Biology subjects

Bello, G.

Publications and source records attributed to Bello, G..

7 recordsLinked to original sources

bioRxiv2026

Investigation of sterile hydrogels as topical vehicles for APOSEC™, a stressed peripheral blood mononuclear cell secretome for the treatment of poorly healing wounds

APOSECTM, a complex mixture of secreted proteins, lipids, and extracellular vesicles from stressed peripheral blood monocytes, is currently in clinical trials for the treatment of chronic, poorly healing wounds. When applied to open wounds, 1 mL reconstituted APOSECTM lyophilisate is syringe-mixed with 3 g sterile hydrogel prior to administration. This study investigates the pharmaceutical performance of this novel administration system. A gel formulation (APOgel) was developed for terminal sterilisation in pre-filled syringes with post-sterilisation viscosity ([~]325-350{square}Pa*s at 1{square}s-1) comparable to a commercial benchmark gel. Syringe mixing of APOgel with a liquid APOSECTM surrogate (3:1) reduced viscosity by [~]67% but was highly reproducible across different operators (CV < 6%). Administration of three sequential dose units of the mixture from the syringe revealed an [~]20% higher content of active ingredients in the first and final dispensed compared to the middle unit, indicating non-uniform mixing in the closed syringe system. In vitro release studies over 72{square}h showed a 32% and 48% higher release of a small molecule marker and total proteins from the sterile APOgel compared to the benchmark gel as well as more pronounced gel swelling. However, efficacy studies in a murine wound healing model showed no significant difference between APOgel and the benchmark. These findings indicate that terminal sterilisation of gels for topical applications may provide benefits for more rapid release of active agents but syringe mixing of gels and a liquid requires optimisation to ensure uniform drug distribution. HighlightsO_LIAn autoclavable hydrogel for APOSECTM delivery was developed C_LIO_LIA novel syringe-mixing system for combining a gel with a liquid with subsequent dispensing of different volume units showed non-homogenous active ingredient distribution C_LIO_LIFinal optimised APOSECTM-APOgel formulation maintains functional wound-healing efficacy C_LI

pharmacology and toxicology↗

bioRxiv2022

Absolute scattering length density profile of liposome bilayers obtained by SAXS combined with GIXOS - a tool to determine model biomembrane structure

Lipid membranes play an essential role in biology, acting as host matrices for biomolecules like proteins and facilitating their functions. Their structures, and structural responses to physiologically relevant interactions, i.e. with membrane proteins, provide key information for understanding biophysical mechanisms. Hence, there is a crucial need of methods to understand the effects of membrane host molecules on the lipid bilayer structure. Here, we present a purely experimental method for obtaining the absolute scattering length density (SLD) profile and the area per lipid of liposomal bilayers, by aiding the analysis of small angle X-ray scattering (SAXS) data with the volume of bare headgroups obtained from fast (20-120s) grazing incidence off-specular scattering (GIXOS) data from monolayers of the same model membrane lipid composition. The GIXOS data experimentally demonstrate that the variation of the bare headgroup volume upon lipid packing density change is small enough to allow its usage as a reference value without knowing the lipid packing stage in a bilayer. This approach also bares the advantage that the reference volume is obtained at the same aqueous environment as used for the model membrane bilayers. We demonstrate the validity of this method using several typical membrane compositions, as well as one example of a phospholipid membrane with an incorporated transmembrane peptide. This methodology allows to obtain absolute scale values rather than relative scale by using solely X-ray-based instrumentation, retaining a similar resolution of SAXS experiments. The presented method has high potential to understand structural effects of membrane proteins on the biomembrane structure.

biophysics↗

bioRxiv2021

A potential SARS-CoV-2 variant of interest (VOI) harboring mutation E484K in the Spike protein was identified within lineage B.1.1.33 circulating in Brazil

The SARS-CoV-2 epidemic in Brazil was dominated by two lineages designated as B.1.1.28 and B.1.1.33. Two SARS-CoV-2 variants harboring mutations at the receptor-binding domain of the Spike (S) protein, designated as lineages P.1 and P.2, evolved within lineage B.1.1.28 and are rapidly spreading in Brazil. Lineage P.1 is considered a Variant of Concern (VOC) because of the presence of multiple mutations in the S protein (including K417T, E484K, N501Y), while lineage P.2 only harbors mutation S:E484K and is considered a Variant of Interest (VOI). Here we report the identification of a new SARS-CoV-2 VOI within lineage B.1.1.33 that also harbors mutation S:E484K and was detected in Brazil between November 2020 and February 2021. This VOI displayed four non-synonymous lineage-defining mutations (NSP3:A1711V, NSP6:F36L, S:E484K, and NS7b:E33A) and was designated as lineage N.9. The VOI N.9 probably emerged in August 2020 and has spread across different Brazilian states from the Southeast, South, North and Northeast regions.

microbiology↗

bioRxiv2020

Genomic surveillance of SARS-CoV-2 reveals community transmission of a major lineage during the early pandemic phase in Brazil

Despite all efforts to control the COVID-19 spread, the SARS-CoV-2 reached South America within three months after its first detection in China, and Brazil became one of the hotspots of COVID-19 in the world. Several SARS-CoV-2 lineages have been identified and some local clusters have been described in this early pandemic phase in Western countries. Here we investigated the genetic diversity of SARS-CoV-2 during the early phase (late February to late April) of the epidemic in Brazil. Phylogenetic analyses revealed multiple introductions of SARS-CoV-2 in Brazil and the community transmission of a major B.1.1 lineage defined by two amino acid substitutions in the Nucleocapsid and ORF6. This SARS-CoV-2 Brazilian lineage was probably established during February 2020 and rapidly spread through the country, reaching different Brazilian regions by the middle of March 2020. Our study also supports occasional exportations of this Brazilian B.1.1 lineage to neighboring South American countries and to more distant countries before the implementation of international air travels restrictions in Brazil.

evolutionary biology↗

bioRxiv2019

HIV-1 controllers exhibit an enhanced antiviral state characterized by overexpression of p21 and MCPIP1

Some multifunctional cellular proteins, as the monocyte chemotactic protein-induced protein 1 (MCPIP1) and the cyclin-dependent kinase inhibitor p21, have also shown to be able to modulate the cellular susceptibility to the human immunodeficiency virus type 1 (HIV-1). Several studies described that p21 is expressed at high levels ex vivo in cells from individuals who naturally control HIV-1 replication (HIC). The expression level of MCPIP1 in HIC was never described before, but a recent study in a model of renal carcinoma cells showed that MCPIP1 overexpression was associated with an increase of both p21 transcripts and proteins levels. Here, we explored the potential associations between MCPIP1 and p21 expression, as well as with cellular activation in HIC, sustaining undetectable (elite controllers - EC) or low (viremic controllers - VC) viral loads. We found a selective upregulation of MCPIP1 and p21 mRNA levels in PBMC from HIC compared with both ART- suppressed and HIV-negative control groups (P [≤] 0.02) and a strong positive correlation (r [≥] 0.57; P [≤] 0.014) between expressions of both transcripts independently of the VL, treatment condition and HIV status. The mRNA levels of p21, but not of MCPIP1, were positively correlated with activated CD4+ T cells levels in HIC and EC (r [≥] 0.53; P [≤] 0.017). In relation to the monocyte activation, the mRNA levels of both p21 (r = 0.74; P = 0.005) and MCPIP1 (r = 0.58; P = 0.040) were positively correlated with plasmatic levels of sCD14 only in EC. Multivariate analysis confirmed the association between MCPIP1 and p21 mRNA levels, and between the latter with the frequency of activated CD4+ T cells. These data show for the first time the simultaneous overexpression and positive correlation of MCPIP1 and p21 transcripts in the setting of natural suppression of HIV-1 replication in vivo. The positive correlation between MCPIP1 and p21 transcripts supports a common regulatory pathway connecting these multifunctional host factors and a possible synergistic effect on HIV-1 replication control. Pharmacological manipulation of these cellular proteins may open novel therapeutic perspectives to prevent HIV-1 replication and disease progression.

immunology↗

bioRxiv2019

Distinct YFV lineages co-circulated in the Central-Western and Southeastern Brazilian regions from 2015 to 2018

The current outbreak of yellow fever virus (YFV) that is afflicting Brazil since the end of 2016 probably originated from a re-introduction of YFV from endemic areas into the non-endemic Southeastern Brazil. However, the lack of genomic sequences from endemic regions hinders the tracking of YFVs dissemination routes. We assessed the origin and spread of the ongoing YFV Brazilian outbreak analyzing a new set of YFV strains infecting humans, non-human primates (NHP) and mosquitoes sampled across five Brazilian states from endemic and non-endemic regions between 2015 and 2018. We found two YFV sub-clade 1E lineages circulating in NHP from Goias state (GO), resulting from independent viral introductions into the Araguaia tributary river basin: while the strain from 2017 clustered intermingled with Venezuelan YFV strains from 2000, the YFV strain sampled in 2015 clustered with sequences of the current YFV outbreak in the Brazilian Southeastern region (named YFV2015-2018 lineage), displaying the same molecular signature associated to the current YFV outbreak. After its introduction in GO at around mid-2014, the YFV2015-2018 lineage followed two paths of dissemination outside GO, originating two major YFV sub-lineages: 1) the YFVMG/ES/RJ sub-lineage spread sequentially from the eastern area of Minas Gerais state to Espirito Santo and then to Rio de Janeiro states, following the Southeast Atlantic basin; 2) the YFVMG/SP sub-lineage spread from the southwestern area of Minas Gerais to the metropolitan region of Sao Paulo state, following the Parana basin. These results indicate the ongoing YFV outbreak in Southeastern Brazil originated from a dissemination event from GO almost two years before its recognition at the end of 2016. From GO this lineage was introduced in Minas Gerais state at least two times, originating two sub-lineages that followed different routes towards densely populated areas. The spread of YFV outside endemic regions for at least four years stresses the imperative importance of the continuous monitoring of YFV to aid decision-making for effective control policies aiming the increase of vaccination coverage to avoid the YFV transmission in densely populated urban centers.

epidemiology↗

bioRxiv2017

Genomic and structural features of the Yellow Fever virus from the 2016-2017 Brazilian outbreak

Brazil has been suffering a severe sylvatic epidemic of yellow fever virus (YFV) since late 2016. Analysis of full-length YFV genomes from all hosts involved in the Brazilian 2017 outbreak reveals that they belong to sub-lineage 1E within modern-lineage, but display several unique amino acid substitutions in highly conserved positions at NS3 and NS5 viral proteins. Evolutionary analyses indicate that YFV carrying that set of amino acid substitution circulates in the Southern Brazilian region for several months before being detected in December 2016. Structural and selection analyses support that some of these substitutions were under positive selection and could impact enzyme structure and function. Altogether, this evidence demonstrated that the current Brazilian YFV carries unique amino acid signatures in the non-structural proteins and support the hypothesis that those substitutions may be affecting the viral fitness and transmissibility.

microbiology↗