Host cells comprising alpha 1,2 mannosidase and culture methods thereof

What is this patent about?

’101 is related to the field of recombinant protein production and glycoprotein engineering. Specifically, it addresses the technical challenge of increasing the yield and specific productivity of therapeutic proteins in host cell cultures, such as CHO or human kidney fibrosarcoma cells, without relying solely on toxic chemical inducers like sodium butyrate.

The underlying idea behind ’101 is that the MAN1C1 enzyme, typically known for its role in trimming mannose sugars during N-linked glycosylation, acts as a metabolic bottleneck or regulator for overall protein output. By artificially boosting the activity of this specific mannosidase, the cell’s internal machinery is optimized to secrete higher quantities of a target glycoprotein, effectively mimicking the productivity gains of chemical inducers while avoiding their detrimental side effects on cell health.

The claims of ’101 focus on a genetically engineered host cell that is modified to simultaneously overexpress the MAN1C1 polypeptide and a specific glycoprotein of interest. The legal protection extends to cells where the MAN1C1 sequence shares at least 85% identity with SEQ ID NO: 2, provided that this overexpression results in a measurable increase in the specific productivity—defined as picograms of protein produced per cell per day—relative to a non-engineered control cell.

In practice, the invention is implemented by transfecting host cells with heterologous expression vectors or control sequences that upregulate the endogenous MAN1C1 gene. This genetic modification ensures that the mannose-trimming step in the endoplasmic reticulum is highly efficient, which the inventors discovered correlates with a significant rise in the secretion of complex proteins like erythropoietin or darbepoetin. The system can be further enhanced by adding traditional inducers, but the core genetic modification provides a baseline productivity boost of two- to three-fold even in their absence.

This approach differs from prior methods that focused on MAN1C1 solely for its ability to alter the carbohydrate structures on a protein's surface. While earlier research viewed mannosidases as tools for glycan remodeling, this invention identifies the enzyme as a driver of total protein volume. By targeting the MAN1C1 pathway, the invention provides a way to bypass the growth-inhibitory and toxic effects of histone deacetylase inhibitors, offering a more stable and sustainable engineering solution for large-scale biopharmaceutical manufacturing.