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

What is this patent about?

’210 is related to the field of recombinant protein production and methods for enhancing the yield of glycoproteins in cell culture. In the biopharmaceutical industry, increasing the specific productivity of host cells is a critical objective for reducing manufacturing costs and expanding capacity. While chemical inducers like sodium butyrate are commonly used to boost protein yields, their utility is often limited by significant cellular toxicity and a lack of clarity regarding their precise molecular mechanisms.

The underlying idea behind ’210 is that the MAN1C1 enzyme, typically known for its role in trimming mannose sugars during N-linked glycosylation, serves as a metabolic bottleneck for protein secretion. The inventors discovered that upregulating this specific enzyme—which is naturally involved in the endoplasmic reticulum quality control and degradation pathways—unexpectedly drives a substantial increase in the amount of recombinant protein a cell can produce and secrete, independent of the toxic effects associated with traditional chemical inducers.

The claims of ’210 focus on an isolated host cell that has been genetically engineered to overexpress both its native alpha 1,2 mannosidase (MAN1C1) and a specific glycoprotein of interest. The scope of the invention requires that the MAN1C1 is expressed at a high enough level to measurably increase the specific productivity, defined as the mass of glycoprotein produced per cell per day, relative to a standard, non-engineered version of the same host cell.

In practice, this is achieved by transfecting host cells, such as CHO or human HT1080 cells, with expression vectors containing the MAN1C1 gene or by using heterologous control sequences to upregulate the endogenous gene. The invention demonstrates that overexpressing this enzyme can lead to a 2-3 fold increase in the production of therapeutic proteins like erythropoietin (EPO) even without the addition of sodium butyrate. When used in conjunction with inducers, the effect is even more pronounced, as MAN1C1 appears to be a primary genetic mediator of the productivity gains usually triggered by those chemicals.

This approach differs from prior art by shifting the focus from general transcriptional enhancers to a specific enzymatic pathway in the glycoprotein processing machinery. While previous methods relied on inhibiting histone deacetylases to broadly alter gene expression—often leading to cell cycle arrest or apoptosis—the present invention targets the protein folding and quality control environment. By optimizing the mannose-trimming step, the host cell becomes more efficient at processing nascent proteins, thereby bypassing the degradation responses that typically limit high-volume recombinant expression.