Biology subjects

Keck, M.

Publications and source records attributed to Keck, M..

5 recordsLinked to original sources

bioRxiv2026

Enhanced 3D Osteogenic Differentiation of Encapsulated Human MSCs in Hyaluronic Acid Core Alginate Shell Capsules under Dynamic Culture Conditions

The growing demand for three-dimensional (3D) in vitro models that accurately replicate human tissue to investigate disease mechanisms, enable tissue replacement, and support drug testing is driving the need for more advanced manufacturing platforms. Mesenchymal stem/stromal cells (MSCs) are promising candidates for tissue engineering and stem cell therapies due to their regenerative potential and ethical advantages. However, the reproducible and scalable production of 3D models that truly mimic the human complexity and function poses a major challenge. To address these challenges, we have developed a scalable and semi-automated 3D differentiation process for generating osteogenic microtissue derived from MSCs encapsulated in core-shell capsules (CSCs). To validate material-dependent, osteo-inductive effects of hyaluronic acid (HA), we systematically characterised our encapsulation process with regard to CSC integrity, spheroid formation and viability, as well as diffusion and shear thinning properties. Osteogenic differentiation was performed in static and dynamic culture, using either conventional 6-well plate format or a rotating wall vessel bioreactor. HA-CSCs were compared with inert carboxymethyl cellulose (CMC)-CSCs. In addition, hypoxic culture condition and the implementation of human platelet lysate (hPL) further supported physiological relevance. HA led to the formation of larger spheroids with high cell viability and increased metabolic activity compared to CMC. Calcium phosphate deposition within the extracellular matrix (ECM) and elevated ALP activity confirmed successful osteogenesis in all conditions. Furthermore, both HA and dynamic culture promote osteogenesis, and when combined, synergistically enhance the osteogenic differentiation. In conclusion, we present a semi-automated, high-throughput and xeno-free platform process for the 3D differentiation of MSCs towards osteogenic lineage. By integrating HA, hypoxia and dynamic culture conditions, this capsule-based system enhances the physiological relevance, enabling advanced in vitro disease modelling, drug testing, and scalable microtissue generation while reducing reliance on animal models.

bioengineering↗

bioRxiv2025

In vitro and in vivo Antiviral Activity of the Acyclic Nucleoside Phosphonate Prodrug LAVR-289 against Poxvirus and African Swine Fever Virus Replication

Poxviruses are double-stranded DNA viruses including relevant zoonotic pathogens with high morbidity. Although African swine fever virus (ASFV) belongs to the Asfarviridae family and is not strictly classified as a member of the Poxviridae, both fall within the same class of Pokkesviricetes that replicate in the cytoplasm, and some poxviruses pose potential biological warfare threats. Among compounds targeting these viruses, acyclic nucleoside phosphonate prodrugs are nucleoside analogues inhibitors of viral DNA polymerases that have been identified as promising agents. However, some limitations related to their toxicity and the rapid emergence of resistance highlight the need for new antiviral molecules. In this study, the new nucleoside analogue LAVR-289 was shown to effectively inhibit the viral replication by intervening early in the viral replication step, targeting a specific domain of the poxvirus DNA polymerase. Using monkeypox virus models, the subcutaneous or oral administration of LAVR-289 demonstrates protective efficacy in infected animal models without toxicity or behavioral modification. The stability in vivo, long shelf-life and efficacy make LAVR-289 a promising candidate for further development and stockpiling as a medical countermeasure against dsDNA virus outbreaks. Its broad-spectrum efficacy is a real asset in a context of recurrent viral epidemics, risk of bioterrorism and emergence of resistance strains in the population. HighlightsO_LILAVR-289 is a unique acyclic nucleoside phosphonate prodrug targeting viral DNA polymerases. C_LIO_LILAVR-289 displays antiviral activity against dsDNA viruses, ASFV and poxviruses. C_LIO_LIFirst report of in vivo evaluation of LAVR-289 against MPXV by subcutaneous and oral administration. C_LIO_LILAVR-289 reduces clinical signs and increase survival in animal models. C_LI

microbiology↗

bioRxiv2021

A screening pipeline identifies a broad-spectrum inhibitor of bacterial AB toxins with cross protection against influenza A virus H1N1 and SARS-CoV-2

A challenge for the development of host-targeted anti-infectives against a large spectrum of AB-like toxin-producing bacteria encompasses the identification of chemical compounds corrupting toxin transport through both endolysosomal and retrograde pathways. Here, we performed a high-throughput screening of small chemical compounds blocking active Rac1 proteasomal degradation triggered by the Cytotoxic Necrotizing Factor-1 (CNF1) toxin, followed by orthogonal screens against two AB toxins hijacking defined endolysosomal (Diphtheria toxin) or retrograde (Shiga-like toxin 1) pathways to intoxicate cells. This led to the identification of the molecule N-(3,3-diphenylpropyl)-1-propyl-4-piperidinamine, referred to as C910. This compound induces the swelling of EEA1-positive early endosomes, in absence of PIKfyve kinase inhibition, and disturbs the trafficking of CNF1 and the B-subunit of Shiga toxin along the endolysosomal or retrograde pathways, respectively. Together, we show that C910 protects cells against 8 bacterial AB toxins including large clostridial glucosylating toxins from Clostridium difficile. Of interest, C910 also reduced viral infection in vitro including influenza A virus subtype H1N1 and SARS-CoV-2. Moreover, parenteral administration of C910 to the mice resulted in its accumulation in lung tissues and reduced lethal influenza infection.

microbiology↗

bioRxiv2021

Combination of High Dose Rate Radiations (10X FFF/2400 MU/min/10 MV X-rays) and Paclitaxel Selectively Eliminates Melanoma Cells

PurposeMelanoma is one of the most aggressive cancer with 1.6% of total cancer deaths in United States. In recent years treatment options for metastatic melanoma have been improved by the FDA approval of new therapeutic agents. However, these inhibitors based therapies are non-specific and have severe toxicities including hyperkeratosis, photosensitivity, hepatitis, arthralgia and fatigue. The aim of this study is to determine the synthetic lethal effect (paclitaxel and radiations) on melanoma cells and reduce the total radiation doses by increasing the dose rates up to 2400 MU/min. MethodsWe previously reported a radiation treatment (10 MV x-rays, 10X-FFF, dose rate 2400MU/min, low total dose 0.5 Gy) that kills melanoma cells with 80% survival of normal HEM in vitro. In this study we extended the radiation cycle up to four and include paclitaxel treatment to study the synthetic lethal effect on melanoma and two additional normal primary cells, HDF and HEK. Cells were treated with paclitaxel prior to radiations of dose rate of 400 and 2400 MU/min with total radiation dose of only 0.5 Gy. To study induction of apoptosis and cell death, mitochondria respiration assay, DNA damage assay and colony formation assay were performed. ResultsFour days of consequent radiation treatment with paclitaxel significantly reduces the survival of melanoma cells by inducing of apoptosis and mitochondrial damages. After treatment, excessive DNA damage in melanoma cells leads to increase in expression of pro-apoptotic genes (Casp3) and decrease in expression of DNA repair gene (PARP1) and anti-apoptotic gene (Bcl2) to activate apoptosis pathway. Combination of paclitaxel and radiations reduces the survival of melanoma cells colonies when compared to radiation alone. ConclusionOur study indicates radiations with paclitaxel has potential synthetic lethal effect on melanoma cells and can be develop as therapy for melanoma without having toxicities or harmful effects to normal primary skin cells.

cancer biology↗

bioRxiv2021

A new variant of ASIC2 mediates sodium retention in nephrotic syndrome

Idiopathic nephrotic syndrome (INS) is characterized by proteinuria and renal Na retention leading to oedema. This Na retention is usually attributed to epithelial sodium channel (ENaC) activation following plasma aldosterone increase. However, most nephrotic patients show normal aldosterone levels. Using a corticosteroid-clamped rat model of INS (CC-PAN), we showed that the observed electrogenic and amiloride-sensitive Na retention could not be attributed to ENaC. We, then, identified a truncated variant of acid sensing ion channel 2b (ASIC2b) that induced sustained acid-stimulated sodium currents when co-expressed with ASIC2a. Interestingly, CC-PAN nephrotic ASIC2b-null rats did not develop sodium retention. We finally showed that expression of the truncated ASIC2b in kidney was dependent on the presence of albumin in the tubule lumen and activation of ERK in renal cells. Finally, the presence of ASIC2 mRNA was also detected in kidney biopsies from patients with INS but in any of the patients with other renal diseases. We have, therefore, identified a novel variant of ASIC2b responsible for the renal Na retention in the pathological context of INS.

pathology↗