Cell and Tissue Research最新文献

During postnatal development of the rat epididymis, a change in the expression of gap junction proteins, or connexins (Cxs), occurs, in which Gjb2 (Cx26) and Gja1 (Cx43) levels in the proximal epididymis are decreased, while Gjb1 (Cx32), Gjb4 (Cx30.3) and Gjb5 (Cx31.1) levels increase. The mechanism(s) responsible for the switch in Cx expression is unknown. The aim of this study is to identify the mechanisms responsible for the decrease in GJB2 protein levels and the increase in other Cxs during postnatal development. Results indicate that decreased Gjb2 expression for 48 h does not alter the expression of other Cxs in RCE-1 principal cells, suggesting a lack of compensatory expression. Sequence analysis of both Gjb2 and Gjb1 promoters identified common multiple response elements to steroid hormones. Using RCE-1 cells, we observed that dexamethasone increased Gjb2 mRNA levels by twofold after 48 h, while estradiol had no effect. Orchidectomy in rats resulted in a significant increase in GJB2 and decreased GJB1 in the caput and corpus epididymidis. Changes in Cxs protein levels were prevented by testosterone in orchidectomized rats. Similar results were observed in the prostate, another androgen-receptive organ. LNCaP cells, which are androgen-responsive, showed that exogenous dihydrotestosterone (DHT) decreased Gjb2 mRNA levels by approximately 50% concomitant with a 1.5-fold increase in Gjb1 levels. Using a GJB1 promoter construct we showed that DHT could induce transactivation of the luciferase transgene, while transactivation of two GJB2 promoters were unaltered. Results indicate that androgens and glucocorticoids regulate the expression of epididymal Cxs.

The olfactory organ of tetrapods, with few exceptions, comprises the main and accessory organs: olfactory epithelium (OE) and vomeronasal organ (VNO). Unlike tetrapods, teleost fish lack a VNO. However, lungfish, a type of sarcopterygian fish closely related to tetrapods, possesses a lamellar OE similar to the OE of teleosts and a recess epithelium (RecE) resembling the amphibian VNO. The RecE has been hypothesized as a primordial VNO. Olfactory receptors in tetrapods are distinctively expressed in the OE and VNO. For instance, type 2 vomeronasal receptors (V2Rs) in Xenopus are categorized into those exclusively expressed in the OE and those solely expressed in the VNO. It remains unclear whether V2Rs are differentially expressed between the lamellar OE and RecE in lungfish. This study investigated V2R expression in the lamellar OE and RecE of the African lungfish, Protopterus annectens. P. annectens V2Rs were categorized into three groups: those exclusively expressed in the lamellar OE, those exclusively expressed in the RecE, and those expressed in both the lamellar OE and RecE. V2Rs exclusively expressed in the RecE and those expressed in both the lamellar OE and RecE formed a distinct clade in the phylogenetic tree, whereas others were solely expressed in the lamellar OE. These findings suggest that lungfish V2R expression represents an intermediate stage toward complete segregation between V2Rs expressed in the OE and those expressed in the VNO.

Sustained or chronic inflammation in the placenta can result in placental insufficiency, leading to adverse reproductive outcomes such as pregnancy loss. Branched-chain amino acid transaminase 1 (BCAT1) expresses in the placenta and is involved in the pathological inflammatory response, but its role in recurrent miscarriage (RM) has not been fully investigated. In the present study, we delved into the effects of BCAT1 on trophoblast inflammation induced by lipopolysaccharide (LPS) and a mouse model of pregnancy loss induced by LPS. In vitro, after the HTR-8/SVneo cells were treated with LPS and BCATc inhibitor 2 (a selective BCAT inhibitor), the cell apoptosis was verified by TUNEL assay, and the activity of caspase-3 and caspase-9 was detected. Real-time PCR, enzyme-linked immunosorbent assay (ELISA), and immunofluorescence (IF) were used to determine the expression of inflammatory cytokines (TNF-α, IL-6, and IL-1β) and inflammasomes (NLRP3 and ASC) in LPS-treated trophoblast cells. Western blot analysis was performed to verify the expression of phospho-IκBα (p-IκBα) in cells and NF-κB p65 in the nuclei. IF staining was used to detect the nuclear translocation of NF-κB p65. The DNA binding activity of NF-κB was detected by an electrophoretic mobility shift assay (EMSA). The results demonstrated that inhibition of BCAT1 reduced trophoblast apoptosis, suppressed the release of proinflammatory cytokines, and prevented NLRP3 inflammasome activation in response to LPS. Additionally, BCAT1 inhibition blocked the activation of the NF-κB pathway in trophoblasts. This study highlights the potential therapeutic role of targeting BCAT1 in preventing adverse reproductive outcomes associated with chronic placental inflammation.

FMR1 autosomal homolog 1 (FXR1) is an RNA-binding protein that belongs to the Fragile X-related protein (FXR) family. FXR1 is critical for development, as its loss of function is intolerant in humans and results in neonatal death in mice. Although FXR1 is expressed widely including the brain, functional studies on FXR1 have been mostly performed in cancer cells. Limited studies have demonstrated the importance of FXR1 in the brain. In this review, we will focus on the roles of FXR1 in brain development and pathogenesis of brain disorders. We will summarize the current knowledge in FXR1 in the context of neural biology, including structural features, isoform diversity and nomenclature, expression patterns, post-translational modifications, regulatory mechanisms, and molecular functions. Overall, FXR1 emerges as an important regulator of RNA metabolism in the brain, with strong implications in neurodevelopmental and psychiatric disorders.

We have analyzed the organization of the microtubule system in photoreceptor cells and pigment cells within the adult Drosophila compound eye. Immunofluorescence localization of tubulin and of Short stop, a spectraplakin that has been reported to be involved in the anchorage of microtubule minus ends at the membrane, suggests the presence of non-centrosomal microtubule-organizing centers at the distal tip of the visual cells. Ultrastructural analyses confirm that microtubules emanate from membrane-associated plaques at the site of contact with cone cells and that all microtubules are aligned in distal-proximal direction within the photoreceptor cells. Determination of microtubule polarities demonstrated that about 95% of the microtubules in photoreceptor cells are oriented with their plus end in the direction of the synapse. Pigment cells in the eye contain only microtubules aligned in distal-proximal direction, with their plus end pointing towards the retinal floor. There, two populations of microtubules can be distinguished, single microtubules and bundled microtubules, the latter associated with actin filaments. Whereas microtubules in both photoreceptor cells and pigment cells are acetylated and mono/bi-glutamylated on α-tubulin, bundled microtubules in pigment cells are apparently also mono/bi-glutamylated on β-tubulin, providing the possibility of binding different microtubule-associated proteins.

Although the liver of the lamprey, a group of cyclostomes that diverged the earliest among vertebrates, has abundant bile ducts in the larval stage, which degenerate during metamorphosis, there is no comparative study on its architecture with other early diverged vertebrates in terms of the morphological evolution of vertebrate livers. The present study was undertaken to compare the characteristics of the brook lamprey liver with those of the hagfish and banded houndshark, which have the portal triad type liver architecture, and to discuss its evolution. Although the liver of the brook lamprey had two-cell cords of hepatocytes lined by sinusoids in the ammocoetes larval stage, intrahepatic bile ducts around portal veins penetrated into the liver parenchyma with convolution and gradual reduction in diameter. They also faced dilated sinusoids. The epithelial cells had characteristic intercellular spaces. These characteristics were distinct from those of bile ducts in the hagfish and banded houndshark livers. Although the liver architectures of the hagfish and banded houndshark were similar, the latter penetrated the intrahepatic bile ducts more deeply along the portal veins than the former, in which intrahepatic bile ducts were restricted near the hilum. After metamorphosis, bile ducts degenerated in brook lampreys. These data indicate that the liver architecture of the ammocoetes larva is unique in the parenchymal distribution of bile ducts, their sinusoidal facing, and morphology among extant vertebrates. The periportal distribution of intrahepatic biliary structures may have been established prior to the divergence of the cyclostomes and gnathostomes.

The innervation of the antennal heart of the cockroach Periplaneta americana was studied with immunocytochemical techniques on both the light and electron microscopic levels. The antennal heart is innervated by two efferent systems, both using one biogenic amine in combination with neuropeptides. In one, we found co-localization of serotonin with proctolin and allatostatin. These fibers most likely originate from paired neurons located in the suboesophageal ganglion. In the second system, we found octopamine co-localized with the short neuropeptide F. The source of this second system is dorsal unpaired median (DUM) neurons, also located in the suboesophageal ganglion. The possible effects of these neuromediators on different targets are discussed.

The Kupffer cell was first discovered by Karl Wilhelm von Kupffer in 1876, labeling them as "Sternzellen." Since their discovery as the primary macrophages of the liver, researchers have gradually gained an in-depth understanding of the identity, functions, and influential role of Kupffer cells, particularly in infection. It is becoming clear that Kupffer cells perform important tissue-specific functions in homeostasis and disease. Stationary in the sinusoids of the liver, Kupffer cells have a high phagocytic capacity and are adept in clearing the bloodstream of foreign material, toxins, and pathogens. Thus, they are indispensable to host defense and prevent the dissemination of bacteria during infections. To highlight the importance of this cell, this review will explore the history of the Kupffer cell in the context of infection beginning with its discovery to the present day.

Infections are common in patients with diabetes. Moreover, increasing incidence of antibiotic resistance impedes the complete bacterial clearance and calls for alternative treatment strategies. Along with antibacterial resistance, compromised host conditions create a favorable condition for the disease progression. In particular, cell junction proteins are of major importance as they contribute to a tight cell barrier, protecting against invading pathogens. However, the impact of high glucose on cell junction proteins has received little attention in the urinary bladder but merits closer investigation. Here, we report that during diabetes the expression of cell junction protein, claudin 14 is compromised in the human urine exfoliated cells and in the urinary bladder of type 2 diabetic mouse. Further in vitro analysis confirmed a direct correlation of lower intracellular calcium levels with claudin 14 expression in high glucose-treated human uroepithelial cells. Moreover, external calcium supplementation in high glucose-treated cells significantly affected the cell migration and restored the claudin 14 expression through focal adhesion and β-1 integrins. Strengthening the epithelial barrier is essential, especially in individuals with diabetes where basal calcium levels could contribute.

In goldfish, spinal cord injury triggers the formation of a fibrous scar at the injury site. Regenerating axons are able to penetrate the scar tissue, resulting in the recovery of motor function. Previous findings suggested that regenerating axons enter the scar through tubular structures surrounded by glial elements with laminin-positive basement membranes and that glial processes expressing glial fibrillary acidic protein (GFAP) are associated with axonal regeneration. How glia contribute to promoting axonal regeneration, however, is unknown. Here, we revealed that glial processes expressing vimentin or brain lipid-binding protein (BLBP) also enter the fibrous scar after spinal cord injury in goldfish. Vimentin-positive glial processes were more numerous than GFAP- or BLBP-positive glial processes in the scar tissue. Regenerating axons in the scar tissue were more closely associated with vimentin-positive glial processes than GFAP-positive glial processes. Vimentin-positive glial processes co-expressed matrix metalloproteinase (MMP)-14. Our findings suggest that vimentin-positive glial processes closely associate with regenerating axons through tubular structures entering the scar after spinal cord injury in goldfish. In intact spinal cord, ependymo-radial glial cell bodies express BLBP and their radial processes express vimentin, suggesting that vimentin-positive glial processes derive from migrating ependymo-radial glial cells. MMP-14 expressed in vimentin-positive glial cells and their processes might provide a beneficial environment for axonal regeneration.