bioRxiv Science⌕ Search

Biology subjects

Jovanovic, J.

Publications and source records attributed to Jovanovic, J..

3 recordsLinked to original sources

Electrical stimulation combined with p27Kip1 inactivation drives proliferative neurogenic reprogramming of Mueller glia in the adult mouse retina

Mueller glial reprogramming studies demonstrate that mammalian Mueller glia can be induced to proliferate and/or engage in neural differentiation, as occurs naturally in teleost fish. A major objective is the identification of combined strategies that promote both robust proliferation and neurogenesis. These studies would benefit from a translatable screening platform that enables controlled perturbation, maintained tissue context and longitudinal analysis, such as 3D culture for first tier analysis of reprogramming strategies. Here, we validate a 3D retinal culture for Mueller glial reprogramming studies by recapitulating key signatures of an in vivo reprogramming paradigm. Next, we find that electrical stimulation (E-stim) as a tunable, extrinsic cue is sufficient to activate endogenous Ascl1 expression, indicating a state transition favorable for neurogenesis, while Mueller glia-specific p27Kip1 inactivation promotes robust, prolonged proliferation. Utilization of the lineage-tracing proliferation-history reporter H3.1-iCOUNT enabled longitudinal proliferation analysis and assessment of reprogramming outcomes within the proliferative, Mueller-derived population. With this model, we find that E-stim and p27Kip1 inactivation in combination (ESPI) increases proliferation, endogenous Ascl1 expression, and neurogenesis of Mueller-derived cells across modalities. Together, this work establishes a 3D culture framework for discovery of combinatorial reprogramming strategies within a proliferative context and identifies ESPI as an efficient approach to proliferative, neurogenic Mueller glial reprogramming.

developmental biology↗

Diet gel-based oral drug delivery system for controlled dosing of small molecules for microglia depletion and inducible Cre recombination in mice

Small molecules like PLX5622 for microglia depletion and Tamoxifen for inducible Cre recombination are commonly used in mouse research. Traditional application methods, such as chow or oral gavage and injections, have limitations, including uncontrolled dosage and risk of injury. To address this issue, we have developed an alternative oral drug delivery system using a gel-based rodent maintenance diet that allows for controlled consumption and adjustment of dosage and is suitable for water-insoluble small molecules. We tested DietGel(R) 93M (93M) infused with PLX5622 (0.8 mg/g and 2.0 mg/g) in the Cx3cr1gfp/+ retinal microglia reporter mouse and Tamoxifen-infused 93M (0.3125 mg/g) in the Rlbp1-CreERT2;Rosaai14 mouse with an inducible tdTomato reporter in retinal Muller glia. Mice were single-caged and received daily batches of PLX5622-infused 93M over 14 days or Tamoxifen-infused 93M for one or three days followed by a 14-day observation period. Longitudinal scanning laser ophthalmoscopy in vivo and fixed tissue imaging were used to track GFP and tdTomato expression. Following evaluation of a suitable 93M consumption rate (g/d) to sustain body weight, the PLX5622-93M diet at both concentrations showed a 94% microglia depletion rate at 3 days and >99% after one and two weeks. The Tamoxifen-93M diet confirmed suitability for inducible Cre recombination, with significant treatment-time dependent efficacy and a positive correlation between total Tamoxifen dose and tdTomato expression. This study demonstrates that a diet gel-based drug delivery system offers a controllable and less invasive alternative to current drug application methods for PLX5622 and Tamoxifen.

cell biology↗

Between fishing and farming: palaeogenomic analyses reveal cross-cultural interactions triggered by the arrival of the Neolithic in the Danube Gorges

While early Neolithic populations in Europe were largely descended from early Aegean farmers, there is also evidence of episodic gene flow from local Mesolithic hunter-gatherers into early Neolithic communities. Exactly how and where this occurred is still unknown. Here we report direct evidence for admixture between the two groups at the Danube Gorges in Serbia. Analysis of palaeogenomes recovered from skeletons revealed that second-generation mixed individuals were buried amidst individuals whose ancestry was either exclusively Aegean Neolithic or exclusively local Mesolithic. The mixed ancestry is also reflected in a corresponding mosaic of grave goods. With its deep sequence of occupation and its unique dwellings that suggest at least semi-sedentary occupation since the late Mesolithic, the area of the Danube Gorges has been at the center of the debate about the contribution of Mesolithic societies to the Neolithisation of Europe. As suggested by our data, which were processed exclusively with uncertainty-aware bioinformatic tools, it may have been precisely in such contexts that close interactions between these societies were established, and Mesolithic ancestry and cultural elements were assimilated.

genomics↗