Histochemistry and Cell Biology最新文献

Glycan-binding specificity was studied for Jacalin, RCA 120, SBA, PHA-L, PHA-E, WGA, UEA, AAL, LTL, LEL, SNA, DSA, LCA, MAH and Con A, lectins widely used in histochemistry. Oligosaccharide- and polysaccharide-based glycan arrays were applied. Expected specificity was confirmed for only 6 of the 15 lectins and the glycan binding profiles of some lectins were dramatically broader than generally accepted. WGA, LEL and DSA known as chitooligosaccharide-specific, were unexpectedly polyreactive, binding to other glycans with the same affinity as to chitobiose, ABH antigens and oligolactosamines (unsubstituted and sialylated). SBA, in addition to expected binding to glycans with terminal GalNAcα, also had high affinity for the GM1 ganglioside. MAH demonstrated much higher affinity to a variety of sulfated glycans compared to Neu5Acα2-3Galβ1-3GalNAcα. Contrary to the common view, LCA demonstrated the maximum binding to (GlcNAcβ1-2Manα1)₂-3,6-Manβ1-4GlcNAcβ1-4GlcNAc N-glycan, while it had no interaction with corresponding Gal or Neu5Ac terminated versions. This observed polyreactivity of some lectins casts doubt on their use in accurately determining the presence of a specific glycan structure by histochemical studies. However, comparisons of sera from healthy and diseased individuals with help of a lectin array can easily establish differences in glycosylation patterns and presumptive glycan identities, which can later be clarified using more accurate methods of structural analysis.

Sialadenitis is a prevalent salivary gland disease resulting in decreased salivary flow rate. To date, little is known about the exact changes and mechanism of ductal cells in sialadenitis. This study aims to establish an efficient method to identify and isolate ductal cells, thereby facilitating further research on this specific cell type. Immunofluorescence for cytokeratin 13 and cytokeratin 19 was conducted in salivary glands to confirm their specificity as ductal cell markers. The dissected ducts were assessed through PCR and Western blot of cytokeratin 19 and digested by dispase and collagenase. The functionality of the isolated ductal cells was determined by measuring intracellular calcium. Cytokeratin 19 and cytokeratin 13 were expressed in all segments of human ducts. Cytokeratin 19 was limited to ducts excluding granular convoluted tubules in rat and mouse. The purities of the obtained ductal cells were approximately 98% in humans and 93% in rats. Furthermore, intracellular free calcium increased with time and concentration of carbachol treatment. Cytokeratin 19 serves as a dependable marker for identifying ductal cells in salivary glands, except for granular convoluted tubules. Moreover, we have successfully developed an efficient method for isolating ductal cells from salivary glands.

Studies on the contribution of enteric neuropathy and intestinal homeostasis to central nervous system degeneration using animal models have reported varying results. Recently, colonic myenteric plexus degeneration was observed in trimethyltin-treated rats. Further characterization of this animal model is necessary to determine its potential for investigating the relationship between the enteric nervous system and central nervous system degeneration. In this study, trimethyltin-treated rats (8 mg/kg body weight, i.p.) were used to measure colonic function, structure, and possible colon abnormalities. The colonic function was assessed by measuring fecal pellet output and transit time. Hematoxylin and eosin staining and immunohistochemistry were performed to evaluate inflammatory profiles and intestinal epithelial cell homeostasis. The expression of mRNA encoding tight junction proteins was quantified with quantitative PCR to determine colon permeability. Histological examination of the colon revealed mucosal immune cell infiltration, crypt damage, and high iNOS and arginase-1 expression in the mucosal layer of trimethyltin-treated rats. At the same time, trimethyltin induced high expression of iNOS, arginase-1, and GFAP and increased cell death in the colonic myenteric plexus. The low cell proliferation and low goblet cell distribution suggested altered intestinal epithelial cell homeostasis in trimethyltin-treated rats. Trimethyltin also upregulated claudin 1 expression. However, normal colon function was preserved. In conclusion, the results show that trimethyltin induces colon inflammation and cell death in the colonic myenteric plexus, and disrupts intestinal epithelial cell homeostasis. However, the balance between anti-inflammatory and pro-inflammatory responses maintains normal colon function in trimethyltin-treated rats.

Chelidonic acid (ChA) is small molecule capable of inducing the differentiation of mesenchymal stem cells (MSCs) into osteoblasts and the formation of mineralized bone matrix (MBM) both in vitro and in vivo. However, the molecular mechanisms underlying these effects are unknown. Therefore, in silico modelling of potential molecular targets of ChA was performed. ChA was isolated from Saussurea controversa. The ability of ChA to induce in vitro differentiation MSCs into osteoblasts synthesizing MBM was detected using alizarin red staining. ChA osteogenic activity was studied in mice by in situ test of ectopic osteogenesis, using the subcutaneous implantation of syngeneic bone marrow on the calcium phosphate coated titanium plates. DIGEP-Pred web service was used to simulate in silico the effect of ChA on gene expression, and overrepresentation analysis to search for common ontologies and pathways. ChA linearly increased the number of single (R² = 0.92, p = 0.039) and the total areas of MBM sites (R² = 0.96, p = 0.019) in a 21-day MSC culture. Oral administration of ChA led to two to three times improved bone and bone marrow formation in situ. In silico modelling identified 306 genes (including 7 calcium import genes) and 9 signalling pathways potentially involved in ChA osteogenic effect and calcium metabolism in MSCs. In silico analysis revealed a list of key signalling pathways and genes for calcium influx into MSCs and their differentiation into osteoblasts as the first target candidates for studying real gene expression and molecular mechanisms of the ChA osteogenic effects.

In diabetes, tissue repair is impaired, increasing susceptibility to Staphylococcus aureus infections, a pathogen commonly found in wounds. The emergence of S. aureus strains that are highly resistant to antimicrobial agents highlights the urgent need for alternative therapeutic options. One promising candidate is Cramoll (Cratylia mollis seed lectin), known for its immunomodulatory, mitogenic, and healing properties. However, its efficacy in infected diabetic wounds remains unexplored. This study evaluated the effects of topical Cramoll treatment on diabetic wounds infected by S. aureus. Diabetic Swiss mice (induced by streptozotocin) were subjected to an 8-mm wound on the back and subsequently infected with a suspension of multidrug-resistant S. aureus. During the treatment period, the wounds were clinically evaluated for inflammation and the area of injury. After seven days, samples were collected from the wounds to quantify the bacterial load and histopathological and immunological analyses. Wounds infected by S. aureus exhibited more pronounced areas and severity indices, which were significantly reduced by Cramoll treatment (p < 0.05). Histopathological analysis revealed a reduction in inflammatory cells and an increase in revascularization with Cramoll treatment (p < 0.05). Cramoll also promoted greater collagen production compared to controls (p < 0.05). Furthermore, Cramoll treatment significantly reduced the S. aureus load in wounds (p < 0.0001), decreased TNF-α and IL-6 levels in infected wounds, and increased ERK pathway activation (p < 0.05). In conclusion, Cramoll lectin improves the healing of diabetic wounds, and these results contribute to the understanding of Cramoll healing mechanisms, reinforcing its potential as a healing agent in various clinical conditions.

Occasionally, tissue samples cannot be processed completely and are stored under varying conditions for extended periods. This is particularly beneficial in interinstitutional studies where a given research setting may lack the expertise or infrastructure for sample processing, imaging and data analysis. Currently, there is limited literature available on the controlled storage of biological tissues in primary fixatives for fluorescence and electron microscopy. In this contribution, we mimicked various tissue storage scenarios by taking different fixation conditions, storage temperatures and storage durations into account. Rat liver tissue was used for its well-known diversity of cellular ultrastructure and microscopy analysis. Fluorescent labelling of actin, DNA and lipids were employed in conjunction with high-resolution electron microscopy imaging. Herein, we tested three different fixative solutions (1.5% glutaraldehyde, 0.4% glutaraldehyde and 4% formaldehyde and 4% formaldehyde) and stored samples for 1-28 days at room temperature and refrigerator temperature. We found that liver tissue can be stored for up to 2 weeks in a 0.4% glutaraldehyde + 4% formaldehyde fixative solution, while still enabling reliable fluorescent labelling and ultrastructural studies. Ultrastructural integrity was eminent up to 1 month using either glutaraldehyde or formaldehyde fixation protocols. When liver tissue is fixed with a mixture of 0.4% glutaraldehyde and 4% formaldehyde and stored at 4 °C, it retains its capacity for electron microscopy analysis for several years, but loses its capacity for reliable fluorescent labelling studies. In conclusion, we demonstrated that liver tissue can be stored for extended periods enabling profound structure-function analysis across length scales.

Bmi1 is a polycomb protein localized in stem cells and maintains their stemness. This protein is also reported to regulate the expression of various differentiation genes. In this study, to analyze the role of Bmi1 during dentinogenesis, we examined the immunohistochemical localization of Bmi1 during rat tooth development as well as after cavity preparation. Bmi1 localization was hardly detected in the dental mesenchyme at the bud and cap stages. After the bell stage, however, this protein became detectable in preodontoblasts and early odontoblasts just beginning dentin matrix secretion. As dentin formation progressed, Bmi1 immunoreactivity in the odontoblasts decreased in intensity. After cavity preparation, cells lining the dentin and some pulp cells under the cavity were immunopositive for Bmi1 at 4 days. Odontoblast-like cells forming reparative dentin were immunopositive for Bmi1 at 1 week, whereas their immunoreactivity was not detected after 8 weeks. We further analyzed the function of Bmi1 using KN-3 cells, a dental mesenchymal cell line. Overexpression of Bmi1 in KN-3 cells promoted mineralized tissue formation. In contrast, siRNA knockdown of Bmi1 in KN-3 cells reduced alkaline phosphatase activity and the expression of odontoblast differentiation marker genes such as Runx2, osterix, and osteocalcin. Additionally, KN-3 cells transfected with siRNA against Bmi1 showed reduced nuclear transition of β-catenin and expression of phosphorylated-Smad1/5/8. Taken together, these findings suggest that Bmi1 was localized in the odontoblast-lineage cells in their early differentiation stages. Bmi1 might positively regulate their differentiation by accelerating Wnt and BMP signaling pathways.

The multifactorial nature of diabetic wounds necessitates a mixed approach for successful treatment. Compensation of degenerated wound tissue extracellular matrix (ECM) and application of anti-inflammatory and antioxidant agents have been shown to be promising. Here, an attempt was made to fabricate a biocompatible wound dressing from curcumin-incorporated human amniotic membrane (HAM) ECM-derived scaffold to accelerate diabetic wound healing in rats. Therefore, after inducing diabetes, an excisional ischemic wound was created on rat skin, then treatments were administered for a period of 21 days. The main groups were the diabetic animals that received an engraftment of HAM scaffold (HAMS group) and the curcumin-incorporated HAMS (HAMS/β/C group). Evaluation at post-wounding days 7, 14, and 21 indicated that the parameters related to regeneration, including wound closure, volume of new epidermis and dermis, proliferating cells, fibroblasts, blood vessels, collagen deposition, and tensile strength, as well as transcripts of Vegf, bFgf, and Tgf-β genes of the healed wound in both HAMS and HAMS/β/C groups were considerably greater than those of the diabetic group. Conversely, the presence of inflammatory cells, i.e., neutrophils and macrophages, and the transcripts of Tnf-α and Il-1β showed a dramatic decrease in the treated groups relative to the diabetic group. Finally, compared to the HAMS group, considerable differences were found with the HAMS/β/C group in almost all evaluated parameters. Overall, these results suggest that using the complementary or synergistic effects of curcumin and HAMS could be a promising approach to improve diabetic wound healing.

At the beginning of the coronavirus disease 2019 (COVID-19) pandemic, uncertainties about the virus and its dangers during pregnancy caused great uncertainty and fear, especially among pregnant women. New data suggest an increased risk of obstetric complications, including maternal complications, preterm labor, intrauterine growth restriction, hypertensive disorders, stillbirths, gestational diabetes and risk, of neonatal developmental disorders. In addition, preeclampsia (PE)-like syndromes were also induced by severe COVID-19 infection. Therefore, the aim of this study was to investigate the expression of CD68 and CD163 and PD-L1 on placental tissues from acute covid patients, patients who survived a covid-19 infection and normal term controls that are known to be dysregulated in preeclampsia cases. We examined a total of 60 placentas from women that had given birth to female or male offspring in the University Hospital Augsburg. We investigated ten acute COVID-19 females, ten acute COVID-19 males, ten post-COVID-19 females, ten post-COVID-19 males, ten female term controls, and ten male term controls. Immunohistochemical staining against CD68, CD163, and PD-L1 was performed and the expression of the markers was evaluated with an immunoreactive score (percentage score). Identity of CD163- or PD-L1 expressing cells was analyzed by double immune fluorescence analyses. In opposite to PE, CD163 positive maternal macrophages are significantly upregulated in the decidua of male acute COVID-19 placentas. PD-L1 is significantly upregulated on male acute- and post-COVID-19 decidual immune cells and on male post-COVID-19 extravillous trophoblast cells. Surprisingly the observed effects are related to the fetal gender as they were not observed in female offsprings. Further investigation is necessary to analyze especially the imprinting effect of this infection.

Preeclampsia, a severe pregnancy complication linked to defective placentation, poses significant maternal risks and is characterized by dysregulated angiogenic factors, including placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1). Women with HIV/AIDS and receiving ART may face an increased susceptibility to preeclampsia development due to immunological and angiogenic imbalance. This study investigates the immunoexpression of these factors in the context of HIV-associated preeclampsia, utilizing morphometric image analysis. The study cohort comprised 180 women, including 60 normotensive and 120 preeclamptic participants, further stratified by HIV status and gestational age (early-onset PE [EOPE] < 34 weeks and late-onset PE [LOPE] ≥ 34 weeks). Placental bed tissues were immunostained with mouse anti-human sFlt-1 and PlGF antibodies, and the results were analyzed using Zeiss Axio-Vision and GraphPad Prism software. sFlt-1 levels showed no significant overall difference between preeclamptic and normotensive women (p = 0.8661), though slightly increased in the preeclamptic myometrium, independent of HIV status. However, sFlt-1 levels were significantly higher in EOPE compared to both normotensive and LOPE groups. PlGF immunostaining also showed no significant overall difference (p = 0.7387) but was notably lower in preeclamptic pregnancies and significantly higher in EOPE compared to LOPE. HIV status did not significantly impact sFlt-1 or PlGF levels, although sFlt-1 was slightly higher in HIV-negative women, while PlGF was marginally higher in HIV-positive women. These findings highlight the complex role of angiogenic factors in preeclampsia pathophysiology and suggest that antiretroviral therapies (ARTs) may contribute to the dysregulation of these factors due to a heightened immune milieu.