Biology subjects

Doll, T.

Publications and source records attributed to Doll, T..

4 recordsLinked to original sources

bioRxiv2026

GPNMB enables lysosomal adaptation required for myelin clearance and nerve regeneration after peripheral nerve injury

Recovery from peripheral nerve injury involves coordinated axonal and immune repair programs that promote tissue regeneration. However, the mechanisms regulating immune-mediated repair remain incompletely understood. Here, we demonstrate that glycoprotein non-metastatic melanoma protein B (GPNMB) is a key regulator of repair processes following peripheral nerve injury. In a mouse sciatic nerve crush model, loss of Gpnmb impaired functional recovery after injury. MRI and histological analyses revealed persistent myelin debris accumulation, defective debris clearance, and impaired macrophage lysosomal function within injured nerves. Mechanistic studies showed that GPNMB-deficient human iPSC-derived macrophages exhibited impaired lysosomal adaptation, reduced lysosomal fitness, and defective processing of myelin-associated cargo, resulting in inefficient degradation of injury-associated material. These defects were accompanied by impaired acquisition of repair-associated cellular programs. Together, our findings identify GPNMB as a critical regulator of lysosome-dependent repair programs during nerve regeneration and demonstrate that efficient GPNMB-dependent myelin processing is required for functional recovery following peripheral nerve injury.

neuroscience↗

bioRxiv2025

Induced pluripotent stem cell-derived human macrophages as an infection model for Trypanosoma cruzi

Chagas disease, caused by the parasite Trypanosoma cruzi, affects millions of people globally. Unfortunately, the available treatment options, especially for the chronic stage of the disease, are suboptimal. Given the chronic nature of the disease and the elusive nature of the parasite, there is a high need for new and safer drugs that deliver sterile cure. Posaconazole was a promising lead in the drug discovery pipeline but ultimately failed in clinical trials due to patient relapses. This failure illustrates the need for a drug screening assay that can predict sterile cure by assessing recrudescence after treatment. Here, we used human induced pluripotent stem cell (iPSC)-derived macrophages (iMACs) as host cells for T. cruzi. The iMACs were highly susceptible to infection by the parasites. By combining red fluorescent protein (RFP)-expressing iMACs with mNeonGreen-expressing T. cruzi, we were able to monitor the dynamics of the infection through live cell imaging. The activity of the compounds benznidazole and posaconazole was consistent with the results of an established infection system using mouse primary macrophages. The post-mitotic nature of iMACs makes them suitable host cells for long-term assays needed to assess recrudescence of parasites. Moreover, their human origin, stable genetic background, and capacity for genetic modification make the iMACs excellent host cells for studying host-pathogen interaction. Author summaryThe parasite Trypanosoma cruzi, the causative agent of Chagas disease, is a global health concern affecting millions each year. Infection with T. cruzi can cause chronic disease, often remaining asymptomatic for decades before resulting in severe cardiac or gastro-intestinal pathologies. To date, only benznidazole and nifurtimox are used for treatment of the infection, but both drugs are suboptimal for curing the chronic stage. Posaconazole showed great promise in preclinical studies but failed to achieve sterile cure in clinical trials, causing patient relapses. These disappointing results underline the need for drug screening assays able to predict sterile cure by evaluating recrudescence post-treatment. We used human induced pluripotent stem cell derived macrophages as host cells for T. cruzi and testing of trypanocidal compounds. This model can be used for long-term in vitro screening assays to find new drug candidates against Chagas disease. The human origin of these cells combined with the possibility of upscaling their production make them great host cells for drug screening campaigns.

microbiology↗

bioRxiv2023

Induced pluripotent stem cell-derived human macrophages as an infection model for Leishmania donovani

The parasite Leishmania donovani is one of the species causing visceral leishmaniasis in humans, a deadly infection claiming up to 40,000 lives each year. The current drugs for leishmaniasis treatment have severe drawbacks and there is an urgent need to find new anti-leishmanial compounds. However, the search for drug candidates is complicated by the intracellular lifestyle of Leishmania. Here, we investigate the use of human induced pluripotent stem cell (iPS)-derived macrophages (iMACs) as host cells for L. donovani. iMACs obtained through embryoid body differentiation were infected with L. donovani promastigotes, and high-content imaging techniques were used to optimise the iMACs seeding density and multiplicity of infection, allowing us to reach infection rates up to 70% five days after infection. IC50 values obtained for miltefosine and amphotericin B using the infected iMACs or mouse peritoneal macrophages as host cells were comparable and in agreement with the literature, showing the potential of iMACs as an infection model for drug screening. Author SummaryYearly, up two million people in poverty-stricken areas contract leishmaniasis, a disease caused by parasites of the genus Leishmania. When an infected sandfly takes a blood meal, Leishmania parasites enter the host where they are taken up by macrophages. Inside the macrophage, Leishmania parasites establish a niche where they can proliferate. Although this infection often leads to disability or death, the drugs currently available are lacking due to toxic side effects, high expenses or difficulties in usage. Drug screening assays that are currently used for compound screening often rely on mouse peritoneal macrophages. We have generated human induced pluripotent stem cell derived macrophages and used these as new host cells for Leishmania donovani in the testing of anti-leishmanial compounds. This model has many advantages. For one, it allows us to work with human cells, mimicking the natural infection more closely than possible with murine cells. Secondly, it allows to obtain bigger batches of uniform cells for screening campaigns. Finally, this approach aligns with the principle of 3R, replacing the use of animals for cultivation of Leishmania and drug screening purposes.

cell biology↗

bioRxiv2021

Persistence of Plasmodium cynomolgi hypnozoites in cynomolgus monkey iPS-derived hepatocytes

Plasmodium cynomolgi (Pc) is one of the few parasite species that forms quiescent liver stage parasites known as hypnozoites and is therefore a suitable model for Plasmodium vivax. Very little is known about liver stage dormancy, which hampers the search for compounds with anti-hypnozoite activity. Here, we present the development of a Pc in vitro infection model using stem cell-derived hepatocytes from Macaca fascicularis. IPS cells were established on feeder free condition and differentiated into hepatocytes via inducible overexpression of key transcription factors. The generated hepatocytes were infected with Pc sporozoites and hypnozoite formation as well as schizont development were confirmed by immunofluorescence. This system is a promising tool to study the mechanisms underlying liver stage dormancy and facilitate drug discovery against hypnozoites.

cell biology↗