Biology subjects

Jafari, S.

Publications and source records attributed to Jafari, S..

10 recordsLinked to original sources

bioRxiv2025

Growth inhibitory effect of cerebrospinal fluid of multiple sclerosis patients on HFF2 cells

Multiple sclerosis (MS) is an autoimmune disease characterized by demyelination of the central nervous system (CNS). Occurrence of immunogenic cell death (ICD) in this disease and expression of ICD markers in the CSF of MS patients are documented. However, cytotoxic effect of MS patients cerebrospinal fluid (CSF) on the cells is not reported. To evaluate the cytotoxic impact of CSF from MS patients on cell viability, human foreskin fibroblast (HFF2) cells were treated with CSF samples from individuals with MS and healthy controls. The results inferred that patient-derived CSF significantly declined the survival of HFF2 cells in comparison to the CSF of healthy individuals. This observation implies a cytotoxic environment and characteristic of patients CSF, which could be due to the presence of cellular-damaging factors such as calreticulin (CRT) in the patients CSF. The cytotoxic environment of CSF might reflect ICD occurrence in CNS of the patients and also could explain the progressive essence of the disease.

neuroscience↗

bioRxiv2024

Polyunsaturated Fatty Acid - mediated Cellular Rejuvenation for Reversing Age-related Vision Decline

The retina is uniquely enriched in polyunsaturated fatty acids (PUFAs), which are primarily localized in cell membranes, where they govern membrane biophysical properties such as diffusion, permeability, domain formation, and curvature generation. During aging, alterations in lipid metabolism lead to reduced content of very long-chain PUFAs (VLC-PUFAs) in the retina, and this decline is associated with normal age-related visual decline and pathological age-related macular degeneration (AMD). ELOVL2 (Elongation of very-long-chain fatty acids-like 2) encodes a transmembrane protein that produces precursors to docosahexaenoic acid (DHA) and VLC-PUFAs, and methylation level of its promoter is currently the best predictor of chronological age. Here, we show that mice lacking ELOVL2-specific enzymatic activity (Elovl2C234W) have impaired contrast sensitivity and slower rod response recovery following bright light exposure. Intravitreal supplementation with the direct product of ELOVL2, 24:5n-3, in aged animals significantly improved visual function and reduced accumulation of ApoE, HTRA1 and complement proteins in sub-RPE deposits. At the molecular level, the gene expression pattern observed in retinas supplemented with 24:5n-3 exhibited a partial rejuvenation profile, including decreased expression of aging-related genes and a transcriptomic signature of younger retina. Finally, we present the first human genetic data showing significant association of several variants in the human ELOVL2 locus with the onset of intermediate AMD, underlying the translational significance of our findings. In sum, our study identifies novel therapeutic opportunities and defines ELOVL2 as a promising target for interventions aimed at preventing age-related vision loss.

molecular biology↗

bioRxiv2024

Annexin A1, Calreticulin and High Mobility Group Box 1 are elevated in Secondary Progressive Multiple Sclerosis: Does Immunogenic Cell Death Occur in Multiple Sclerosis?

Multiple sclerosis (MS) is a chronic neuroinflammatory diseases characterized by demyelination of the nerve fibers. Immunogenic cell death (ICD) is a process, during which damaged and stressed cells release danger-associated molecular patterns (DAMPs) activating immune responses. This study aimed to elucidate the induction of ICD in MS diseases. To achieve this goal, the level of DAMPs including Annexin A1, calreticulin and HMGB1 was measured in the cerebrospinal fluid (CSF) of a secondary progressive multiple sclerosis (SPMS) patient in comparison to control group. Results showed significant upregulation (more than two- fold) of Annexin A1, calreticulin and HMGB1 in the CSF of the patient. Although further studies are suggested in this regard, this data could imply induction of ICD in MS. The proposed ICD might trigger immune response against neural cells resulting in neuroinflammation and demyelination in CNS in MS. Our observation could suggest inclusion of ICD interfering treatments in routine MS therapy.

immunology↗

bioRxiv2023

Activity-dependent survival of odorant receptor neurons in ants

Olfaction is essential for complex social behavior in eusocial insects. To discriminate complex social cues, ants evolved an expanded number of odorant receptor (Or) genes. Unlike most insect species, mutations in the obligate odorant co-receptor gene orco lead to loss of [~]80% antennal lobe glomeruli in ants. However, its cellular mechanism remains unclear. Here we demonstrate that this surprising neuronal phenotype results from massive apoptosis of odorant receptor neurons (ORNs) in the mid- to late-stages of pupal development. Further bulk and single-nucleus transcriptome analysis show that, although the majority of orco-expressing ORNs die in orco mutants, a small proportion of them survive: they express ionotropic receptor (Ir) genes that form IR complexes. In addition, we found that some Or genes are expressed in mechanosensory neurons as well as non-neuronal cells, possibly due to the leaky regulation from nearby non-Or genes. Our findings suggest that chemosensory receptors are required for activity-dependent survival of developing ORNs in ants.

developmental biology↗

bioRxiv2021

Activity and stress during a critical period regulate olfactory sensory neuron differentiation

Here, we reveal that the regulation of Drosophila odorant receptor (OR) expression during the pupal stage is permissive and imprecise. We found that olfactory sensory neuron activity directly after hatching both directs and refines OR expression. We demonstrate that, as in mice, dLsd1 and Su(var)3-9 balance heterochromatin formation to direct OR expression. Neuronal activity induces dLsd1 and Su(var)3-9 expression, linking neuronal activity to OR expression. OR expression refinement shows a restricted duration, suggesting a gene regulatory critical period brings olfactory sensory neuron differentiation to an end. Consistent with a change in differentiation, stress during the critical period represses dLsd1 and Su(var)3-9 expression and makes the early permissive OR expression permanent. This induced permissive gene regulatory state makes OR expression resilient to stress later in life. Hence, during a critical period, OR activity feedback similar to in mouse OR selection, defines adult OR expression in Drosophila.

neuroscience↗

bioRxiv2020

The Effect of post Chlamydia Trachomatis Infection treatment on Reactive Oxygen Species and Sperm Parameters of Infertile Men

BackgroundChlamydia trachomatis (CT) infection is often mentioned as a silent disease. Reactive oxygen species (ROS) can also cause Sperm apoptosis and have negative impact on Sperm parameters. The objectives of this study were to elucidate the association between Sperm parameters and ROS caused by CT infections resulting in male Infertility as well as evaluating the role of antibiotic therapy. Materials and methodsA total of 848 infertile males having normal and abnormal Sperm parameters were included. After Semen sampling, the CT IgA were measured by Elisa and confirmed by Nested PCR. ROS was determined by Chemiluminescence. After treatment under the direct supervision of the private urologists. Then, the second Semen samples were taken and subjected to tests on Sperm parameters and ROS levels as assessed again. ResultsThe levels of ROS and morphology were improved following the treatments (P<0.05). Antibiotic therapy due to CT infection, could reduce ROS, improve normal morphology and recover some of Semen parameters. ConclusionsOur findings indicate that CT infection and Sperm parameters were associated with the rate of ROS in infertile men. However, after treatment, ROS value dropped allowing the recovery of certain Sperm parameters. Antibiotic therapy can improve some Semen quality parameters and treat the male Infertility. Reza Azmakan, rezaazmakan@yahoo.com, Department of Andrology, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran, https://orcid.org/0000-0001-6718-3348.

microbiology↗

bioRxiv2020

A critical period terminates the differentiation of olfactory sensory neurons

Development generates a vast number of neuron types and classes. When and how neuronal differentiation end is poorly understood. Here, we show that Drosophila olfactory sensory neurons (OSNs) matures during a critical period and reveal that the differentiation termination mechanism is similar to the mammalian odorant receptor (OR) choice mechanism. We first showed that initiation of Drosophila OR expression required heterochromatin opening and a H3K9me3 demethylase, Kdm4b. Further genetic studies demonstrated that Lsd1 and su(var)3-9, similar to mouse, were required to balance heterochromatin in order to stabilize OR expression. Expression analysis showed that Lsd1, su(var)3-9 increased and Kdm4b decreased during the first two days after eclosion. We further showed that environment changes during the period, but not after, caused permanent transformed Lsd1, su(var)3-9 and Kdm4b expression and altered OR gene regulation. These results together suggest the last step in OSN terminal differentiation to be a gene regulatory critical period.

neuroscience↗

bioRxiv2019

A simple CPG-based model to generate human hip moment pattern in walking by generating stiffness and equilibrium point trajectories

Equilibrium point hypothesis (its developed version named as referent control theory) presents a theory about how the central nerves system (CNS) generates human movements. On the other hand, it has been shown that nerves circuits known as central pattern generators (CPG) likely produce motor commands to the muscles in rhythmic motions. In the present study, we designed a bio-inspired walking model, by coupling double pendulum to CPGs that produces equilibrium and stiffness trajectories as reciprocal and co-activation commands. As a basic model, it is has been shown that this model can regenerate pattern of a hip moment in the swing phase by high correlation ({rho} = 0.970) with experimental data. Moreover, it has been reported that a global electromyography (EMG) minima occurs in the mid-swing phase when the hip is more flexed in comparison with the other leg. Our model showed that equilibrium and actual hip angle trajectories match each other in mid-swing, similar to the mentioned posture, that is consistent with previous findings. Such a model can be used in active exoskeletons and prosthesis to make proper active stiffness and torque.

bioengineering↗

bioRxiv2019

Hip retraction enhances walking stability on a ramp: an equilibrium point hypothesis-based study

Hip retraction is a phenomenon observed in human walking. The swing leg rotates backward at the end of the motion. Its positive effect on motion stability was reported in the literature based on some simple models for running or walking. In this study, it is shown that hip retraction angle increases in humans during their ascending and descending walk on a stair. In previous studies, hip retraction was modeled by defining a proper motion for the swing leg. According to the equilibrium point hypothesis, the central nervous system (CNS) defines only the equilibrium point(s) and stiffness(es) for body joint(s) to control the human motion. Human body motion emerges as its natural response as a result of the external forces and the defined equilibrium points of joints. Considering the hip torque as a spring-like model with an equilibrium point and stiffness, this study revealed that the hip retraction can be generated by the natural response of the swing leg. Besides, the stabilizing effect of hip retraction was demonstrated by a model for humans ascending and descending walking on a ramp with a range of positive and negative angles, respectively. The findings suggest that the CNS needs to define equilibrium point just ahead of the stance leg to take advantage of the hip retraction effect on ascending and descending walks on a ramp.

bioengineering↗

bioRxiv2019

Application of Different Types of Lactic Acid Bacteria Inoculant on Ensiled Rice Straw; Effects on Silage Quality, Rumen Fermentation, Methane Production and Microbial Population

Bacterial inoculants are known to improve quality of silage. The objectives of the present study were to evaluate the effects of different types of lactic acid bacteria (LAB; L. plantarum, L. salivarius, L. reuteri, L. brevis and S. bovis) inoculation (106 g-1 DM) on rice straw silage quality and to examine these effects on ruminal fermentation characteristics, digestibility and microbial populations in an in vitro condition. Inoculated rice straw was ensiled for 15 and 30 days. For in vitro study, rumen liquor was obtained from two rumen fistulated mature cows fed on mixed forage and concentrate at 60:40 ratio twice daily. Inoculation of LAB improved (P0.05) the rice straw silage quality such as increased dry matter and crude protein contents, decreased pH and butyric acid, and increased propionic acid and LAB contents especially after 30 days of ensiling. Results from in vitro study revealed that addition of LAB to the rice straw silage improved fermentation characteristics such as increased total volatile fatty acids and dry matter digestibility (P0.05). LAB treatments also decreased methane production and methane/total gas ratio after 15 and 30 days of ensiling. From the rumen microbial population perspective, cellulolytic, and fungal zoospores were enhanced while protozoa and methanogens were decreased by the LAB treatments. Based on these results, it could be concluded that inoculating rice straw silage with LAB (especially for L. plantarum and S. bovis) improved silage quality, rumen fermentation parameters and microbial populations in vitro. However, in vivo studies need to confirm those effects.

physiology↗