U.S. stock futures pointed to a lower open after weak overnight earnings from tech company Snap Inc SNAP.N sounded the alarm among investors ahead of earnings from Twitter Inc TWTR.N later on Friday. Despite Russian gas flowing back to Europe and some strong earnings in the region, political tension in Italy tempered sentiment as did the outlook for further central bank action on both sides of the Atlantic amid rising inflation. Mark Haefele, Chief Investment Officer at UBS Global Wealth Management, said he remained cautious about the outlook for stocks.