Fucoidan from Fucus vesiculosus Inhibits Inflammatory Response, Both In Vitro and In Vivo.

Fucoidan has been reported to present diverse bioactivities, but each extract has specific features from which a particular biological activity, such as immunomodulation, must be confirmed. In this study a commercially available pharmaceutical-grade fucoidan extracted from Fucus vesiculosus, FE, was characterized and its anti-inflammatory potential was investigated. Fucose was the main monosaccharide (90 mol%) present in the studied FE, followed by uronic acids, galactose, and xylose that were present at similar values (3.8-2.4 mol%). FE showed a molecular weight of 70 kDa and a sulfate content of around 10%. The expression of cytokines by mouse bone-marrow-derived macrophages (BMDMs) revealed that the addition of FE upregulated the expression of CD206 and IL-10 by about 28 and 22 fold, respectively, in respect to control. This was corroborated in a stimulated pro-inflammatory situation, with the higher expression (60 fold) of iNOS being almost completely reversed by the addition of FE. FE was also capable of reverse LPS-caused inflammation in an in vivo mouse model, including by reducing macrophage activation by LPS from 41% of positive CD11C to 9% upon fucoidan injection. Taken together, the potential of FE as an anti-inflammatory agent was validated, both in vitro and in vivo.

Stabilization of Natural Pigments in Ethanolic Solutions for Food Applications: The Case Study of Chlorella vulgaris.

Chlorella vulgaris is a green microalga with a high chlorophyll content, representing a valuable source of green pigments for food applications. As the application of whole biomass can promote an unpleasant fish-like flavor, the use of chlorophyll extract can overcome this drawback. However, chlorophylls tend to easily degrade when out of the chloroplasts, decreasing their potential as a food ingredient. Thus, to study the suitable conditions for isolated chlorophylls preservation, in this work, the influence of temperature (4 to 60 °C), light (dark or 24 h photoperiod), alkaline conditions (with or without aqueous NaOH addition), and modified atmosphere (air or argon atmosphere) on the stability of the color in ethanolic solutions obtained from C. vulgaris were studied. The loss of green color with temperature followed the first-order kinetics, with an activation energy of 74 kJ/mol. Below 28 °C and dark conditions were suitable to preserve isolated chlorophylls. The addition of NaOH and an inert argon-rich atmosphere did not exhibit a statistically positive effect on color preservation. In the case study, cooked cold rice was colored to be used in sushi. The color remained stable for up to 3 days at 4 °C. Therefore, this work showed that C. vulgaris chlorophylls could be preserved in ethanolic solutions at room or lower temperatures when protected from light, allowing them to obtain a suitable natural food ingredient to color foodstuffs.

PIKfyve activity is required for lysosomal trafficking of tau aggregates and tau seeding.

Tauopathies, such as Alzheimer's disease (AD), are neurodegenerative disorders characterized by the deposition of hyperphosphorylated tau aggregates. Proteopathic tau seeds spread through the brain in a temporospatial pattern, indicative of transsynaptic propagation. It is hypothesized that reducing the uptake of tau seeds and subsequent induction of tau aggregation could be a potential approach for abrogating disease progression in AD. Here, we studied to what extent different endosomal routes play a role in the neuronal uptake of preformed tau seeds. Using pharmacological and genetic tools, we identified dynamin-1, actin, and Rac1 as key players. Furthermore, inhibition of PIKfyve, a protein downstream of Rac1, reduced both the trafficking of tau seeds into lysosomes and the induction of tau aggregation. Our work shows that tau aggregates are internalized by a specific endocytic mechanism and that their fate once internalized can be pharmacologically modulated to reduce tau seeding in neurons.

Liposomal Formulations of a New Zinc(II) Complex Exhibiting High Therapeutic Potential in a Murine Colon Cancer Model.

Colorectal cancer is the second leading cause of cancer-related mortality. Many current therapies rely on chemotherapeutic agents with poor specificity for tumor cells. The clinical success of cisplatin has prompted the research and design of a huge number of metal-based complexes as potential chemotherapeutic agents. In this study, two zinc(II) complexes, [ZnL2] and [ZnL(AcO)], where AcO is acetate and L is an organic compound combining 8-hydroxyquinoline and a benzothiazole moiety, were developed and characterized. Analytical and spectroscopic studies, namely, NMR, FTIR, and UV-Vis allowed us to establish the complexes' structures, demonstrating the ligand-binding versatility: tetradentate in [ZnL(AcO)] and bidentate in [ZnL2]. Complexes were screened in vitro using murine and human colon cancer cells cultured in 2D and 3D settings. In 2D cells, the IC50 values were <22 µM, while in 3D settings, much higher concentrations were required. [ZnL(AcO)] displayed more suitable antiproliferative properties than [ZnL2] and was chosen for further studies. Moreover, based on the weak selectivity of the zinc-based complex towards cancer cell lines in comparison to the non-tumorigenic cell line, its incorporation in long-blood-circulating liposomes was performed, aiming to improve its targetability. The resultant optimized liposomal nanoformulation presented an I.E. of 76% with a mean size under 130 nm and a neutral surface charge and released the metal complex in a pH-dependent manner. The antiproliferative properties of [ZnL(AcO)] were maintained after liposomal incorporation. Preliminary safety assays were carried out through hemolytic activity that never surpassed 2% for the free and liposomal forms of [ZnL(AcO)]. Finally, in a syngeneic murine colon cancer mouse model, while free [ZnL(AcO)] was not able to impair tumor progression, the respective liposomal nanoformulation was able to reduce the relative tumor volume in the same manner as the positive control 5-fluorouracil but, most importantly, using a dosage that was 3-fold lower. Overall, our results show that liposomes were able to solve the solubility issues of the new metal-based complex and target it to tumor sites.

Synthesis of 3-O-Sulfated Disaccharide and Tetrasaccharide Standards for Compositional Analysis of Heparan Sulfate.

3-O-Sulfation on the glucosamine sugar unit in heparan sulfate (HS) is linked to various biological functions, including the anticoagulant activity to treat thrombotic disorders in hospitals. The 3-O-sulfated glucosamine is biosynthesized by heparan sulfate glucosamine 3-sulfotransferases. Because of its biological significance, there is a need for 3-O-sulfated oligosaccharide standards to facilitate the compositional analysis of HS. These oligosaccharides must contain a Δ4,5-unsaturated uronic acid (ΔUA) residue at the nonreducing end, which is due to the depolymerization reaction catalyzed by heparin lyases used during the compositional analysis procedure. Here, we describe a protocol for the preparation of one 3-O-sulfated disaccharide (compound 4) and three 3-O-sulfated tetrasaccharides (compound 1-3) in a milligram scale. The synthesis of 3-O-sulfated disaccharide and tetrasaccharide standards was completed by degrading synthetic octasaccharides using heparin lyases. Further analysis revealed that 3-O-sulfated oligosaccharide standards are labile under basic conditions, confirming the findings from a previous study. The unwanted degradation was reduced by decreasing the pH in the presence of phosphate buffer. The 3-O-sulfated oligosaccharide standards are reagents to characterize 3-O-sulfation in HS derived from biological sources.

Production and characterization of a novel Delta-like 1 functional unit as a tool for Notch pathway activation and generation of a specific antibody.

Notch signalling is an evolutionary conserved cell-to-cell communication pathway crucial for development and tissue homeostasis. Abnormal Notch signalling by mutations or deregulated expression of its receptors and/or ligands can lead to cancer making it a potential therapeutic target. Delta-like1 (DLL1) is a ligand of the Notch pathway implicated in different types of cancer, including breast cancer. Herein, we produced rhDLL1-DE3, a novel soluble form of DLL1 protein, which contains the DSL domain and EGF1-3 repeats critical for Notch pathway activation. cDNA fragments of human DLL1, encoding truncated versions of DLL1 with regions required to activate Notch receptors, were cloned and expressed as histidine-fused proteins in bacterial and mammalian cells. Expression tests in mammalian cells showed almost exclusively expression of the rhDLL1-DE3 protein form comprising the minimal binding regions DSL to EGF3 to Notch receptors. The highest yield of rhDLL1-DE3 was obtained from E. coli inclusion bodies. The produced protein, with purity higher than 95% bound to human Notch1 recombinant protein, by both Biolayer interferometry and ELISA assays. Cellular assays revealed rhDLL1-DE3 was biologically active as it increased expression of Notch-dependent genes in inducible pluripotent and breast cancer cells. Moreover, rhDLL1-DE3 allowed the generation of polyclonal antibodies by immunization that efficiently recognized DLL1 proteins by immunoblot, and caused a significant decrease of Notch1 expression in MCF7 breast cancer cells. The rhDLL1-DE3 protein might thus be used for Notch pathway activation and to generate anti-DLL1 monoclonal antibodies by immunization or phage display technology to unveil the effect of DLL1 in breast cancer.

Ions release Evaluation and Changes in Mini-implant Orthodontic Surface.

AIM: To evaluate, in vitro, the mini-implant surface changes and the release of ions after immersion in artificial saliva during follow-up of 60 and 120 days. MATERIALS AND METHODS: As for the surface features, examined in a scanning electron microscope (SEM), before and after immersion in artificial saliva, there was a rough and uneven surface, suggestive of corrosion areas for the two trademarks evaluated after 120 days of immersion. The extracts generated in artificial saliva analysis were submitted to energy dispersive spectroscopy to identify the solid corrosion products produced on the surfaces of miniscrews. RESULTS: Both SIN miniscrews and Neodent brands were observed to release minimal quantities of silver ions, chromium, iron, nickel, titanium, and vanadium. Regarding titanium, this index varied from 88.84% in the control group of Neodent brand, and 91.29% in the control group of SIN brand. For the aluminum content, the quantities ranged from 4.91% in group immersed for 60 days in Neodent brand to 8.71% for the SIN control group. Considering vanadium, the index ranged from 2.65% in the group immersed for 120 days to 4.53% in the control group, both for Neodent brand. Statistically significant differences in iron ion were observed between the control group and the miniscrews brand SIN after 60 and 120 days and for Neodent after 60 days of immersion. The titanium ions suffered statistically significant decrease for both brands after 120 days of storage when compared with the control group. CONCLUSION: The studied miniscrews showed results consistent with the biosafety of alloys for use, in vivo. CLINICAL SIGNIFICANCE: The knowledge of the physical/chemical state of corrosion products released in the oral cavity is very important for the toxicological assessment of metal alloys used in dental miniscrews.

[Pneumothorax Secondary to Pulmonary Tuberculosis]. / Pneumotórax Secundário a Tuberculose Pulmonar.

The typical clinical presentation of pulmonary tuberculosis is defined by a long-term respiratory and constitutional semiology. However, the overlapping of acute symptomatology may occur, with secondary pneumothorax being a rare but documented presentation. The authors present the case of a 58-year-old male patient who presented at the emergency room with a one day history of thoracalgia on the left hemithorax. He also reported weight loss, night sweats and fatigue for a few months. The physical examination revealed left decreased breath sounds. Chest X-ray showed left pneumothorax, with bilateral pleuroparenchymal reinforcement and computerized tomography scan showed left pneumothorax, conditioning atelectasis of the pulmonary parenchyma and bilateral apical cavity images. Thoracic drainage was placed in the 5th left intercostal space of the anterior axillary line. Microbiological examination of sputum revealed the presence of mycobacterium tuberculosis complex. He was hospitalized under tuberculostatic medication, and presented good evolution.

A apresentação clínica característica da tuberculose pulmonar define-se por um quadro respiratório e constitucional de longa duração. Contudo, a sobreposição de sintomatologia aguda pode ocorrer, sendo o pneumotórax secundário uma possível apresentação que apesar de rara se encontra documentada. Os autores apresentam o caso de um homem de 58 anos que recorreu ao Serviço de Urgência por toracalgia esquerda. Referia também perda ponderal, sudorese nocturna e astenia desde há alguns meses. Apresentava-se emagrecido, com diminuição do murmúrio vesicular esquerdo. A radiografia revelou pneumotórax esquerdo, com reforço pleuroparenquimatoso bilateral. Realizou tomografia computadorizada que mostrou pneumotórax à esquerda condicionando atelectasia do parênquima pulmonar e imagens cavitadas apicais bilateralmente. Foi colocado dreno torácico no 5o espaço intercostal esquerdo da linha axilar anterior. O exame microbiológico da expectoração revelou presença de mycobacterium tuberculosis complex, tendo sido internado sob tuberculostáticos, e apresentado boa evolução.

Evaluation of cervico-occlusal dimensions of maxillary and mandibular incisor brackets for lingual orthodontics.

AIM: The purpose of this study was to analyze the cervico-occlusal dimensions of brackets used in lingual orthodontics for maxillary and mandibular central and lateral incisors, to compare them with the numbers informed by the manufacturer. MATERIALS AND METHODS: The brackets were placed in a template and analyzed by scanning electron microscopy (SEM), evaluating the images with the aid of a software that allowed determination of reference points, tracing of lines on the bracket images and measurement of the distances. RESULTS: Brackets manufactured by Dm Ceosa Hiro, Tecnident PSWb and Dentaurum Magic did not present statistically significant differences between the mean values of slot heights and the values informed by manufacturers. Conversely, the brands Ormco 7th generation, Ormco STb, GAC Innovation L, ORJ-ORG, Tecnident, Ormco STb LSW and Adenta evolution STL exhibited statistically significant differences. CONCLUSION: In general, there was a deficiency in the standar-dization of cervico-occlusal measurements of slots of the brackets analyzed. CLINICAL SIGNIFICANCE: Manufacturers should be attentive to the quality control of their materials. Future studies will analyze the actual clinical influence of these findings on the orthodontic mechanics.

Membrane trafficking alterations in breast cancer progression.

Breast cancer (BC) is the most common type of cancer in women, and remains one of the major causes of death in women worldwide. It is now well established that alterations in membrane trafficking are implicated in BC progression. Indeed, membrane trafficking pathways regulate BC cell proliferation, migration, invasion, and metastasis. The 22 members of the ADP-ribosylation factor (ARF) and the >60 members of the rat sarcoma (RAS)-related in brain (RAB) families of small GTP-binding proteins (GTPases), which belong to the RAS superfamily, are master regulators of membrane trafficking pathways. ARF-like (ARL) subfamily members are involved in various processes, including vesicle budding and cargo selection. Moreover, ARFs regulate cytoskeleton organization and signal transduction. RABs are key regulators of all steps of membrane trafficking. Interestingly, the activity and/or expression of some of these proteins is found dysregulated in BC. Here, we review how the processes regulated by ARFs and RABs are subverted in BC, including secretion/exocytosis, endocytosis/recycling, autophagy/lysosome trafficking, cytoskeleton dynamics, integrin-mediated signaling, among others. Thus, we provide a comprehensive overview of the roles played by ARF and RAB family members, as well as their regulators in BC progression, aiming to lay the foundation for future research in this field. This research should focus on further dissecting the molecular mechanisms regulated by ARFs and RABs that are subverted in BC, and exploring their use as therapeutic targets or prognostic markers.

Metastatic Myoepithelial Carcinoma Ex Pleomorphic Adenoma of the Sublingual Salivary Gland.

Myoepithelial carcinoma ex pleomorphic adenoma is a very rare malignant neoplasm of the salivary gland. Owing to its rarity, its clinical features and treatment are not well characterized. We describe a case of a patient who was referred to our department with a six-month history of a bulge on the right side of the floor of the mouth and a submandibular mass with progressive enlargement. The mass was resected, and an elective level I neck dissection was performed. Histological examination revealed myoepithelial carcinoma ex pleomorphic adenoma of the sublingual salivary gland. Thoracic computed tomography and biopsy revealed lung metastases. The patient died two years after the diagnosis.

Mesenteric Schwannoma, Intestinal Malrotation and Ileal Diverticulum: A Unique Association.

Mesenteric schwannomas are rare benign tumors that arise in the mesentery. Ileal diverticula and intestinal malrotation in adults are rare findings, since they are usually asymptomatic. We present the case of an 86-year-old man, without any known previously known medical conditions, who was admitted in the emergency department with recurrent abdominal distension and intense pain. The radiological study suggested an intestinal malrotation. An exploratory laparotomy confirmed the intestinal malrotation with intermesenteric bands, as well as a mesenteric mass adjacent to an ileal diverticulum. Following a segmental enterectomy, the histology of the mass reported a mesenteric schwannoma. To the best of our knowledge, this is the first report of such association. We therefore present this report to showcase the diagnostic and therapeutical challenges in managing these conditions.

Os schwanomas mesentéricos são tumores benignos raros com origem nas células de Schwann do mesentério. Divertículos ileais e má-rotação intestinal em adultos são também achados raros, por serem geralmente assintomáticos. Neste artigo apresentamos o caso de um homem de 86 anos, sem antecedentes conhecidos, que recorre à urgência por um quadro de dor abdominal e distensão. O estudo imagiológico sugeria uma má rotação intestinal, pelo que se realizou uma laparotomia exploradora, onde se verificaram várias bandas intermesentéricas, bem como uma massa mesentérica adjacente a um divertículo ileal. Foi realizada lise de bandas e uma enterectomia segmentar. A avaliação anatomo-patológica mostrou tratar-se de um schwanoma mesentérico. Tanto quanto é do nosso conhecimento, este é o primeiro relato de um caso com esta associação tripla, e tem como objetivo reforçar os desafios diagnósticos e terapêuticos na abordagem destas patologias.

Ewing's Sarcoma of the Zygoma: A Very Rare Location.

Ewing's sarcoma is a rare and aggressive neoplasm that typically affects the long bones. The presence of a primary tumor in the facial bones is extremely uncommon. Here, we present a case of a 21-year-old male with Ewing's sarcoma of the zygoma. To date, only a few such cases have been reported worldwide in the literature.

Clinical Worsening of Charcot-Marie-Tooth Disease Due to Overlapping Acute Inflammatory Polyneuropathy.

We report a case of a six-year-old male with Charcot-Marie-Tooth disease (CMT) type 1B due to MPZ gene mutation who experienced an acute worsening of his symptoms a few years after the diagnosis. He was not able to walk without assistance and had transitory paresthesia in his hands, 10 days after suffering from an upper respiratory and diarrheal illness. The investigation revealed elevated cerebrospinal fluid (CSF) protein levels with no pleocytosis, and sensory and motor chronic demyelinating neuropathy without active denervation findings on electrophysiological studies. The patient completely recovered following treatment with intravenous immunoglobulin. We describe the patient's history and engage in a review of the literature to find similar clinical cases. It has been proposed that MPZ gene mutations can change the myelin structure and result in abnormal exposure of the nervous cell components to immune cells. Hence, patients with this type of CMT would be predisposed to concurrent inflammatory forms of neuropathy.

Protein interactors of 3-O sulfated heparan sulfates in human MCI and age-matched control cerebrospinal fluid.

Heparan sulfates (HS) proteoglycans are commonly found on the cell surface and mediate many processes. Binding of HS ligands is determined by the sulfation code on the HS chain that can be N-/2-O/6-O- or 3-O-sulfated, generating heterogenous sulfation patterns. 3-O sulfated HS (3S-HS) play a role in several (patho)physiological processes such as blood coagulation, viral pathogenesis and binding and internalization of tau in Alzheimer's disease. However, few 3S-HS-specific interactors are known. Thus, our insight into the role of 3S-HS in health and disease is limited, especially in the central nervous system. Using human CSF, we determined the interactome of synthetic HS with defined sulfation patterns. Our affinity-enrichment mass spectrometry studies expand the repertoire of proteins that may interact with (3S-)HS. Validating our approach, ATIII, a known 3S-HS interactor, was found to require GlcA-GlcNS6S3S for binding, similar to what has been reported. Our dataset holds novel, potential HS and 3S-HS protein ligands, that can be explored in future studies focusing on molecular mechanisms that depend on 3S-HS in (patho)physiological conditions.

Small Bowel Obstruction by a Phytobezoar in a Patient With Previous Antrectomy and Billroth II Reconstruction.

A phytobezoar is a conglomerate of improperly digested fruit and vegetable debris, and its development is associated, amongst other factors, with previous gastric surgery. Most phytobezoars remain asymptomatic and are incidentally found during imaging or interventional procedures. However, in some patients, they can cause small bowel obstruction, which can subsequently lead to severe complications. Although the clinical findings are similar to other causes of intestinal obstruction, there are some particular diagnostic and treatment features more specific to phytobezoars. We present a case of an 85-year-old man with a history of previous antrectomy and Billroth II reconstruction who came to the emergency department with bilateral aspiration pneumonia and intestinal obstruction due to a bezoar. The CT scan showed bilateral inferior lobe pulmonary consolidation, as well as a marked dilation of the small bowel with gas-fluid levels and a transition to normal caliber in the terminal ileum, where an oval mottled-appearing mass suggesting a bezoar was present. An urgent laparotomy confirmed the diagnosis, and an enterotomy with removal of the bezoar was performed. Phytobezoars must be considered as a cause of intestinal obstruction, particularly when patients have a history of previous gastric surgery. Its radiological findings, particularly in CT scans, are specific and should be appreciated to establish the diagnosis promptly. The treatment of small bowel obstruction due to a phytobezoar requires surgery most of the time, and the surgeon must bear in mind the need to look for the existence of other bezoars in the gastrointestinal tract to prevent reoccurrence.

Home-Based Rehabilitation Following Subtalar Dislocation: A Case Report.

The demand for physical medicine and rehabilitation services has risen significantly. Immediate rehabilitation is not always readily available which may compromise patients' functional recovery. Here, we describe a rare subtalar dislocation case and how an unsupervised home-based rehabilitation program allowed functional recovery. A 49-year-old male presented to the emergency department with an injury to the right ankle which resulted from a 3-meter height fall with his foot in plantar flexion and inversion. Clinical and imaging findings confirmed a diagnosis of a rare case of subtalar dislocation. The post-injury AOFAS Ankle-Hindfoot Scale score was 24/100 points. After six weeks of immobilization, a patient-tailored home-based rehabilitation program was prescribed. Adherence to our home-based rehabilitation program was critical to allow a range-of-motion improvement and functional recovery. Delaying rehabilitation may lead to long-term functional impairments. Thus, acknowledging the post-acute period as critical to initiate rehabilitation is mandatory. When outpatient rehabilitation settings are not readily available due to high demand, comprehensive patient education, and home-based rehabilitation programs may constitute effective alternative interventions. We demonstrate the significant improvement obtained with an early patient-tailored home-based rehabilitation program in range-of-motion and functional outcomes in a case of medial subtalar dislocation.

Pediatric Lisfranc Fracture-Dislocation: A Case Report.

Lisfranc injury is extremely rare in the pediatric population and little evidence exists to guide the treatment at this age. We present a clinical case of a rare Lisfranc fracture-dislocation at pediatric age. An 11-year-old male was admitted to the emergency department, in October 2020, after a motorcycle incident. He was diagnosed with a Lisfranc fracture-dislocation of the right foot: Myerson type B2. Fourteen days after the injury, he underwent surgical treatment with open reduction and internal fixation with 3.5 mm solid fully threaded screws. At 18 months postoperative, the patient was asymptomatic, didn't present any limitations, presented an American Orthopedic Foot and Ankle Score (AOFAS) midfoot score of 93%, and excellent results of the 12-Item Short Form Survey (SF-12) - PCS-12 (Physical Score): 52.52277 and MCS-12 (Mental Score): 62.12820. The foot maintained a good configuration without significant malalignment, however, a screw breakage occurred before the implant removal, and a premature physeal arrest developed on the base of the first metatarsal bone. Clinical and radiographic evaluation of Lisfranc injuries may be challenging in the pediatric population. Regarding the treatment, anatomical alignment is mandatory, and good or excellent outcomes have been achieved with anatomical reduction and internal fixation. We recommend early implant removal to avoid screw breakage and avoid the use of screws in the first metatarsal physis, due to the risk of premature physeal arrest.

The 3-O sulfation of heparan sulfate proteoglycans contributes to the cellular internalization of tau aggregates.

BACKGROUND: Considering the high correlation between the functional decline in Alzheimer's disease (AD) and the propagation of aggregated tau protein, many research efforts are focused on determining the underlying molecular mechanisms of tau spreading. Heparan sulfate proteoglycans (HSPGs) were reported to mediate cellular uptake of tau aggregates. Specifically, the heparan sulfates (HS) sulfation plays a critical role in the interaction of HSPGs with aggregated tau. HS can be N-/2-O/6-O- or 3-O-sulfated, some of which have been reported to take part in the interaction with tau aggregates. However, the role of the 3-O sulfation remains enigmatic. RESULTS: Here, we studied the contribution of HS 3-O sulfation in the binding and cellular uptake of tau aggregates. We observed reduced tau aggregates uptake in absence of 3-O sulfation or when outcompeting available cellular 3-O sulfated HS (3S-HS) with antithrombin III. The lack of HS3ST1-generated HS products in the HS3ST1-/- cells was further corroborated with an LC-MS/MS using 13C-labeled HS calibrants. Here, we showed that these functional changes can be explained by a higher affinity of aggregated tau to 3S-HS. When targeting tau aggregates with 3-O sulfation-containing HS, we observed an increase in inhibition of tau aggregates uptake. CONCLUSIONS: These data indicate that HS 3-O sulfation plays a role in the binding of tau aggregates and, thus, contributes to their cellular uptake, highlighting a potential target value to modulate tau pathogenesis.

RAB3A Regulates Melanin Exocytosis and Transfer Induced by Keratinocyte-Conditioned Medium.

Skin pigmentation is imparted by melanin and is crucial for photoprotection against UVR. Melanin is synthesized and packaged into melanosomes within melanocytes and is then transferred to keratinocytes (KCs). Although the molecular players involved in melanogenesis have been extensively studied, those underlying melanin transfer remain unclear. Previously, our group proposed that coupled exocytosis/phagocytosis is the predominant mechanism of melanin transfer in human skin and showed an essential role for RAB11B and the exocyst tethering complex in this process. In this study, we show that soluble factors present in KC-conditioned medium stimulate melanin exocytosis from melanocytes and transfer to KCs. Moreover, we found that these factors are released by differentiated KCs but not by basal layer KCs. Furthermore, we found that RAB3A regulates melanin exocytosis and transfer stimulated by KC-conditioned medium. Indeed, KC-conditioned medium enhances the recruitment of RAB3A to melanosomes in melanocyte dendrites. Therefore, our results suggest the existence of two distinct routes of melanin exocytosis: a basal route controlled by RAB11B and a RAB3A-dependent route, stimulated by KC-conditioned medium. Thus, this study provides evidence that soluble factors released by differentiated KCs control skin pigmentation by promoting the accumulation of RAB3A-positive melanosomes in melanocyte dendrites and their release and subsequent transfer to KCs.