Reelin through the years: From brain development to inflammation

Reelin was originally identified as a regulator of neuronal migration and synaptic function, but its non-neuronal functions have received far less attention. Reelin participates in organ development and physiological functions in various tissues, but it is also dysregulated in some diseases. In the cardiovascular system, Reelin is abundant in the blood, where it contributes to platelet adhesion and coagulation, as well as vascular adhesion and permeability of leukocytes. It is a pro-inflammatory and pro-thrombotic factor with important implications for autoinflammatory and autoimmune diseases such as multiple sclerosis, Alzheimer's disease, arthritis, atherosclerosis, or cancer. Mechanistically, Reelin is a large secreted glycoprotein that binds to several membrane receptors, including ApoER2, VLDLR, integrins, and ephrins. Reelin signaling depends on the cell type but mostly involves phosphorylation of NF-κB, PI3K, AKT, or JAK/STAT. This review focuses on non-neuronal functions and the therapeutic potential of Reelin, while highlighting secretion, signaling, and functional similarities between cell types.

Research Progress on Intracranial Lymphatic Circulation and Its Involvement in Disorders

The lymphatic system is an important part of the circulatory system, as an auxiliary system of the vein, which has the functions of immune defense, maintaining the stability of the internal environment, and regulating the pressure of the tissue. It has long been thought that there are no typical lymphatic vessels consisting of endothelial cells in the central nervous system (CNS). In recent years, studies have confirmed the presence of lymphatic vessels lined with endothelial cells in the meninges. The periventricular meninges of the CNS host different populations of immune cells that affect the immune response associated with the CNS, and the continuous drainage of interstitial and cerebrospinal fluid produced in the CNS also proceeds mainly by the lymphatic system. This fluid process mobilizes to a large extent the transfer of antigens produced by the CNS to the meningeal immune cells and subsequently to the peripheral immune system through the lymphatic network, with clinically important implications for infectious diseases, autoimmunity, and tumor immunology. In our review, we discussed recent research advances in intracranial lymphatic circulation and the pathogenesis of its associated diseases, especially the discovery of meningeal lymphatic vessels, which has led to new therapeutic targets for the treatment of diseases associated with the intracranial lymphatic system.

Spatial Organization of the Transport of Interstitial Fluid and Lymph in Rat Liver (Scanning Electron Microscopy of Injection Replicas)

Using the method of scanning electron microscopy of injection replicas, we studied the movement of a new injection mass between the blood microcirculation system, interstitial space, lymphatic system, and bile transport system in rat liver under normal conditions and 3 days after the occlusion of the common bile duct. The casts of the perisinusoidal spaces of Disse's after injection of the injection mass through the portal vein and common bile duct were obtained. Their direct transition not only in "leakages" structurally related to lymphatic capillaries in interlobular spaces, but also in perivascular spaces around the portal and hepatic veins. The flow of the injection mass through the perivascular spaces leads to the formation of peculiar "sheaths" around hepatic veins and components of the portal complex. The proposed approach allows effective visualization of the structural basis of interaction of various compartments of the fluid microcirculation in the liver under normal and pathological conditions.

The Role of Interstitial Matrix and the Lymphatic System in Gastrointestinal Lipid and Lipoprotein Metabolism

This review emphasizes the events that take place after the chylomicrons are secreted by the enterocytes through exocytosis. First, we will discuss the journey of how chylomicrons cross the basement membrane to enter the lamina propria. Then the chylomicrons have to travel across the lamina propria before they can enter the lacteals. To understand the factors affecting the trafficking of chylomicron particles across the lamina propria, it is important to understand the composition and properties of the lamina propria. With different degree of hydration, the pores of the lamina propria (sponge) changes. The greater the hydration, the greater the pore size and thus the easier the diffusion of the chylomicron particles across the lamina propria to enter the lacteals. The mechanism of the entry of lacteals is discussed in considerable details. We and others have demonstrated that intestinal fat absorption, but not the absorption of protein or carbohydrates, activates the intestinal mucosal mast cells to release many products including mucosal mast cell protease II in the rat. The activation of intestinal mucosal mast cells by fat absorption involves the process of chylomicron formation since the absorption of both medium and short-chain fatty acids do not activate the mast cells. Fat absorption has been associated with increased intestinal permeability. We hypothesize that there is a link between fat absorption, activation of mucosal mast cells, and the leaky gut phenomenon (increased intestinal permeability). Microbiome may also be involved in this chain of events associated with fat absorption. This review is presented in sequence under the following headings: (1) Introduction; (2) Structure and properties of the gut epithelial basement membrane; (3) Composition and physical properties of the interstitial matrix of the lamina propria; (4) The movement of chylomicrons across the interstitial matrix of the lamina propria and importance of the hydration of the interstitial matrix of the lamina propria and the movement of chylomicrons; (5) Entry of the chylomicrons into the intestinal lacteals; (6) Activation of mucosal mast cells by fat absorption and the metabolic consequences; and (7) Link between chylomicron transport, mucosal mast cell activation, leaky gut, and the microbiome.

Lymphatic Circulation Disseminates Bartonella Infection Into Bloodstream

The hallmark of Bartonella infection is long-lasting intraerythrocytic parasitism. However, the process of Bartonella bacteremia is still enigmatic. In the current study, we used Bartonella tribocorum to determine how Bartonella invasion into the bloodstream from dermal inoculation might occur. Bartonella was poorly phagocytized by peritoneal macrophages in vitro. Intracellular Bartonella survived and replicated in macrophages at an early stage of infection. Intracellular Bartonella inhibited spontaneous cell death of macrophages. They also inhibited Salmonella-induced pyroptosis and mildly reduced inflammasome activation through an unidentified mechanism. A rat model confirmed that Bartonella was also inadequately phagocytized in vivo, because numerous free-floating bacilli were observed in lymph collected from thoracic duct drainage as early as 2 hours after inoculation. Lymphatic fluid drainage in the bloodstream significantly reduced the bacterial load in the bloodstream. These findings illustrated a potential route by which Bartonella invade bloodstream from dermal inoculation before they are competent to infect erythrocytes.

Surrogacy in antiviral drug development

The coming of age of molecular biology has resulted in an explosion in our understanding of the pathogenesis of virus related diseases. New pathogens have been identified and characterized as being responsible for old diseases. Empirical clinical evaluation of morbidity and mortality as outcome measures after a therapeutic intervention have started to give way to the use of an increasing number of surrogate markers. Using a combination of these markers, it is now possible to measure and monitor the pathogen as well as the host's response. Nowhere is this better exemplified in virology than in the field of AIDS. We have utilized the advances in pathogenesis and new antiretroviral drug development to: * develop a new class of drugs which block the entry of HIV-1 into cells. * develop a new approach for effectively delivering these drugs to those tissues in which most viral replication takes place. Over the last 10 years, our work has progressed from concept to clinical trial. Our laboratory based evaluation of the new molecules developed as well as our clinical evaluation of their safety and efficacy have had to respond and adapt to the rapid changes taking place in AIDS research. This paper discusses the problems encountered and the lessons learnt.