In terms of a neutral link profile, it needs to, above everything else, appear natural. If your link profile consisted of nothing but dofollow links, then this could be considered unnatural.
There is no limit to the number of links that denote something odd, per se, but you must step back and look at it from Google's eyes. Would they want to see 400 article links all coming from submissions at the same site? Would this suggest article spam? Are these articles each going to be high quality?
It is much more natural to have a few links from a site, but if someone is genuinely seeding all of your content, then I would expect this to be, at worst case, a neutral signal to Google. They will know how good the articles are, how often they are shared, who is posting them, etc.
Also, keep your anchor text neutral / clean. Don't over-optimise it as this will undoubtedly bring problems with it.
I don't really like plugging my own site, but have a read of this: http://bit.ly/1LyeiAh. You may get some additional info there.
-Andy