Fatheia Hamza - Academia.edu (original) (raw)

Papers by Fatheia Hamza

Research paper thumbnail of Caenorhabditis elegans as an In Vivo Model for the Discovery and Development of Natural Plant-Based Antimicrobial Compounds

Pharmaceuticals

Antimicrobial resistance (AMR) due to the prevalence of multidrug-resistant (MDR) pathogens is ra... more Antimicrobial resistance (AMR) due to the prevalence of multidrug-resistant (MDR) pathogens is rapidly increasing worldwide, and the identification of new antimicrobial agents with innovative mechanisms of action is urgently required. Medicinal plants that have been utilised for centuries with minor side effects may hold great promise as sources of effective antimicrobial products. The free-living nematode Caenorhabditis elegans (C. elegans) is an excellent live infection model for the discovery and development of new antimicrobial compounds. However, while C. elegans has widely been utilised to explore the effectiveness and toxicity of synthetic antibiotics, it has not been used to a comparable extent for the analysis of natural products. By screening the PubMed database, we identified articles reporting the use of the C. elegans model for the identification of natural products endowed with antibacterial and antifungal potential, and we critically analysed their results. The studie...

Research paper thumbnail of Immunomodulatory Properties of Vitamin D in the Intestinal and Respiratory Systems

Nutrients

Vitamin D plays a crucial role in modulating the innate immune response by interacting with its i... more Vitamin D plays a crucial role in modulating the innate immune response by interacting with its intracellular receptor, VDR. In this review, we address vitamin D/VDR signaling and how it contributes to the regulation of intestinal and respiratory microbiota. We additionally review some components of the innate immune system, such as the barrier function of the pulmonary and intestinal epithelial membranes and secretion of mucus, with their respective modulation by vitamin D. We also explore the mechanisms by which this vitamin D/VDR signaling mounts an antimicrobial response through the transduction of microbial signals and the production of antimicrobial peptides that constitute one of the body’s first lines of defense against pathogens. Additionally, we highlight the role of vitamin D in clinical diseases, namely inflammatory bowel disease and acute respiratory distress syndrome, where excessive inflammatory responses and dysbiosis are hallmarks. Increasing evidence suggests that ...

Research paper thumbnail of Pulmonary Neutrophil Recruitment in Response to Inhaled LPS is Impaired in CD4 Deficient Mice

Objectiv e While the role of CD4+ regulatory T cells in the resolution of lung inflammation is we... more Objectiv e While the role of CD4+ regulatory T cells in the resolution of lung inflammation is well documented, their potential contribution to the onset of the inflammatory response has been largely neglected. Herein, we assessed the impact of germline CD4 deficiency on the alveolar macrophage (AMΦ)-neutrophil (PMN) axis in initiating the LPS-induced lung inflammation. Methods In vivo, The levels of AMΦ and PMN in bronchoalveolar lavage fluid (BALF) and tissue histopathology were compared in wild type (WT) and CD4-deficient (CD4−/−) mice at 4 hours after local LPS challenge (2–3 µg/g: intranasally). CD4 expression (flow cytometry) and representative functions of AMΦ (phagocytosis, cytokine secretion) and PMN (migration) of WT and CD4−/− mice were compared ex vivo. Results LPS increased PMN infiltration of alveoli in WT mice; a response severely blunted in CD4−/− mice. AMΦ isolated from WT mice captured more microbeads, but secreted less tumor necrosis factor-α, than AMΦ from CD4−/−...

Research paper thumbnail of Cellular and molecular profiling of primitive HSC subsets in umbilical cord blood samples: Implications for cellular therapy

Experimental Hematology, 2014

Background: Traditionally, hematopoietic stem/ progenitor cells (HSPCs) from bone-marrow, periphe... more Background: Traditionally, hematopoietic stem/ progenitor cells (HSPCs) from bone-marrow, peripheral blood and cord blood donors are used to cure obstinate blood disorders and to influence tolerance in graft-versus-host disease. The most primitive HSCs in mammals comprise the well characterized CD34 and the rare disused CD34 HSCs subsets. However, the defined analysis of the molecular nature of human CD34 and their relation to CD34 HSCs fractions has been held up by the lack of specific markers. Objectives: This study was intended to provide a thorough analysis using phenotypic, functional, and systemic approaches to decipher the cellular and the molecular signature of different HSPCs components, based on a comparative study combining both surface phenotypic markers and functional ALDH activity on human cord blood samples. Materials & Methods: Different HPSCs subsets were sorted from UCB and analyzed by flow cytometry, real time PCR, and proteomic techniques and their multi-differential capacity was assessed in vitro by colony forming unit assay Results: Evaluation of different HPSCs fractions revealed that CD34LinCD38ALDH and CD34LinCD38ALDHare the most primitive HPSCs populations as illustrated by their in vitro proliferation potentials by colony forming units and stemness related gene expression. Moreover, protein profiling performed on few samples showed that there is a high degree of similarities in the total number or resolved spots in both CD34 and CD3 gels indicating that perhaps CD34are also HSCs Conclusions: Our study confirmed that HPSCs is a heterogeneous population. The simultaneous expression of surface markers and ALDH activity indicated that the neglected LinCD34CD38ALDH HPSCs compartment included primitive HSCs and displayed similar functional and molecular characteristics to their counterpart LinCD34CD38ALDH. The common protein spots identified on HSCs subsets will eventually help in their selection for scientific and clinical applications.

Research paper thumbnail of Caenorhabditis elegans as an In Vivo Model for the Discovery and Development of Natural Plant-Based Antimicrobial Compounds

Pharmaceuticals

Antimicrobial resistance (AMR) due to the prevalence of multidrug-resistant (MDR) pathogens is ra... more Antimicrobial resistance (AMR) due to the prevalence of multidrug-resistant (MDR) pathogens is rapidly increasing worldwide, and the identification of new antimicrobial agents with innovative mechanisms of action is urgently required. Medicinal plants that have been utilised for centuries with minor side effects may hold great promise as sources of effective antimicrobial products. The free-living nematode Caenorhabditis elegans (C. elegans) is an excellent live infection model for the discovery and development of new antimicrobial compounds. However, while C. elegans has widely been utilised to explore the effectiveness and toxicity of synthetic antibiotics, it has not been used to a comparable extent for the analysis of natural products. By screening the PubMed database, we identified articles reporting the use of the C. elegans model for the identification of natural products endowed with antibacterial and antifungal potential, and we critically analysed their results. The studie...

Research paper thumbnail of Immunomodulatory Properties of Vitamin D in the Intestinal and Respiratory Systems

Nutrients

Vitamin D plays a crucial role in modulating the innate immune response by interacting with its i... more Vitamin D plays a crucial role in modulating the innate immune response by interacting with its intracellular receptor, VDR. In this review, we address vitamin D/VDR signaling and how it contributes to the regulation of intestinal and respiratory microbiota. We additionally review some components of the innate immune system, such as the barrier function of the pulmonary and intestinal epithelial membranes and secretion of mucus, with their respective modulation by vitamin D. We also explore the mechanisms by which this vitamin D/VDR signaling mounts an antimicrobial response through the transduction of microbial signals and the production of antimicrobial peptides that constitute one of the body’s first lines of defense against pathogens. Additionally, we highlight the role of vitamin D in clinical diseases, namely inflammatory bowel disease and acute respiratory distress syndrome, where excessive inflammatory responses and dysbiosis are hallmarks. Increasing evidence suggests that ...

Research paper thumbnail of Pulmonary Neutrophil Recruitment in Response to Inhaled LPS is Impaired in CD4 Deficient Mice

Objectiv e While the role of CD4+ regulatory T cells in the resolution of lung inflammation is we... more Objectiv e While the role of CD4+ regulatory T cells in the resolution of lung inflammation is well documented, their potential contribution to the onset of the inflammatory response has been largely neglected. Herein, we assessed the impact of germline CD4 deficiency on the alveolar macrophage (AMΦ)-neutrophil (PMN) axis in initiating the LPS-induced lung inflammation. Methods In vivo, The levels of AMΦ and PMN in bronchoalveolar lavage fluid (BALF) and tissue histopathology were compared in wild type (WT) and CD4-deficient (CD4−/−) mice at 4 hours after local LPS challenge (2–3 µg/g: intranasally). CD4 expression (flow cytometry) and representative functions of AMΦ (phagocytosis, cytokine secretion) and PMN (migration) of WT and CD4−/− mice were compared ex vivo. Results LPS increased PMN infiltration of alveoli in WT mice; a response severely blunted in CD4−/− mice. AMΦ isolated from WT mice captured more microbeads, but secreted less tumor necrosis factor-α, than AMΦ from CD4−/−...

Research paper thumbnail of Cellular and molecular profiling of primitive HSC subsets in umbilical cord blood samples: Implications for cellular therapy

Experimental Hematology, 2014

Background: Traditionally, hematopoietic stem/ progenitor cells (HSPCs) from bone-marrow, periphe... more Background: Traditionally, hematopoietic stem/ progenitor cells (HSPCs) from bone-marrow, peripheral blood and cord blood donors are used to cure obstinate blood disorders and to influence tolerance in graft-versus-host disease. The most primitive HSCs in mammals comprise the well characterized CD34 and the rare disused CD34 HSCs subsets. However, the defined analysis of the molecular nature of human CD34 and their relation to CD34 HSCs fractions has been held up by the lack of specific markers. Objectives: This study was intended to provide a thorough analysis using phenotypic, functional, and systemic approaches to decipher the cellular and the molecular signature of different HSPCs components, based on a comparative study combining both surface phenotypic markers and functional ALDH activity on human cord blood samples. Materials & Methods: Different HPSCs subsets were sorted from UCB and analyzed by flow cytometry, real time PCR, and proteomic techniques and their multi-differential capacity was assessed in vitro by colony forming unit assay Results: Evaluation of different HPSCs fractions revealed that CD34LinCD38ALDH and CD34LinCD38ALDHare the most primitive HPSCs populations as illustrated by their in vitro proliferation potentials by colony forming units and stemness related gene expression. Moreover, protein profiling performed on few samples showed that there is a high degree of similarities in the total number or resolved spots in both CD34 and CD3 gels indicating that perhaps CD34are also HSCs Conclusions: Our study confirmed that HPSCs is a heterogeneous population. The simultaneous expression of surface markers and ALDH activity indicated that the neglected LinCD34CD38ALDH HPSCs compartment included primitive HSCs and displayed similar functional and molecular characteristics to their counterpart LinCD34CD38ALDH. The common protein spots identified on HSCs subsets will eventually help in their selection for scientific and clinical applications.