Neonatal hypothyroidism causes delayed sertoli cell maturation in rats treated with propylthiouracil: Evidence that the sertoli cell controls testis growth

Background: The testes of rats treated neonatally with propylthiouracil (PTU) grow to almost twice their normal size. The cause of testicular enlargement has been suggested to be the result of delayed maturation of Sertoli cells, allowing Sertoli cell division to occur beyond the 15th postnatal day, the commonly recognized cutoff date for Sertoli cell divisions. It has been shown that an increased population of Sertoli cells in postnatal development supports increased numbers of germ cells in adult animals. After examining developing rats treated neonatally with PTU, we hypothesized that an approximate 10-day delay in maturation was occurring and proceeded to test this hypothesis experimentally. Thus the purpose of this report was to determine if a 10-day delay in maturation could explain the increased numbers of Sertoli cells and increased testis size in PTU-treated animals. Methods: Both control animals and animals treated neonatally with PTU N = 5/group were sacrificed at 15 and 25 days of age and prepared for electron microscopy. Results: Micrographs show and morphometric ultrastructural analysis of numerous parameters demonstrated at the 95% probability level that Sertoli cells from 25-day-old PTU animals are not different in size and most constituents (volume and surface area) from 15-day-old control animals and are less mature than 25-day-old control animals. Mitosis of Sertoli cells was observed in PTU-treated animals in 25-day-old animals but not in agematched controls. The number of Sertoli cells in 25-day-old PTU-treated animals is significantly increased over age-matched controls. Micrographs show the presence of immature Sertoli cell nuclei in 25-day-old animals receiving PTU as well as increased germ cell degeneration in this group. Sertoli cell tight junction formation is also delayed in PTU-treated animals as compared with controls. Conclusions: Together, the data show that delayed maturation of Sertoli cells occurs in treated animals that corresponds to a minimum of 10 developmental days. In the immature state, Sertoli cells continue to divide. Data presented herein and published data related to PTU treatment indicate that delayed maturation of the Sertoli cell results in delayed maturation and proliferation of other testicular cell types. From this and from published data, the hypothesis is presented that the Sertoli cell is responsible for the overall control of testis development. © 1995 Wiley-Liss, Inc.     

The efficacy of novel B cell biologics as the future of SLE treatment: A review

Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disease with wide ranging multi-systemic effects. Current understanding centralises B cells in SLE pathogenesis with clinical features resulting from autoantibody formation, immune complex deposition, antigen presentation and cytokine activation. Existing standard of care therapies generates adverse side effects; secondary to corticosteroid use and untargeted immunosuppression. The inability to uphold remission and abolish the disease process, in addition to the increasing numbers of patients seen with refractory disease with these therapies, has provoked the development of novel B cell biologics targeting specific pathogenic pathways fundamental to the SLE disease process.     

Crystalloids of actin-like filaments in the sertoli cell of the swine testis

Normal swine testes, congenital cryptorchid swine testes, and normal human testes were exposed to HMM (heavy meromyosin) after either glycerination or saponin treatment in order to determine whether the fine filaments composing the crystalloids in the Sertoli cells are actin-like. The microfilaments of the crystalloids in the Sertoli cells of the cryptorchid swine testes bind HMM to form arrowhead complexes. Short bundles of microfilaments observed in the basal part of the Sertoli cells in both normal and cryptorchid testes also bind HMM. Similar bundles of HMM-bound filaments are observed in the vicinity of spermatocytes. The periodicity of the arrowhead complexes is about 35 nm, and all arrowheads on a given filament point in the same direction. In addition, the polarity of the HMM-bound filaments in a given crystalloid or bundle is uni-directional. A mechanism for the formation of the swine crystalloids has been suggested by Toyama (′75), and the results of this study strongly support this hypothesis. Fine filaments of Charcot-Boettcher's crystalloid in human Sertoli cells did not bind HMM. Therefore the fine filaments of the human crystalloid are not actin-like in nature.     

An adolescent with large cell calcifying sertoli cell tumor of the testis and undiagnosed Carney Complex: A case report

Carney Complex (CNC) is a rare autosomal dominant condition with characteristic clinical presentation, tumor development, and unique genetic mutation. We present a unique case and literature review of CNC in which two neoplasms characteristic of this complex were initially diagnosed through cytological fine needle aspirate specimens, leading to the identification of CNC, with subsequent surgical and cytogenetic confirmation. Diagn. Cytopathol. 2017;45:634–639. © 2017 Wiley Periodicals, Inc.     

The sertoli cell junctional complex: Structure and permeability to filipin in the neonatal and adult guinea pig

The development and maintenance of the Sertoli cell junctional complex were investigated in prepubertal and adult guinea pigs. To correlate the structure of the blood-testis barrier with its permeability, the polyene antibiotic filipin (a cholesterol-binding agent of low molecular weight: 570.70) was added to the fixative as a tracer visible in freeze-fracture replicas. Discontinuous zonules, intermediate junctions (i.e., adhering fasciae) and gap junctions all proved permeable to filipin in the two age groups. Only the continuous occluding zonules characteristic of the adult guinea pig's testis were impermeable to the tracer. In pubertal animals, the establishment of the blood-testis barrier coincided with the completion of the junctional strands in occluding zonules. The formation of occluding zonules was similar in the newborn and the adult. In the adult, the Sertoli cell junctional complexes contained three types of cell junctions: occluding, adhering, and gap junctions. The sequence of occluding and adhering junctions from the base to the apex of the epithelium was the reverse of that demonstrated in most epithelia. The impermeable continuous occluding zonules at the base showed parallel patterns of uninterrupted junctional strands, whereas the permeable discontinuous zonules found higher in the epithelium showed a meandering pattern of broken strands. Our observations indicate that (1) Sertoli cell junctional complexes form near the young germinal cells at the base of the seminiferous epithelium and break down near the older germinal cells toward the apex; (2) the various patterns and orientations of the junctional strands reflect, respectively, the different stages of disintegration of the occluding zonules and the conformation of the mature Sertoli cell to the irregular contours of the germinal cells; (3) there is no relationship between permeability and junctional strand orientation; and (4) the cellular contacts between Sertoli cells and germinal cells situated below the blood-testis barrier may represent the early stages of formation of junctional elements which ultimately become incorporated into the Sertoli cell junctional complex.     

Molecular-cytogenetic characterisation of sex cord-stromal tumours: CGH analysis in sertoli cell tumours of the testis

Sertoli cell tumours (SCT) are rare and poorly explored neoplasias, and the genetic features of these uncommon tumours are largely unknown. Data about chromosomal aberrations in human SCT of the testis are very rare. We present in this paper the first molecular-cytogenetic study of SCT of the testis. DNA was isolated from paraffin-embedded tumour material from 11 patients with unilateral SCT. We used comparative genomic hybridisation to investigate changes in DNA copy number. The detected DNA imbalances showed variation from case to case, indicating a high genetic heterogeneity. Chromosomal aberrations were detected in 9 of the 11 tumours evaluated, with 13 losses versus 14 gains. The most frequent aberrations detected were gain of chromosome X (5 of 11 cases) followed by losses of entire or part of chromosomes 2 and 19 in three cases. This study suggests a high variability in histomorphological and genetic patterns. Only gain of the entire chromosome X seems to be a frequent aberration in these tumours. Further studies of these tumour types are necessary to clarify the significance of chromosomal alterations in carcinogenesis of SCT.     

Birth-weight as a risk factor for cancer in adulthood: the stem cell perspective

The 'stem cell burden' hypothesis represents a plausible explanation for the association between birth-weight and the risk of breast cancer in adulthood. The size of the overall stem cell pool would be expected to affect organ size and consequently birth-weight, making birth-weight a proxy for the overall number of fetal stem cells. As stem cells are self-renewing, the greater their number is at birth, the higher will be the chance that one of them will undergo carcinogenesis over the years. To investigate the correlation between birth-weight and stem cell burden, we examined the cord blood hematopoietic CD34+ stem cell population as an indicator of the overall fetal stem cell number. We measured both the CD34+ level (by flow cytometry) and the CD34+ proliferative potential (by the GM-CFU culture), in a sample of 1037 healthy newborn cord blood donors. We found that heavier babies had a significantly greater CD34+ stem cell concentration (p<0.001) and a higher GM-CFU number than lighter babies (p<0.001). Thus, a high birth-weight was positively associated with a high concentration of CD34+ stem cells and also with a qualitatively higher "stemness" of this pool. Therefore, our data support the theory that birth-weight reflects the number of fetal stem cells.     

Cyclic modulation of sertoli cell junctional complexes in a seasonal breeder: The mink (Mustela vison)

The development and modulation of Sertoli cell junctions was studied in newborn and adult mink during the active and inactive spermatogenic phases. The techniques used were electron microscopy of freeze-fractured replicas and thin sections of tissues infused with horseradish peroxidase as a junction permeability tracer. In the newborn, freeze-fractured developing junctions had either spherical or fibrillar particles. In addition, Junctional domains where particles were associated preferentially with the E-face, and others where particles were associated preferentially with the P-face, were found developing either singly or conjointly within a given membrane segment, thus yielding a heterogeneous Junctional segment. Coincidently with the development of a tubular lumen and the establishment of a competent blood-testis barrier, Junctional strands were composed primarily of particulate elements associated preferentially with the E-face. In adult mink during active spermatogenesis, cell junctions were found on the entire lateral Sertoli cell plasma membrane from the basal to the luminal pole of the cell. In the basal third of the Sertoli cell, membranous segments that faced a spermatogonium or a migrating spermatocyte displayed forming tight, gap, and adherens junctions. In the middle third, abutting membrane segments localized above germ cells were involved in continuous zonules and in adherens junctions. In the apical or luminal third, the zonules were discontinuous, and the association of Junctional particles with the E-face furrow was lost. Gap junctions increased in both size and numbers. Junctional vesicles that appeared as annular gap and tight-junction profiles in thin sections or as hemispheres in freeze-fracture replicas were present. Reflexive tight and gap junctions were formed through the interaction of plasma membrane segments of the same Sertoli cell. Internalized Junctional vesicles were also present in mature spermatids. During the inactive spermatogenic phase, cell junctions were localized principally in the basal third of the Sertoli cell; Junctional strands resembled those of the newborn mink. During the active spermatogenic phase, continuous zonules were competent in blocking passage of the protein tracer. During the inactive phase the blood-testis barrier was incompetent in blocking entry of the tracer into the seminiferous epithelium. It is proposed that modulation of the Sertoli cell zonules being formed at the base and dismantled at the apex of the seminiferous epithelium follows the direction of germ cell migration and opposes the apicobasal direction of junction formation reported for most epithelia. The arrest of spermatogenesis coincides with dramatic changes in the dynamic modifications of Sertoli cell zonules.     

The immature type of pro-opiomelanocortin cell of the rat anterior pituitary as observed by immunogold electron microscopy

The perinatal development of glandular cells in the rat anterior pituitary producing pro-opiomelanocortin (POMC), the precursor protein of peptide hormones including adrenocorticotropin (ACTH), melanocyte-stimulating hormones (MSH) and endorphins was studied by an immunoelectron microscopic technique using the colloidal gold-antibody method. The POMC cells are classified into the following three types: 1) an immature type, 2) an intermediate type, and 3) a mature type, which correspond to Types III, I and II of the ACTH cells, respectively. The average size of the secretory granules in POMC cells varies widely, measuring 98.6 +/- 8.5 nm in the immature type, 111.4 +/- 6.7 nm in the intermediate type, and 139.3 +/- 23.1 nm in the mature type. The immature type comprises more than 90% of the POMC cells in the late fetal stage, but decreases in number after birth. The intermediate type reaches a peak at 8 days (female) or 33 days (male), while the mature type is that most frequently observed at 45 days, i.e., more than 50-60% of the total POMC cells, when the immature type decreases to about 15%.     

A novel use of alginate hydrogel as Schwann cell matrix.

The use of bioresorbable conduits supplemented with Schwann cells (SCs) is a promising tissue engineering technique to replace nerve grafting. Alginate hydrogel (AH), as a SC tissue engineering matrix, has many advantages over previously used matrices but has not been evaluated for this purpose. In this study, the viability and proliferation of SCs together with SC function in AH was evaluated in vitro. AlamarBlue cell assay was used to monitor the viability of SCs in AH and compared to SC viability in collagen gel, fibrin glue, hyaluronic acid, Matrigel, and standard culture plate over 5 days in culture. The results showed that the viability and growth of SCs in different matrices over the culture period did not significantly differ to culture plate culture. SC function when suspended in AH was monitored using chick embryo dorsal root ganglia (CDRG) growth assay. Growth of CDRG in AH with or without SCs was compared to CDRG growth without AH matrix. After 3 days in culture, the mean length of neurite sprouting was measured. The results showed that there was neurite growth in AH but was reduced to 43% of control. The neurite growth in AH was, however, enhanced by 170% when SCs were suspended in the gel. In conclusion, AH supported SC viability and function in vitro and may be useful in peripheral nerve tissue engineering in reconstructive procedures.     

A novel approach for the derivation of putative primordial germ cells and sertoli cells from human embryonic stem cells

Using human embryonic stem cells (hESCs), we describe a novel method for the rapid derivation and enrichment of cells that are comparable to primordial germ cells (PGCs) and Sertoli cells. The methodology described is based on modest changes to the growth conditions commonly used to expand hESCs and does not require genetic manipulation or complex three-dimensional culture. Remarkably, we have determined that simply reducing the size of cultured ESC colonies and manipulating the number of feeding cycles, results in the rapid emergence of cells that are comparable to migratory PGCs. Importantly, these cells can be monitored and purified on the basis of the expression of the chemokine receptor CXCR4. Under more stringent differentiating conditions these cells mature and upregulate the expression of specific germ cell markers. Importantly, this process is accompanied by the development of Sertoli-like support cells. Such cells normally provide trophic support and immunoprotection to developing germ cells and may have significant clinical utility in the prevention of graft rejection. The putative Sertoli-germ cell cocultures generated in this study may ultimately be developed to study and manipulate interactions and processes involved in human gametogenesis.     

转基因小鼠高表达的FasL对Sertoli细胞免疫调节功能的影响

目的 :研究转基因小鼠高表达的FasL对Sertoli细胞在睾丸局部感染时的免疫调节作用的影响。方法 :将溶脲脲原体 (UU)分别注入FasL转基因及野生型小鼠膀胱 ,模拟上行性感染的途径。分别在感染后 1、2和 3wk处死小鼠 ,分离睾丸组织观察其病理变化 ,并用免疫组化染色法比较UU感染前后 ,Ser toli细胞上FasL和TGF β、IL 1α、IL 6的表达及分泌格局的差异。从野生型小鼠睾丸组织中分离高纯度的Sertoli细胞 ,与未感染UU的对照组相比 ,观察UU感染后FasL Sertoli细胞介导Fas Jurkat细胞的凋亡能力的变化。结果 :UU感染组的转基因小鼠 ,睾丸组织发生的病理改变比野生型更为明显 ;两种小鼠感染后Sertoli细胞分泌的调节因子变化格局不同 ;感染后Sertoli细胞对Jurkat细胞的杀伤能力增强。结论 :在抗感染免疫中 ,转基因表达的FasL可影响Sertoli细胞分泌细胞因子的格局 ,进而影响睾丸局部的免疫平衡。过高表达的FasL对机体的抗感染应答并非一定有利。     

Relative volume of sertoli cells in monkey seminiferous epithelium: A stereological analysis

Techniques of quantitative stereology have been utilized to determine the relative volume occupied by the Sertoli cells and germ cells in two particular stages (I and VII) of the cycle of the seminiferous epithelium. Sertoli cell volume ranged from 24% in stage I of the cycle to 32% in stage VII. Early germ cells occupied 3.4% in stage I (spermatogonia) and 8.7% in stage VII (spermatogonia and preleptotene spermatocytes). Pachytene spermatocytes occupied 15% (stage I) and 24% (stage VII) of the total volume of the seminiferous epithelium. In stage I the two generations of spermatids comprised 58% of the total epithelium by volume, whereas in stage VII, after spermiation, the acrosome phase spermatids occupied 35% of the total seminiferous epithelial volume.     

A novel family of repetitive DNA sequences amplified site-specifically on the W chromosomes in Neognathous birds

A novel family of repetitive DNA sequences was molecularly cloned from ApaI-digested genomic DNA of two Galliformes species, Japanese quail (Coturnix japonica) and guinea fowl (Numida meleagris), and characterized by chromosome in-situ hybridization and filter hybridization. Both the repeated sequence elements produced intensely painted signals on the W chromosomes, whereas they weakly hybridized to whole chromosomal regions as interspersed-type repetitive sequences. The repeated elements of the two species had high similarity of nucleotide sequences, and cross-hybridized to chromosomes of two other Galliformes species, chicken (Gallus gallus) and blue-breasted quail (Coturnix chinensis). The nucleotide sequences were conserved in three other orders of Neognathous birds, the Strigiformes, Gruiformes and Falconiformes, but not in Palaeognathous birds, the Struthioniformes and Tinamiformes, indicating that the repeated sequence elements were amplified on the W chromosomes in the lineage of Neognathous birds after the common ancestor diverged into the Palaeognathae and Neognathae. They are components of the W heterochromatin in Neognathous birds, and a good molecular cytogenetic marker for estimating the phylogenetic relationships and for clarifying the origin of the sex chromosome heterochromatin and the process of sex chromosome differentiation in birds.     

The red blood cell as a novel regulator of human B‐cell activation

Non‐immune cells are increasingly recognized as important in regulating immunity, but the role of red blood cells (RBC) remains relatively unexplored, despite their abundance in the circulation and a cell surface rich in potential ligands. Here, we determine whether RBC influence the activation state of human B cells. Separation of RBC from peripheral blood mononuclear cells increased B‐cell expression of HLA‐DR/DP/DQ, whilst reconstitution reduced the levels of B‐cell activation markers HLA‐DR/DP/DQ, CD86, CD69 and CD40, as well as decreasing proliferative responses and IgM secretion. Inhibition of B cells required contact with RBC and was abrogated by either removal of sialic acids from RBC or blocking the corresponding lectin receptor CD22 on B cells. Chronic lymphocytic leukaemia B cells express low levels of CD22 and were less susceptible to inhibition by RBC, which may contribute to their activated phenotype. Taken together, the results identify a novel mechanism that may suppress inappropriate responsiveness of healthy B cells whilst circulating in the bloodstream.     

The value of microRNAs as the novel biomarkers for colorectal cancer diagnosis: A meta-analysis

BackgroundNumerous studies have reported that microRNAs (miRNAs) hold great potential as the biomarkers for colorectal cancer (CRC). However, inconsistent results have made it challenging to evaluate their diagnostic performance. Thus, the aim of this meta-analysis was to systematically assess the pooled efficacy of miRNAs for CRC diagnosis.MethodsA search for eligible studies up to October 30, 2019 was conducted using PubMed, Web of Science and EMBASE databases. A random-effects model was used to evaluate the pooled sensitivity and specificity. The summary receiver operator characteristic (SROC) curve and area under the curve (AUC) were calculated to assess the overall diagnostic efficacy.ResultsA total of 3258 CRC patients and 2683 healthy controls were identified in 35 included studies. The overall diagnostic accuracy was as follows: sensitivity, 0.80 [95 % confidence interval (CI) 0.75−0.83]; specificity, 0.80 (95 % CI, 0.75−0.84); positive likelihood ratio (PLR), 4.0 (95 % CI, 3.2−5.0); negative likelihood ratio (NLR), 0.26 (95 % CI, 0.21−0.31); diagnostic odds ratio (DOR), 16 (95 % CI, 11−23); and AUC, 0.87 (95 % CI, 0.83−0.89).ConclusionThe results indicated that miRNAs, particularly serum-derived miRNAs, can serve as the powerful and promising biomarkers for early CRC screening.     

Characteristics of the membrane of the stereocilia and cell apex in cochlear hair cells

Summary Freeze-fracture has been used to examine the membrane of the cell apex and of the stereocilia in cochlear hair cells. The apical (non-stereociliary) membrane of inner hair cells (IHCs) exhibited a lower density of intramembrane particles (IMP) than that of the outer hair cells (OHCs) but in both cell types the apical membrane responded to the effects of filipin. The distribution of IMP and of filipin-induced membrane deformations was uniform over the apical membranes in both IHC and OHC, thus, providing no evidence for local membrane differentiation on the non-stereociliary part of the hair cell apex. The stereociliary membranes of IHC and of OHC differed not only in the density of IMP, but also in their responses to filipin and to tomatin. IHC stereocilia responded intensely to both agents. OHC stereocilia showed a significantly lower density of filipin-induced lesions and appeared almost unaffected by tomatin. This suggests that the OHC stereocilial membrane may be structurally specialized. The membrane at the apical end of stereocilia appeared to be differentiated from the membrane of the stereociliary shaft. The tip region was free of the usual IMP and showed no filipin-induced lesions. The differentiation at the apical end was also apparent in samples which have been rapidly frozen without prior chemical fixation or cryoprotection, showing that the particle-free area was not an artefact induced by glutaraldehyde fixation. Close examination of the membrane at the apical-most tip of the stereocilium revealed the presence of a small number of large particles of 10.5–11.0 nm diameter. The occurrence of membrane differentiation localized to the tip of the stereocilium may be consistent with the suggestion that transduction channels in hair cells are situated at this point.     

Proliferation of sertoli cells in fetal and postnatal rats: A quantitative autoradiographic study

Proliferation of Sertoli cells during fetal and postnatal development of the rat was examined and quantified with light microscope autoradiography. Fetuses in utero were injected subcutaneously with ³H-thymidine. The percentages of Sertoli nuclei that had incorporated label were determined in auto-radiographs from fetuses aged 16 through 21 days of gestation. To compare the degree of Sertoli cell proliferation during fetal development with that occurring after birth, pups were also studied at intervals between the day of birth and 3 weeks of age. For each fetus or pup, at least 500 Sertoli cell nuclei in each of three sections were scored as labeled or unlabeled. These data were subjected to analysis of variance and the Newman-Keuls test. The percentage of Sertoli cells incorporating ³H-thymidine increased progressively from day 16 of gestation onward, to a maximum of 26.8% on day 20, two days before birth. Thereafter, this percentage dropped steadily until, in pups 21 days after birth, no labeled Sertoli cells were detected. These findings highlight the fetal period as the time of greatest expansion of the Sertoli cell population and indicate that, at birth, proliferation of these cells is already on the decline.