Biology subjects

Ghimire, M.

Publications and source records attributed to Ghimire, M..

4 recordsLinked to original sources

bioRxiv2026

Dysregulation of anti-Ro60 B cell autoreactivity in systemic lupus erythematosus

To understand the dysregulation of autoreactive B cells in SLE, we tracked Ro60-specific cells in seropositive (SP) and seronegative (SN) patients and healthy donors (HD), using flow cytometry and monoclonal antibodies. Consistent with permissive central tolerance, Ro60+ naive B cells were present in all groups with increased anergy in HD. HD and SN SLE also had greatly decreased or absent Ro60+ memory and ASC, which were greatly increased in active SP SLE, thereby indicating defective distal tolerance in the latter group. Notably, Ro60 autoreactivity was strictly purged from naive-derived extra-follicular B cells in HD and SN SLE, but expanded in SP SLE, suggesting the importance of autoreactivity censoring in this pathway. SLE clustering of the distribution of Ro60+ B cells identified disease heterogeneity in tolerance enforcement in SLE. Finally, we demonstrate a much higher degree of polyreactivity against other lupus antigens in SLE Ro60+ naive cells, which is greatly attenuated in memory cells. Our work represents the first systematic study of antigen-specific autoreactive B cells and ASC in SLE. It enhances our understanding of human B cell tolerance and defines new approaches to measuring autoimmune activity in the course of SLE, including the assessment of immune resetting after B cell depletion therapies.

immunology↗

bioRxiv2026

Layer 5 and 6b extratelencephalic neurons encode distinct sound features in auditory cortex

Extratelencephalic (ET) neurons in layers (L)5 and 6b of the auditory cortex (ACtx) provide major corticofugal outputs to subcortical structures and contribute to auditory learning and experience-dependent plasticity. Although both ET subtypes innervate overlapping down-stream targets, they differ in morphology, intrinsic physiology, and molecular identity, suggesting distinct functional roles. However, their in vivo response properties remain incompletely characterized. Here, we used a projection-defined viral strategy to express GCaMP8s selectively in L5 and L6b ET neurons in mouse ACtx and recorded calcium activity during presentation of diverse acoustic stimuli. L5 ET neurons predominantly exhibited sound-evoked excitation, higher response sparseness, and greater trial-to-trial reliability than L6b ET neurons; these differences were most pronounced for pure tones and sinusoidally amplitude-modulated (sAM) noise. In contrast, L6b ET neurons frequently exhibited sound-evoked suppression, particularly for more complex stimuli (including sAM noise and spectrotemporal ripples). Unsupervised clustering identified separable temporal response motifs and tuning profiles. L5 ET neurons favored single-peaked frequency tuning and monotonic intensity tuning, whereas L6b ET neurons exhibited multi-peaked and complex frequency tuning, more non-monotonic intensity dependence, and stronger pairwise functional coupling (noise correlations). Together, these results support complementary corticofugal processing streams, with L5 ET neurons conveying more selective acoustic feature representations and L6b ET neurons conveying more integrative corticofugal signals.

neuroscience↗

bioRxiv2025

Micropropagation and Assessment of Genetic Homogeneity in Dendrobium moniliforme (L.) Sw. using Molecular Markers

Dendrobium moniliforme (L.) Sw., is a valuable medicinal orchid widely used as tonic. This study aimed to develop an effective protocol for micropropagation of D. moniliforme and to compare the genetic similarities of the micro-propagated plants to the wild plants using Random Amplified Polymorphic DNA (RAPD) and Inter Simple Sequence Repeats (ISSR) molecular markers. Healthy seeds were cultured on Murashige-Skoog (MS) medium, supplemented with various concentrations of auxins, cytokinins and coconut water for shoot and root development. Genetic homogeneity was assessed using ten primers of each RAPD and ISSR marker. MS media fortified with 10% coconut water was efficient for seed germination and protocorm development. Maximum number of shoots were produced on half strength MS (HMS) medium supplemented with 0.25 mg/L NAA and 10% coconut water (CW) i.e 22 shoots. FMS supplemented with 0.5 mg/L indole butyric acid (IBA) was found to be best as plant hormone for root induction, as it induced ten roots/shoot. RAPD and ISSR amplified a total of 15 and 5 homogeneous DNA fragments. This protocol demonstrates a reliable and efficient method for large-scale propagation and conservation of D. moniliforme, supporting its commercial and medicinal value. HighlightsDendrobium moniliforme was micro-propagated from seeds using MS medium. RAPD and ISSR markers confirmed its genetic stability. The study supports large-scale true-to-type propagation and conservation of these valuable medicinal orchids.

molecular biology↗

bioRxiv2022

Increased Pyramidal and VIP Neuronal Excitability in Primary Auditory Cortex Directly Correlates with Tinnitus Behavior

Tinnitus affects roughly 15-20% of the population while severely impacting 10% of those afflicted. Tinnitus pathology is multifactorial, generally initiated by damage to the auditory periphery, resulting in a cascade of maladaptive plastic changes at multiple levels of the central auditory neuraxis as well as limbic and non-auditory cortical centers. Using a well-established condition-suppression model of tinnitus, we measured tinnitus-related changes in the microcircuits of excitatory/inhibitory neurons onto layer 5 pyramidal neurons (PNs), as well as changes in the excitability of vasoactive intestinal peptide (VIP) neurons in primary auditory cortex (A1). Patch-clamp recordings from PNs in A1 slices showed tinnitus-related increases in spontaneous excitatory postsynaptic currents (sEPSCs) and decreases in spontaneous inhibitory postsynaptic currents (sIPSCs). Both measures were directly correlated to the rats behavioral evidence of tinnitus. Tinnitus-related changes in PN excitability were independent of changes in A1 excitatory or inhibitory cell numbers. VIP neurons, part of an A1 local circuit that can disinhibit layer 5 PNs, showed significant tinnitus-related increases in excitability that directly correlated with the rats behavioral tinnitus score. That PN and VIP changes directly correlated to tinnitus behavior, suggests an essential role in A1 tinnitus pathology. Tinnitus-related A1 changes were similar to findings in studies of neuropathic pain in somatosensory cortex suggesting a common pathology of these troublesome perceptual impairments. Improved understanding between excitatory, inhibitory and disinhibitory sensory cortical circuits can serve as a model for testing therapeutic approaches to the treatment of tinnitus and chronic pain. Key pointsO_LIIdentify tinnitus-related changes in synaptic function of specific neuronal subtypes in a reliable animal model of tinnitus. C_LIO_LIFinding show direct and indirect tinnitus-related losses of normal inhibitory function at A1 layer 5 pyramidal cells, and increased VIP excitability. C_LIO_LIFindings are similar to what has been shown for neuropathic pain suggesting that restoring normal inhibitory function at synaptic inputs onto A1 pyramidal neurons could conceptually reduce tinnitus discomfort. C_LI

neuroscience↗