Release of HIV-1 particles from the viral compartment in macrophages requires an associated cytoskeleton and is driven by mechanical constraints

A defining feature of HIV-1 replication in macrophages is that viral assembly occurs at the limiting membrane of a compartment often named VCC (virus-containing compartments) that is connected to the extracellular medium. The newly formed viral progeny pinches of the membrane and accumulates in the lumen of the VCC. While HIV budding has been extensively studied, very little is known about how viral particles present in the lumen of VCC are released in the extracellular medium. Here we show that the actin dynamics are critical for this process by combining ultrastructural analyses, time-lapse microscopy and perturbations of the actin cytoskeleton. We found that jasplakinolide, which stabilizes actin fibres, inhibited viral release from HIV-1-infected macrophages, but not from infected HeLa cells. Furthermore, in jasplakinolide-treated macrophages, VCC became scattered and no longer co-localized with the integrin CD18, nor the phosphorylated form of the focal adhesion kinase PYK2. Inhibition of PYK2 activity in infected macrophages promoted intracellular retention of viral particles in VCC that were no longer connected to the plasma membrane. Finally, we stimulated the rapid release of viral particles from the VCC by subjecting infected macrophages to frustrated phagocytosis. As macrophages spread on IgG-coated glass surfaces, VCC rapidly migrated to the basal membrane and released their viral content in the extracellular medium, which required their association with CD18 and the actin cytoskeleton. These results highlight that VCC trafficking and virus release are intimately linked to the reorganization of the macrophage actin cytoskeleton in response to external physical cues, suggesting that it might be regulated in tissues by the mechanical stress to which these cells are exposed.

Epistaxis as a marker of the unfavorable course of hypertension

The aim of this research was to study changes in the nasal mucosa vessels in hypertensive patients suffering from recurrent epistaxis. Patients and methods. 78 hypertensive patients aged between 50 and 70, admitted due to epistaxis, were studied. Diabetic, coagulopathic patients and those taking anticoagulants were excluded from the research. All the patients were divided into 2 groups: group 1 (46 people) with a single epistaxis, group 2 (32 people) with a recurrent epistaxis. At the admission, all the patients showed elevated blood pressure, yet the differences between the patients of group 1 and group 2 were not significant. 14 patients of group 2 did not reveal any source of hemorrhage due to a severely deviated septum. These patients underwent septoplasty followed by mucoperichondrium biopsy. Histological study of the samples showed multiple erosions within the epithelial layer, as well as necrotic patches spreading to the deeper mucous coat layers. The microvasculature showed dystrophic changes in the endothelium, its focal desquamation with basal membrane exposure and thrombocytes and erythrocytes adhesion at such places, erythrocyte aggregation, plasma separation, erythrocyte and fibrinous thrombi formation. Thus, the cause of epistaxis is not high blood pressure, but those changes in the nasal mucosa vessels promoted by long-term arterial hypertension.

MORPHOGENESIS OF THE WALL OF GLANDULAR PART OF THE STOMACH IN CHICKENS DURING POSTNATAL PERIOD OF ONTOGENESIS

Knowledge about the morphological features of the structure and functions of the digestive organs provide the basis for rational and effective use of feed, prevention and treatment of gastrointestinal diseases in poultry. In this regard, the study of the morphogenesis of the digestive system in birds and the mechanisms of their regulation is of great importance. The object of the study was the glandular part of the stomach (proventriculus) in chickens of Shaver 579 strain. The material for macro- and microscopic examinations was selected from birds at age of 1, 30, 60, 90, 120, 150, 180, 210, 240, 270, and 300 days and 1, 2, and 3 years; it was fixed in a 10% neutral formalin solution and embedded into paraffin according to conventional methods. For submicroscopic examinations, the material was selected from hens of this strain at age of 180 days. The structure of epitheliocytes in the superficial epithelium and secretory cells of the deep glands was studied in ultrathin sections. Digital indicators of research results were statistically processed by a personal computer using Microsoft Excel program. The glandular stomach in chickens is a direct extension of the esophagus and has the form of a thick-walled tube, the wall of which is formed by mucous, muscular, and serous membranes. The superficial epithelium of the mucosa is represented by cylindrical epithelial cells that are located within the basal membrane. They are linked to each other by different types of contacts and have a well-defined polar differentiation. The lobules of the deep glands are formed by cells with well-developed synthesizing organelles and secretory granules. The morphogenesis of the glandular part of the stomach in chickens according to age aspect is manifested by changes in morphometric parameters of the thickness and the area of the membranes of its wall. The wall thickness increases (between the folds 4223.23 ± 189.25 and in the area of the folds 5561.32 ± 45.01 μm) unevenly in chickens up to age of 240 days. The most developed membrane of the wall of the glandular stomach is the mucosa. Its area increases (by 82.14 ± 0.56%) in chickens up to age of 180 days, and area of muscular and serous membranes decreases (by 15.54 ± 0.65 and 2.32 ± 0.33%, respectively). In older birds, the thickness of the wall and the area of the membranes of the glandular stomach do not change significantly.

The role, carrier and mission of neural crest cells in the skin

The neuro crest arising from the ectoderm is a transient structure and disappears as the neurocrest cells leave these places to invade the whole embryo. The epidermis develops from the ectoderm in the fourth embryonal weeks. The embryos consist of cranial-,vagal-, truncal and sacral segments and the neuro crest cells migrate from these places to form various structures, including the peripheral nerve system, the craniofacial bones and cartilages, etc. The neuro crest cells degrade the basal membrane of neural tube and thereafter migrate through the extracellular matrix in ventromedial and dorsolateral direction. Neural crest cells use various cell adhesion molecules and diferent proteaes. The invasive capacity of these cells is infuenced by aquaporin-1 , too. . The sensory nerves developig from the neuro- crest cells can be found in the epidermis and its appendicular organ, the dermal autonomic nerves in the dermis. The epidermal melanocytes develop partly from the neural crest cells, partly from the Schwann cells of the sensory nerves. The cutaneous nerves produce and secrete neuropeptides thus contributing to the development of the skin into a neuroimmuno-endocrin organ.

Airway Basal Cells, Protectors of Epithelial Walls in Health and Respiratory Diseases

The airway epithelium provides a critical barrier to the outside environment. When its integrity is impaired, epithelial cells and residing immune cells collaborate to exclude pathogens and to heal tissue damage. Healing is achieved through tissue-specific stem cells: the airway basal cells. Positioned near the basal membrane, airway basal cells sense and respond to changes in tissue health by initiating a pro-inflammatory response and tissue repair via complex crosstalks with nearby fibroblasts and specialized immune cells. In addition, basal cells have the capacity to learn from previous encounters with the environment. Inflammation can indeed imprint a certain memory on basal cells by epigenetic changes so that sensitized tissues may respond differently to future assaults and the epithelium becomes better equipped to respond faster and more robustly to barrier defects. This memory can, however, be lost in diseased states. In this review, we discuss airway basal cells in respiratory diseases, the communication network between airway basal cells and tissue-resident and/or recruited immune cells, and how basal cell adaptation to environmental triggers occurs.

Morphological and Ultrastructural Studies of Pecten in the Eurasian Tree Sparrow

We studied the fine histological structures of pecten oculi of the Eurasian tree sparrow using various microscopy techniques. The pecten of the tree sparrow was found to be of a pleated type comprising of pleats, bridges, and base. The light microscopic study revealed further that the pleats consist of capillaries of varying sizes, blood vessels, and numerous pigmented cells that give them a black color. Histochemical studies of pecten showed a large deposition of lipid droplets, which were more abundant in the basal area. The transmission electron microscopy displayed capillaries and blood vessels that remain surrounded by a thick fibrous basal membrane. They are formed of endothelial cells having a large lumen and abluminal area with microfolds. Interstitial spaces were found filled with rounded melanocytes, electron-dense pigment granules, and mitochondria. Observations under the scanning electron microscope revealed the presence of a dense vascular network of capillaries and vessels. In addition, large hyalocytes were also observed on the surface of the pleats. The above observations suggest that the histological structure of the pecten of the tree sparrow resembles those present in the pecten of other diurnal birds. However, further investigation is required to ascertain its functional role in birds.

158 The Identification of Pig Calcium-sensing Receptor (pCaSR) Expression in Porcine Intestinal Enterocytes

Enterocytes play important roles in nutrient absorption, while the intestinal porcine enterocyte cell line (IPEC-J2) is a non-transformed and permanent commercial cell line. The calcium-sensing receptor (CaSR) has been identified as calcium ions and L-amino acids sensor in the gut and studies have demonstrated that the CaSR is involved in nutrient digestion and absorption, as well as gut barrier function. Although the expression of CaSR on the basal membrane of the villus has been found in other animal species, its expression in porcine enterocytes (pCaSR) has not been investigated to date. To investigate the expression of pCaSR in isolated porcine enterocytes and IPEC-J2, cell sorting of ileal enterocytes by fluorescence-activated cell sorting (FACS) based on sucrase-isomaltose as enterocytes marker were performed to obtain pure porcine enterocytes. The digital droplet PCR (ddPCR), immunofluorescence staining, and Western blotting were applied for the detection of pCaSR expression at the gene and protein levels, respectively. Our results showed that about 3.3% of upper epithelial cells were characterized and sorted as pure porcine enterocytes, while the other cells were negative to the enterocytes marker. In addition, neither the isolated porcine enterocytes nor the IPEC-J2 expressed the pCaSR. In summary, pure porcine enterocytes could be obtained by using FACS with the sucrase-isomaltase as enterocytes marker but pCaSR is not expressed in either isolated porcine enterocytes or IPEC-J2, which provides new insights for future work exploring the role of pCaSR in the intestine.

Five hundred million years to mobility: directed locomotion and its ecological function in a turtle barnacle

Movement is a fundamental characteristic of life, yet some invertebrate taxa, such as barnacles, permanently affix to a substratum as adults. Adult barnacles became ‘sessile’ over 500 Ma; however, we confirm that the epizoic sea turtle barnacle, Chelonibia testudinaria , has evolved the capacity for self-directed locomotion as adults. We also assess how these movements are affected by water currents and the distance between conspecifics. Finally, we microscopically examine the barnacle cement. Chelonibia testudinaria moved distances up to 78.6 mm yr −1 on loggerhead and green sea turtle hosts. Movements on live hosts and on acrylic panels occasionally involved abrupt course alterations of up to 90°. Our findings showed that barnacles tended to move directly against water flow and independent of nearby conspecifics. This suggests that these movements are not passively driven by external forces and instead are behaviourally directed. In addition, it indicates that these movements function primarily to facilitate feeding, not reproduction. While the mechanism enabling movement remained elusive, we observed that trails of cement bore signs of multi-layered, episodic secretion. We speculate that proximal causes of movement involve one or a combination of rapid shell growth, cement secretion coordinated with basal membrane lifting, and directed contraction of basal perimeter muscles.

Stationed or Relocating: The Seesawing EMT/MET Determinants from Embryonic Development to Cancer Metastasis

Epithelial and mesenchymal transition mechanisms continue to occur during the cell cycle and throughout human development from the embryo stage to death. In embryo development, epithelial-mesenchymal transition (EMT) can be divided into three essential steps. First, endoderm, mesoderm, and neural crest cells form, then the cells are subdivided, and finally, cardiac valve formation occurs. After the embryonic period, the human body will be subjected to ongoing mechanical stress or injury. The formation of a wound requires EMT to recruit fibroblasts to generate granulation tissues, repair the wound and re-create an intact skin barrier. However, once cells transform into a malignant tumor, the tumor cells acquire the characteristic of immortality. Local cell growth with no growth inhibition creates a solid tumor. If the tumor cannot obtain enough nutrition in situ, the tumor cells will undergo EMT and invade the basal membrane of nearby blood vessels. The tumor cells are transported through the bloodstream to secondary sites and then begin to form colonies and undergo reverse EMT, the so-called “mesenchymal-epithelial transition (MET).” This dynamic change involves cell morphology, environmental conditions, and external stimuli. Therefore, in this manuscript, the similarities and differences between EMT and MET will be dissected from embryonic development to the stage of cancer metastasis.

A rare case of coexistence of Wegener’s granulomatosis and pulmonary tuberculosis with subsequent development of thrombosis of the cerebral veins

Background Granulomatosis with polyangiitis (GPA), also known as Wegener’s granulomatosis, is an idiopathic systemic disease typically affecting the lungs, although other organs may also be involved. Case presentation A 28-year-old male was admitted to Baqiyatallah university hospital in Teheran (Iran) after a 3-week history of fever and productive cough. The patient gradually developed fatigue, arthralgia, hematuria, nausea, vomiting, dyspnea, hemoptysis, weight loss, oliguria and then anuria. Chest-X-ray (CXR) and computerized tomography scan revealed cavitating nodular opacities in the right lung lobe. Furthermore, plasma creatinine increased from 2.2 to 4 mg/dl in a few days. Histopathological examination of kidney biopsy revealed peri-glomerular and peri-vascular inflammation, degeneration and necrosis of the tubular epithelial lining, red blood cell casts, distorted glomerular structure, fibrin thrombi, segmental breaks of the glomerular basal membrane, disruption of Bowman's capsular membrane and crescent formation of the affected glomeruli. An abnormal CXR, an abnormal urinary sediment and a typical kidney histology were used as criteria to diagnose glomerulonefritis with poliangiitis (GPA). Bronchoalveolar lavage smear and PCR turned out positive for mycobacterium tuberculosis. After 3 months of treatment for (GPA) and tuberculosis the patient developed headache and seizure. Cerebral Magnetic Resonance Venography revealed cerebral venous thrombosis of the sinus transverse and sigmoid. Conclusions Tuberculosis may coexist with GPA, as it occurred in our patient. Since a crescentic glomerulonephritis can progress to renal failure, clinicians should always be aware of potential multiple conditions when considering differential diagnoses.