Lixa C, Mujo A, de Magalhães MTQ, Almeida FCL, Lima LMTR, Pinheiro AS. Oligomeric transition and dynamics of RNA binding by the HuR RRM1 domain in solution. J Biomol NMR. 2018 Dec;72(3-4):179-192.
DOI: 10.1007/s10858-018-0217-y
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Human antigen R (HuR) functions as a major post-transcriptional regulator of gene expression through its RNA-binding activity. HuR is composed by three RNA recognition motifs, namely RRM1, RRM2, and RRM3. The two N-terminal RRM domains are disposed in tandem and contribute mostly to HuR interaction with adenine and uracil-rich elements (ARE) in mRNA. Here, we used a combination of NMR and electrospray ionization–ion mobility spectrometry–mass spectrometry (ESI–IMS–MS) to characterize the structure, dynamics, RNA recognition, and dimerization of HuR RRM1. Our solution structure reveals a canonical RRM fold containing a 19-residue, intrinsically disordered N-terminal extension, which is not involved in RNA binding. NMR titration results confirm the primary RNA-binding site to the two central β-strands, β1 and β3, for a cyclooxygenase 2 (Cox2) ARE I-derived, 7-nucleotide RNA ligand. We show by 15N relaxation that, in addition to the N- and C-termini, the β2–β3 loop undergoes fast backbone dynamics (ps–ns) both in the free and RNA-bound state, indicating that no structural ordering happens upon RNA interaction. ESI–IMS–MS reveals that HuR RRM1 dimerizes, however dimer population represents a minority. Dimerization occurs via the α-helical surface, which is oppositely orientated to the RNA-binding β-sheet. By using a DNA analog of the Cox2 ARE I, we show that DNA binding stabilizes HuR RRM1 monomer and shifts the monomer–dimer equilibrium toward the monomeric species. Altogether, our results deepen the current understanding of the mechanism of RNA recognition employed by HuR.
Nico D, Conde L, Rivera-Correa JL, Vasconcelos-Dos-Santos A, Mesentier-Louro L, Freire-de-Lima L, Arruda MB, Freire-de-Lima CG, Ferreira ODC Jr, Lopes Moreira ME, Zin AA, Vasconcelos ZFM, Otero RM, Palatnik-de-Sousa CB, Tanuri A, Todeschini AR, Savino W, Rodriguez A, Morrot A. Prevalence of IgG Autoantibodies against GD3 Ganglioside in Acute Zika Virus Infection. Front Med (Lausanne). 2018 Mar 9;5:25.
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Zika virus (ZIKV) disease has become a global health emergency with devastating effects on public health. Recent evidences implicate the virus as an emergent neuropathological agent promoting serious pathologies of the human nervous system, that include destructive and malformation consequences such as development of ocular and fetal brain lesions, microcephaly in neonates, and Guillain–Barré syndrome (GBS) in adults. These neurological disorders of both central and peripheral nervous systems are thought to be associated to the neurotropic properties of the virus that has ability to infect neural stem cells as well as peripheral neurons, a hallmark of its pathogenicity. The presence of autoantibodies against gangliosides plays a pivotal role in the etiogenesis of GBS and a variety of neurological disorders. Gangliosides are a class of galactose-containing cerebrosides mainly expressed in nervous system tissues playing a critical role in the physiology of neural cells and neurogenesis. Herein, our findings indicate that patients at acute phase of ZIKV infection without any neurological signs show increased levels of IgG autoantibody against GD3 gangliosides, a class of glycolipid found to be highly expressed in neural stem cell acting in the maintenance of their self-renewal cellular capacity. It is possible that a pathological threshold of these antibodies is only acquired in secondary or subsequent infections. In the light of these evidences, we propose that the target of GD3 by autoimmune responses may possibly has an effect in the neuropathy and neurogenesis disorder seen during ZIKV infection.
Echevarria-Lima J, de Abreu Pereira D, de Oliveira TS, de Melo Espíndola O, Lima MA, Celestino Leite AC, Sandim V, Rodrigues Nascimento C, E Kalume D, B Zingali R. Protein Profile of Blood Monocytes is Altered in HTLV-1 Infected Patients: Implications for HAM/TSP Disease. Sci Rep. 2018 Sep 25;8(1):14354.
DOI: 10.1038/s41598-018-32324-2
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Human T-cell lymphotropic virus type-1 (HTLV-1) is the etiological agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The endothelial breakdown and migration of leukocytes, including monocytes, to the spinal cord are involved in HAM/TSP development. Monocytes from HTLV-1-infected individuals exhibit important functional differences when compared to cells from uninfected donors. Using proteomic shot gun strategy, performed by nanoACQUITY-UPLC system, we analyzed monocytes isolated from peripheral blood of asymptomatic carriers (AC), HAM/TSP and uninfected individuals. 534 proteins were identified among which 376 were quantified by ExpressionE software. Our study revealed a panel of changes in protein expression linked to HTLV-1 infection. Upregulation of heat shock proteins and downregulation of canonical histone expression were observed in monocytes from HTLV-1-infected patients. Moreover, expression of cytoskeleton proteins was increased in monocytes from HTLV-1-infected patients, mainly in those from HAM/TSP, which was confirmed by flow cytometry and fluorescence microscopy. Importantly, functional assays demonstrated that monocytes from HAM/TSP patients present higher ability for adhesion and transmigration thought endothelium than those from AC and uninfected individuals. The major changes on monocyte protein profile were detected in HAM/TSP patients, suggesting that these alterations exert a relevant role in the establishment of HAM/TSP.
Nunes CF, Nogueira JS, Vianna PHO, Ciambarella BT, Rodrigues PM, Miranda KR, Lobo LA, Domingues RMCP, Busch M, Atella GC, Vale AM, Bellio M, Nóbrega A, Canto FB, Fucs R. Probiotic treatment during neonatal age provides optimal protection against experimental asthma through the modulation of microbiota and T cells. Int Immunol. 2018 Apr 3;30(4):155-169.
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The incidence of allergic diseases, which increased to epidemic proportions in developed countries over the last few decades, has been correlated with altered gut microbiota colonization. Although probiotics may play a critical role in the restoration of gut homeostasis, their efficiency in the control of allergy is controversial. Here, we aimed to investigate the effects of probiotic treatment initiated at neonatal or adult ages on the suppression of experimental ovalbumin (OVA)-induced asthma. Neonatal or adult mice were orally treated with probiotic bacteria and subjected to OVA-induced allergy. Asthma-like symptoms, microbiota composition and frequencies of the total CD4+ T lymphocytes and CD4+Foxp3+ regulatory T (Treg) cells were evaluated in both groups. Probiotic administration to neonates, but not to adults, was necessary and sufficient for the absolute prevention of experimental allergen-induced sensitization. The neonatally acquired tolerance, transferrable to probiotic-untreated adult recipients by splenic cells from tolerant donors, was associated with modulation of gut bacterial composition, augmented levels of cecum butyrate and selective accumulation of Treg cells in the airways. Our findings reveal that a cross-talk between a healthy microbiota and qualitative features inherent to neonatal T cells, especially in the Treg cell subset, might support the beneficial effect of perinatal exposure to probiotic bacteria on the development of long-term tolerance to allergens.
Kitoko JZ, de Castro LL, Nascimento AP, Abreu SC, Cruz FF, Arantes AC, Xisto DG, Martins MA, Morales MM, Rocco PRM, Olsen PC. Therapeutic administration of bone marrow-derived mesenchymal stromal cells reduces airway inflammation without up-regulating Tregs in experimental asthma. Clin Exp Allergy. 2018 Feb;48(2):205-216.
DOI: 10.1111/cea.13048
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Prophylactic administration of mesenchymal stromal cells (MSCs) derived from adipose (AD-MSC) and bone marrow tissue (BM-MSC) in ovalbumin-induced asthma hinders inflammation in a Treg-dependent manner. It is uncertain whether MSCs act through Tregs when inflammation is already established in asthma induced by a clinically relevant allergen.
