paralogs are considered to contribute similarly to these processes. However, the specific contribution of Lhx4 has never been studied. Here, we provide evidence that Lhx3 and Lhx4 are present in the same cell populations during spinal cord development. Similarly to Lhx3, Lhx4 can form multiproteic complexes with Isl1 or Isl2 and the nuclear LIM interactor NLI. Lhx4 can stimulate a V2-specific enhancer more efficiently than Lhx3 and surpasses Lhx3 in promoting the differentiation of V2a interneurons in chicken embryo electroporation experiments. Finally, Lhx4 inactivation in mice results in alterations of differentiation of the V2a subpopulation, but not of motor neuron production, suggesting that Lhx4 plays unique roles in V2a differentiation that are not compensated by the presence of Lhx3. Thus, Lhx4 could be the major LIM-HD factor involved in V2a interneuron differentiation during spinal cord development and should be considered for in vitro differentiation of spinal neuronal populations.

Isl Identifies the Extraembryonic Mesodermal/Allantois Progenitors and is Required for Placenta Morphogenesis and Vasculature Formation.

The placenta links feto-maternal circulation for exchanges of nutrients, gases, and metabolic wastes between the fetus and mother, being essential for pregnancy process and maintenance. The allantois and mesodermal components of amnion, chorion, and yolk sac are derived from extraembryonic mesoderm (Ex-Mes), however, the mechanisms contributing to distinct components of the placenta and regulation the interactions between allantois and epithelium during chorioallantoic fusion and labyrinth formation remains unclear. Isl1 is expressed in progenitors of the Ex-Mes and allantois the Isl1 mut mouse line is analyzed to investigate contribution of Isl1+ Ex-Mes / allantoic progenitors to cells of the allantois and placenta. This study shows that Isl1 identifies the Ex-Mes progenitors for endothelial and vascular smooth muscle cells, and most of the mesenchymal cells of the placenta and umbilical cord. Deletion of Isl1 causes defects in allantois growth, chorioallantoic fusion, and placenta vessel morphogenesis. RNA-seq and CUT&Tag analyses revealed that Isl1 promotes allantoic endothelial, inhibits mesenchymal cell differentiation, and allantoic signals regulated by Isl1 mediating the inductive interactions between the allantois and chorion critical for chorionic epithelium differentiation, villous formation, and labyrinth angiogenesis. This study above reveals that Isl1 plays roles in regulating multiple genetic and epigenetic pathways of vascular morphogenesis, provides the insight into the mechanisms for placental formation, highlighting the necessity of Isl1 for placenta formation/pregnant maintenance.

A Nonsynonymous Substitution of Lhx3 Leads to Changes in Body Size in Dogs and Mice.

Lhx3 is a LIM-homeodomain transcription factor that affects body size in mammals by regulating the secretion of pituitary hormones. Akita, Shiba Inu, and Mame Shiba Inu dogs are Japanese native dog breeds that have different body sizes. To determine whether Lhx3 plays a role in the differing body sizes of these three dog breeds, we sequenced the Lhx3 gene in the three breeds, which led to the identification of an SNP in codon 280 (S280N) associated with body size. The allele frequency at this SNP differed significantly between the large Akita and the two kinds of smaller Shiba dogs. To validate the function of this SNP on body size, we introduced this change into the Lhx3 gene of mice. Homozygous mutant mice (S279N+/+) were found to have significantly increased body lengths and weights compared to heterozygous mutant (S279N+/-) and wild-type (S279N-/-) mice several weeks after weaning. These results demonstrate that a nonsynonymous substitution in Lhx3 plays an important role in regulating body size in mammals.

Missense mutation of ISL1 (E283D) is associated with the development of type 2 diabetes.

AIMS/HYPOTHESIS: Mutations in Isl1, encoding the insulin enhancer-binding protein islet-1 (ISL1), may contribute to attenuated insulin secretion in type 2 diabetes mellitus. We made an Isl1E283D mouse model to investigate the disease-causing mechanism of diabetes mellitus. METHODS: The ISL1E283D mutation (c. 849A>T) was identified by whole exome sequencing on an early-onset type 2 diabetes family and then the Isl1E283D knockin (KI) mouse model was created and an IPGTT and IPITT were conducted. Glucose-stimulated insulin secretion (GSIS), expression of Ins2 and other ISL1 target genes and interacting proteins were evaluated in isolated pancreas islets. Transcriptional activity of Isl1E283D was evaluated by cell-based luciferase reporter assay and electrophoretic mobility shift assay, and the expression levels of Ins2 driven by Isl1 wild-type (Isl1WT) and Isl1E283D mutation in rat INS-1 cells were determined by RT-PCR and western blotting. RESULTS: Impaired GSIS and elevated glucose level were observed in Isl1E283D KI mice while expression of Ins2 and other ISL1 target genes Mafa, Pdx1, Slc2a2 and the interacting protein NeuroD1 were downregulated in isolated islets. Transcriptional activity of the Isl1E283D mutation for Ins2 was reduced by 59.3%, and resulted in a marked downregulation of Ins2 expression when it was overexpressed in INS-1 cells, while overexpression of Isl1WT led to an upregulation of Ins2 expression. CONCLUSIONS/INTERPRETATION: Isl1E283D mutation reduces insulin expression and secretion by regulating insulin and other target genes, as well as its interacting proteins such as NeuroD1, leading to the development of glucose intolerance in the KI mice, which recapitulated the human diabetic phenotype. This study identified and highlighted the Isl1E283D mutation as a novel causative factor for type 2 diabetes, and suggested that targeting transcription factor ISL1 could offer an innovative avenue for the precise treatment of human type 2 diabetes.

Forced LMX1A expression induces dorsal neural fates and disrupts patterning of human embryonic stem cells into ventral midbrain dopaminergic neurons.

The differentiation of human pluripotent stem cells into ventral mesencephalic dopaminergic (DA) fate is relevant for the treatment of Parkinson's disease. Shortcuts to obtaining DA cells through direct reprogramming often include forced expression of the transcription factor LMX1A. Although reprogramming with LMX1A can generate tyrosine hydroxylase (TH)-positive cells, their regional identity remains elusive. Using an in vitro model of early human neural tube patterning, we report that forced LMX1A expression induced a ventral-to-dorsal fate shift along the entire neuroaxis with the emergence of roof plate fates despite the presence of ventralizing molecules. The LMX1A-expressing progenitors gave rise to grafts containing roof plate-derived choroid plexus cysts as well as ectopically induced TH-positive neurons of a forebrain identity. Early activation of LMX1A prior to floor plate specification was necessary for the dorsalizing effect. Our work suggests using caution in employing LMX1A for the induction of DA fate, as this factor may generate roof plate rather than midbrain fates.

miR-652-3p Suppressed the Protective Effects of Isoflurane Against Myocardial Injury in Hypoxia/Reoxygenation by Targeting ISL1.

This research is concentrated on investigating the role and mechanism of miR-652-3p in the protective effects of isoflurane (ISO) against myocardial ischemia-reperfusion (I/R) injury. H9c2 cells underwent pretreatment with varying concentrations of ISO, and subsequently, a hypoxia/reoxygenation (H/R) model was constructed. The levels of miR-652-3p, ISL LIM homeobox 1 (ISL1), and inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) were evaluated through reverse transcription polymerase chain reaction (RT-qPCR). Enzyme-linked immunosorbent assay was employed to investigate concentrations of myocardial injury markers, such as creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI). Cell counting kit-8 was used to evaluate cell viability, while flow cytometry was utilized to measure apoptosis. Additionally, a dual luciferase reporter assay was conducted to validate the targeting relationship between ISL1 and miR-652-3p. Herein, we confirmed that the level of miR-652-3p was gradually increased with prolonged hypoxia; nevertheless, this increase was suppressed by ISO pretreatment (P < 0.05). Additionally, ISO pretreatment prevented the decrease in cell viability, increase in apoptosis, and overproduction of IL-6, TNF-α, CK-MB, and cTnI induced by H/R (P < 0.05). However, the inhibitory effects of ISO were counteracted by the increased levels of miR-652-3p (P < 0.05). ISL1 is a potential target of miR-652-3p. H/R induction suppressed ISL1 levels compared to the control, but ISO treatment increased its expression (P < 0.05). Overexpression of ISL1 inhibited the elimination of the protective effect of ISO on myocardial damage induced by the elevation of miR-652-3p (P < 0.05). The findings of this research confirm that miR-652-3p attenuated the protective effect of ISO on cardiomyocytes in myocardial ischemia by targeting ISL1.

A global gene regulatory program and its region-specific regulator partition neurons into commissural and ipsilateral projection types.

Understanding the genetic programs that drive neuronal diversification into classes and subclasses is key to understand nervous system development. All neurons can be classified into two types: commissural and ipsilateral, based on whether their axons cross the midline or not. However, the gene regulatory program underlying this binary division is poorly understood. We identified a pair of basic helix-loop-helix transcription factors, Nhlh1 and Nhlh2, as a global transcriptional mechanism that controls the laterality of all floor plate-crossing commissural axons in mice. Mechanistically, Nhlh1/2 play an essential role in the expression of Robo3, the key guidance molecule for commissural axon projections. This genetic program appears to be evolutionarily conserved in chick. We further discovered that Isl1, primarily expressed in ipsilateral neurons within neural tubes, negatively regulates the Robo3 induction by Nhlh1/2. Our findings elucidate a gene regulatory strategy where a conserved global mechanism intersects with neuron class-specific regulators to control the partitioning of neurons based on axon laterality.

Proximal tubular FHL2, a novel downstream target of hypoxia inducible factor 1, is a protector against ischemic acute kidney injury.

Four-and-a-half LIM domains protein 2 (FHL2) is an adaptor protein that may interact with hypoxia inducible factor 1α (HIF-1α) or ß-catenin, two pivotal protective signaling in acute kidney injury (AKI). However, little is known about the regulation and function of FHL2 during AKI. We found that FHL2 was induced in renal tubular cells in patients with acute tubular necrosis and mice model of ischemia-reperfusion injury (IRI). In cultured renal proximal tubular cells (PTCs), hypoxia induced FHL2 expression and promoted the binding of HIF-1 to FHL2 promoter. Compared with control littermates, mice with PTC-specific deletion of FHL2 gene displayed worse renal function, more severe morphologic lesion, more tubular cell death and less cell proliferation, accompanying by downregulation of AQP1 and Na, K-ATPase after IRI. Consistently, loss of FHL2 in PTCs restricted activation of HIF-1 and ß-catenin signaling simultaneously, leading to attenuation of glycolysis, upregulation of apoptosis-related proteins and downregulation of proliferation-related proteins during IRI. In vitro, knockdown of FHL2 suppressed hypoxia-induced activation of HIF-1α and ß-catenin signaling pathways. Overexpression of FHL2 induced physical interactions between FHL2 and HIF-1α, ß-catenin, GSK-3ß or p300, and the combination of these interactions favored the stabilization and nuclear translocation of HIF-1α and ß-catenin, enhancing their mediated gene transcription. Collectively, these findings identify FHL2 as a direct downstream target gene of HIF-1 signaling and demonstrate that FHL2 could play a critical role in protecting against ischemic AKI by promoting the activation of HIF-1 and ß-catenin signaling through the interactions with its multiple protein partners.

Lhx2 promotes axon regeneration of adult retinal ganglion cells and rescues neurodegeneration in mouse models of glaucoma.

The axons of retinal ganglion cells (RGCs) form the optic nerve, transmitting visual information from the eye to the brain. Damage or loss of RGCs and their axons is the leading cause of visual functional defects in traumatic injury and degenerative diseases such as glaucoma. However, there are no effective clinical treatments for nerve damage in these neurodegenerative diseases. Here, we report that LIM homeodomain transcription factor Lhx2 promotes RGC survival and axon regeneration in multiple animal models mimicking glaucoma disease. Furthermore, following N-methyl-D-aspartate (NMDA)-induced excitotoxicity damage of RGCs, Lhx2 mitigates the loss of visual signal transduction. Mechanistic analysis revealed that overexpression of Lhx2 supports axon regeneration by systematically regulating the transcription of regeneration-related genes and inhibiting transcription of Semaphorin 3C (Sema3C). Collectively, our studies identify a critical role of Lhx2 in promoting RGC survival and axon regeneration, providing a promising neural repair strategy for glaucomatous neurodegeneration.

LIM homeobox 8 reduced apoptosis and promoted periodontal tissue regeneration function of dental pulp stem cells.

Stem cell-mediated tissue regeneration is a promising strategy for repairing tissue defects and functional reconstruction in periodontitis, a common disease that leads to the loss of alveolar bone and teeth. However, stem cell apoptosis, widely observed during tissue regeneration, impairs its efficiency. Therefore, the regulation of stem cell apoptosis is critical for improving regeneration efficiency. The LIM homeobox 8 gene LHX8, belongs to the LIM homeobox family, which was involved in tooth morphogenesis. Here, we found that LHX8 was significantly expressed in dental pulp. LHX8 knockdown significantly increased dental pulp mesenchymal stem cells (DPSCs) apoptosis, as confirmed by RT-PCR, western blotting, flow cytometry, and transmission electron microscopy. Additionally, LHX8 overexpression inhibited apoptosis and enhanced the osteo/odontogenic differentiation potential of hDPSCs in vitro. Furthermore, LHX8-overexpression could enhance the periodontal tissue regeneration efficiency of hDPSCs in mice with periodontitis. In conclusion, the present study indicates that LHX8 inhibits stem cell apoptosis and promotes functional tissue formation in stem cell-based tissue regeneration engineering, suggesting a new therapeutic target to increase the efficacy of periodontal tissue regeneration.

Structural domain in the Titin N2B-us region binds to FHL2 in a force-activation dependent manner.

Titin N2B unique sequence (N2B-us) is a 572 amino acid sequence that acts as an elastic spring to regulate muscle passive elasticity. It is thought to lack stable tertiary structures and is a force-bearing region that is regulated by mechanical stretching. In this study, the conformation of N2B-us and its interaction with four-and-a-half LIM domain protein 2 (FHL2) are investigated using AlphaFold2 predictions and single-molecule experimental validation. Surprisingly, a stable alpha/beta structural domain is predicted and confirmed in N2B-us that can be mechanically unfolded at forces of a few piconewtons. Additionally, more than twenty FHL2 LIM domain binding sites are predicted to spread throughout N2B-us. Single-molecule manipulation experiments reveals the force-dependent binding of FHL2 to the N2B-us structural domain. These findings provide insights into the mechano-sensing functions of N2B-us and its interactions with FHL2.

ERN1 knockdown modifies the hypoxic regulation of homeobox gene expression in U87MG glioblastoma cells.

OBJECTIVE.: Homeobox genes play an important role in health and disease including oncogenesis. The present investigation aimed to study ERN1-dependent hypoxic regulation of the expression of genes encoding homeobox proteins MEIS (zinc finger E-box binding homeobox 2) and LIM homeobox 1 family, SPAG4 (sperm associated antigen 4) and NKX3-1 (NK3 homeobox 1) in U87MG glioblastoma cells in response to inhibition of ERN1 (endoplasmic reticulum to nucleus signaling 1) for evaluation of their possible significance in the control of glioblastoma growth. METHODS.: The expression level of homeobox genes was studied in control (transfected by vector) and ERN1 knockdown U87MG glioblastoma cells under hypoxia induced by dimethyloxalylglycine (0.5 mM for 4 h) by quantitative polymerase chain reaction and normalized to ACTB. RESULTS.: It was found that hypoxia down-regulated the expression level of LHX2, LHX6, MEIS2, and NKX3-1 genes but up-regulated the expression level of MEIS1, LHX1, MEIS3, and SPAG4 genes in control glioblastoma cells. At the same time, ERN1 knockdown of glioblastoma cells significantly modified the sensitivity of all studied genes to a hypoxic condition. Thus, ERN1 knockdown of glioblastoma cells removed the effect of hypoxia on the expression of MEIS1 and LHX1 genes, but increased the sensitivity of MEIS2, LHX2, and LHX6 genes to hypoxia. However, the expression of MEIS3, NKX3-1, and SPAG4 genes had decreased sensitivity to hypoxia in ERN1 knockdown glioblastoma cells. Moreover, more pronounced changes under the conditions of ERN1 inhibition were detected for the pro-oncogenic gene SPAG4. CONCLUSION.: The results of the present study demonstrate that hypoxia affected the expression of homeobox genes MEIS1, MEIS2, MEIS3, LHX1, LHX2, LHX6, SPAG4, and NKX3-1 in U87MG glioblastoma cells in gene-specific manner and that the sensitivity of all studied genes to hypoxia condition is mediated by ERN1, the major pathway of the endoplasmic reticulum stress signaling, and possibly contributed to the control of glioblastoma growth. A fundamentally new results of this work is the establishment of the fact regarding the dependence of hypoxic regulation of SPAG4 gene expression on ER stress, in particular ERN1, which is associated with suppression of cell proliferation and tumor growth.

Higher-order thalamocortical circuits are specified by embryonic cortical progenitor types in the mouse brain.

The sensory cortex receives synaptic inputs from both first-order and higher-order thalamic nuclei. First-order inputs relay simple stimulus properties from the periphery, whereas higher-order inputs relay more complex response properties, provide contextual feedback, and modulate plasticity. Here, we reveal that a cortical neuron's higher-order input is determined by the type of progenitor from which it is derived during embryonic development. Within layer 4 (L4) of the mouse primary somatosensory cortex, neurons derived from intermediate progenitors receive stronger higher-order thalamic input and exhibit greater higher-order sensory responses. These effects result from differences in dendritic morphology and levels of the transcription factor Lhx2, which are specified by the L4 neuron's progenitor type. When this mechanism is disrupted, cortical circuits exhibit altered higher-order responses and sensory-evoked plasticity. Therefore, by following distinct trajectories, progenitor types generate diversity in thalamocortical circuitry and may provide a general mechanism for differentially routing information through the cortex.